Sunlight through glass does not provide Vitamin D(nytimes.com)
nytimes.com
Sunlight through glass does not provide Vitamin D
https://www.nytimes.com/2019/02/08/well/live/does-sunlight-through-glass-provide-vitamin-d.html
345 comments
There is a lot of value in being able to see the outside. I can barely see outside from my position in the building and I feel it's really starting to eat my soul staring at walls the whole day.
Have you tried plants? I can't see windows from my desk, but I've got my cubicle filled with plants & it kind of makes up for it. One is a tropical shrub behind my monitors which would swallow my whole workstation if I didn't prune it back. Now if only people who seem to like the gloom would stop disconnecting bulbs in the fluorescent light fixtures..
There is evidence[1] that tropical plants and microorganisms in the soil will remove VOCs from sealed indoor environments, although the effect will likely be limited in an open plan office. At least they are nice to look at.
[1] https://en.wikipedia.org/wiki/NASA_Clean_Air_Study
[1] https://en.wikipedia.org/wiki/NASA_Clean_Air_Study
Critical Review: How Well Do House Plants Perform as Indoor Air Cleaners?
https://www.buildingecology.com/download/critical-review-how...
This might be of interest to you.
https://www.buildingecology.com/download/critical-review-how...
This might be of interest to you.
Oh... If only I could keep a plant alive in my office. I struggled with one for months, got it really healthy. Left instructions with co-worker and went to Europe for a month. While I was gone at least 5 people walked by that plant and said "oh, he's gone to Europe, I'd better water his plant for him". I get back and my plant is dead. My co-worker feels really, really bad about it and tells me he followed my interactions to the letter. It was over the course of 2 weeks that the other 4 people excitedly tell me that they watered my plant for me while I was gone, even though there was a little sign in it saying "please don't water me".
Facilities doesn't allow plants Everything needs to to dull, uniform and gray.
Leave.
(Edit: That sounds very depressing, and could be health affecting in the long term, so if you can, please do leave!).
(Edit: That sounds very depressing, and could be health affecting in the long term, so if you can, please do leave!).
Just bring one! They may not ask you to remove it.
Fluorescent light is typically low quality.
I would add early morning sunlight helps regulate circadian rhythm.
UVA is what causes skin cancers. Recommending or dismissing UVA exposure is irresponsible, especially in places with tons of UV radiation. Dermatologists go extra to teach people to choose sunscreen with good UVA protection, meanwhile Applied Science (one of my favourite youtubers) - “UVA penetrates regular window glass; hey its not to be worried about”...
Seems there's actually some debate on the net benefit/risk of this exposure [0]. Yes it raises risks for certain skin cancers but the survival rate of these is very high, meanwhile exposure decreases a collection of other risks whose death rates are much higher.
So I think the right course of action is a little more nuanced than simply saying, "UV increases skin cancer risk therefore ignore everything else as well as magnitudes of net risks/benefits". Should we not weigh all factors?
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
So I think the right course of action is a little more nuanced than simply saying, "UV increases skin cancer risk therefore ignore everything else as well as magnitudes of net risks/benefits". Should we not weigh all factors?
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
Actually, there was an article posted here (I think) not too long ago about a study that showed the positive benefits from sunlight were enough to outweigh the slightly increased chances of skin cancer.
I'll see if I can find the link.
I'll see if I can find the link.
Yeah I think it really varies by the region. Sure it's good to go outside in Sweden and England, but not in Aussie and NZ when you can get sunburn in about 15 minutes.
I've had couple of barbecue parties this summer in Auckland and NOBODY went outside until sun was way past 5PM. We preferred to sit in stuffy kitchen rather than enjoy beautiful beautiful outdoors. Even in middle of winter you can feel sun bite you as you stand in front of pedestrian crossing.
I've had couple of barbecue parties this summer in Auckland and NOBODY went outside until sun was way past 5PM. We preferred to sit in stuffy kitchen rather than enjoy beautiful beautiful outdoors. Even in middle of winter you can feel sun bite you as you stand in front of pedestrian crossing.
Trying to explain this to people visiting Australia is always amazing.
"It's so lovely and sunny here, why aren't you tan?"
"Because the sun is a terrifying ray of pain and death here."
"It's so lovely and sunny here, why aren't you tan?"
"Because the sun is a terrifying ray of pain and death here."
The sooner we completely phase out CFCs and other stratospheric ozone depleting gases, the sooner we can go back to the good old days where you could enjoy that sunshine.
The prediction is 2050-2070 we will be back to the 1980 level of ozone thickness.
The prediction is 2050-2070 we will be back to the 1980 level of ozone thickness.
Scientists have been trying to combat the perception that it is to blame for the high prevalence of skin cancer in Australia for a couple of decades now - it will never be a good idea to 'enjoy that sunshine' the way people used to.
(2001 paper - https://pdfs.semanticscholar.org/6944/503469e4f779e99884e144... " Sufferers of skin cancer today should more likely blame their affliction on skin type and sun exposure during their youth than any changes in ozone distributions over the last twenty years. Therefore it is safe to say that even without ozone depletion, Australia would still have a very high rate of skin cancer.")
(2001 paper - https://pdfs.semanticscholar.org/6944/503469e4f779e99884e144... " Sufferers of skin cancer today should more likely blame their affliction on skin type and sun exposure during their youth than any changes in ozone distributions over the last twenty years. Therefore it is safe to say that even without ozone depletion, Australia would still have a very high rate of skin cancer.")
Can't agree more. It was pretty crazy in the 70s/80s.
You had people literally baking themselves in the sun with tanning oils. Even after "Slip Slop Slap" was first promoted in the early 80s everyone was still trying to get a tan.
You had people literally baking themselves in the sun with tanning oils. Even after "Slip Slop Slap" was first promoted in the early 80s everyone was still trying to get a tan.
Wasn't the worst of the ozone thinning over the poles? Not sure the ozone layer actually affects sun exposure in Australia or NZ.
Over Antarctica, yes. But in some conditions (right winds? I forget) thinner patches of ozone do blow over the south coast of Australia, and does increase UV exposure.
...and this is why about a third of us NZers have vitamin D levels that are below the recommended level (5% + 27% ~ 1/3).
https://www.health.govt.nz/your-health/healthy-living/food-a...
https://www.health.govt.nz/your-health/healthy-living/food-a...
Yep, whether it does or doesn't give you skin cancer, sunburn is really unpleasant. That's enough to put most people off.
[deleted]
From wikipedia:
> Seasonal affective disorder is a mood disorder subset in which people who have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year, most commonly in the winter.
I usually get depressed in the summer though, even when I get enough unfiltered sunlight.
> Seasonal affective disorder is a mood disorder subset in which people who have normal mental health throughout most of the year exhibit depressive symptoms at the same time each year, most commonly in the winter.
I usually get depressed in the summer though, even when I get enough unfiltered sunlight.
There are all kind of things that happen seasonally that might dampen your mood (for instance people taking vacations, students being home from school, work being more/less busy, outdoor exercise options changing, etc). Your depression might not have anything to do with that and just be a random variation that happened to occur in the summer.
Most depression has nothing to do with SAD; it's merely a specific type. It's a type that has a fairly straightforward treatment, thankfully!
I often have a depressed mood in November and December when the sun is at its lowest, but my family also likes to make "the holidays" as miserable an experience as possible, so it's really no surprise and probably unrelated to light levels.
Most depression has nothing to do with SAD; it's merely a specific type. It's a type that has a fairly straightforward treatment, thankfully!
I often have a depressed mood in November and December when the sun is at its lowest, but my family also likes to make "the holidays" as miserable an experience as possible, so it's really no surprise and probably unrelated to light levels.
FWIW, I have the same symptoms in winter, but none of the reasons you list apply to me. I can easily see SAD being caused by lack of natural light, and I try to spend as much time as possible in sunlight (which is hard given a normal work schedule).
"most commonly", but there is some evidence that SAD is not triggered only by amount of light:
"This model also explains the otherwise confusing tendency of some SAD sufferers to get depressed in the summer. The problem isn’t amount of light, it’s circadian rhythm disruption – which summer can do just as well as winter can."
https://slatestarcodex.com/2018/07/10/melatonin-much-more-th...
"This model also explains the otherwise confusing tendency of some SAD sufferers to get depressed in the summer. The problem isn’t amount of light, it’s circadian rhythm disruption – which summer can do just as well as winter can."
https://slatestarcodex.com/2018/07/10/melatonin-much-more-th...
My question was: "Why does it block UVB?".
Found the answer on Quora: https://www.quora.com/Why-does-glass-block-UV
"With a band gap of 4eV, glass can't absorb any photons with less energy than UVB light; namely, it is transparent to UVA, visible light, infared, etc; but the higher energy photons can and are highly likely to be absorbed."
So it seems hard to create glass that doesn't block UVB.
Found the answer on Quora: https://www.quora.com/Why-does-glass-block-UV
"With a band gap of 4eV, glass can't absorb any photons with less energy than UVB light; namely, it is transparent to UVA, visible light, infared, etc; but the higher energy photons can and are highly likely to be absorbed."
So it seems hard to create glass that doesn't block UVB.
Feynman knew this and claims to be the only person to have watched the Trinity test with naked eyes, rather than through welding goggles:
> In Surely You’re Joking, Mr. Feynman, American physicist Richard Feynman speculates that he may have been the only person who watched the Trinity Test relatively directly, using a windshield to exclude ultraviolet light. Everyone else, he claims, was looking through something akin to welding goggles.
https://www.sindark.com/2011/02/22/feynman-and-the-trinity-t...
> In Surely You’re Joking, Mr. Feynman, American physicist Richard Feynman speculates that he may have been the only person who watched the Trinity Test relatively directly, using a windshield to exclude ultraviolet light. Everyone else, he claims, was looking through something akin to welding goggles.
https://www.sindark.com/2011/02/22/feynman-and-the-trinity-t...
I've never really understood this story. Feynman wasn't wrong, but UV-A and even sufficiently-bright visible light also cause eye damage.
Did he know the main visual hazard from the bomb was UV-B? Did he just get lucky?
Did he know the main visual hazard from the bomb was UV-B? Did he just get lucky?
We don't even know that he got lucky.
Lasers didn't exist yet to force us to study retinal exposure to bright non-UV light and the flash from the bomb didn't last that long, nor were the first few bombs that bright, so he may have been fine... but obviously if you stare at the sun through three inches of glass you're still going to burn your retinas.
He says "I figured the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet light. I got behind a truck windshield, because the ultraviolet can’t go through glass, so that would be safe, and so I could see the damn thing."
What we know from later laser research is that unless you have a comprehensive visual field test, it's often hard to identify that part of your retina has been scorched. Your brain just filters it out as a blind-spot and you don't realize what you're failing to see.
There's every chance that Feynman totally burned a section of his retina and never realized it, and there's every chance that he was fine because the exposure at his distance wasn't that bad, but at the end of the day he was more reckless than insightful in this situation.
Lasers didn't exist yet to force us to study retinal exposure to bright non-UV light and the flash from the bomb didn't last that long, nor were the first few bombs that bright, so he may have been fine... but obviously if you stare at the sun through three inches of glass you're still going to burn your retinas.
He says "I figured the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet light. I got behind a truck windshield, because the ultraviolet can’t go through glass, so that would be safe, and so I could see the damn thing."
What we know from later laser research is that unless you have a comprehensive visual field test, it's often hard to identify that part of your retina has been scorched. Your brain just filters it out as a blind-spot and you don't realize what you're failing to see.
There's every chance that Feynman totally burned a section of his retina and never realized it, and there's every chance that he was fine because the exposure at his distance wasn't that bad, but at the end of the day he was more reckless than insightful in this situation.
Maybe he should have closed one eye, but the first atomic bomb only explodes once. Your body won't last forever no matter how well you care for it (as Feynman well knew, having just watched his wife Arline die slowly of incurable tuberculosis); seeing the first atomic-bomb test with your own eyes seems eminently worth the risk of blindness, or even sacrificing an eye.
I really can't agree. I would not exchange my eyesight for the whole world, literally. Therefore the qudos of having looked at a novel explosion in no way compensates for any risk to my eyes.
>I would not exchange my eyesight for the whole world, literally.
FYI vacuum exposure can cause blindness, visual impairment, and death.
FYI vacuum exposure can cause blindness, visual impairment, and death.
kragen(3)
> bright light can never hurt your eyes
Before y'all criticize that statement, keep in mind it's coming from one of the best scientists of the 20th century.
He was talking before lasers. For a purely thermal source to hurt the eyes, it would have to be:
1. insanely hot
2. quite close to the observer
First condition is met by the nuke, but the second one, obviously, is not, unless you're a victim of the explosion.
Before y'all criticize that statement, keep in mind it's coming from one of the best scientists of the 20th century.
He was talking before lasers. For a purely thermal source to hurt the eyes, it would have to be:
1. insanely hot
2. quite close to the observer
First condition is met by the nuke, but the second one, obviously, is not, unless you're a victim of the explosion.
Scientists, even the best ones, do dumb things all the time.
Source: Am experimental physicist; do dumb things. Sometimes my colleagues do too, even the best ones.
Source: Am experimental physicist; do dumb things. Sometimes my colleagues do too, even the best ones.
Los Alamos was replete with brilliant people doing dangerously stupid things.
https://en.wikipedia.org/wiki/Demon_core
https://en.wikipedia.org/wiki/Demon_core
I know. It was not meant as an absolute statement.
As much as a window blocks UV, I wouldn't trust a laser if a high-powered UV laser was aimed through it at my eye.
I have a scar on my retina near the fovea, and I can only see it if I deliberately focus on it.
Are we sure he wasn’t wearing sunglasses too?
Yep, he basically says that he knew the only thing that would damage his eyes would be UV-B, so he just went for it. Long time since I read the book but that's what I remember.
> Feynman knew this and claims to be
I don't get this type of thinking. Unless he thought it would be worse to wear the googles what is to be gained by doing something like wearing goggles (in that situation) just in case you were wrong? Why not reduce the chance of harm as much as you can?
I don't get this type of thinking. Unless he thought it would be worse to wear the googles what is to be gained by doing something like wearing goggles (in that situation) just in case you were wrong? Why not reduce the chance of harm as much as you can?
Because he was a curious man and wanted to see every detail?
I think this also has to be considered in the context of an ongoing cataclysmic war encompassing the world where whole cities were being destroyed and of course they were developing a weapon to destroy them faster. Today, WWII is that long ago thing that lasted for a few years and then it was over. Soon the veterans and the Holocaust survivors will all be dead. To anyone then, a lot of things probably didn't seem as important. A lot of people reacted to the atomic bomb once it was public as the impending end of the world, too. So the scientists who knew about it first probably had their attitudes affected.
There's a fine line between genius and madness.
You probably can't see shit with those goggles.
The window didn't block a lot of other high power radiation, and he died from cancer 35 years later, though the connection is not scientifically certain.
He was also smoker. He also lived in Los Alamos during its development where the cancer rates where significantly higher
43 years later (Trinity test was in 1945, he died in 1988).
[deleted]
Sorry, my morning coffee must have been weak.
There's a great Applied Science video on the various light absorption properties for various materials here: https://www.youtube.com/watch?v=vwsHRrDYu5o
So in case anyone just panicked thinking “Wait, so do my car and office windows block cancer producing UV or not??”, this is what I found on cancercouncil.com.au (first google result):
- UVA penetrates deeply into the skin (the dermis) causing genetic damage to cells, photo-ageing (wrinkling, blotchiness etc) and immune-suppression.
- UVB penetrates into the epidermis (top layer of the skin) causing damage to the cells. UVB is responsible for sunburn – a significant risk factor for skin cancer, especially melanoma.
Which contrary to what I knew, links melanoma to sunburn, not DNA damage.
- UVA penetrates deeply into the skin (the dermis) causing genetic damage to cells, photo-ageing (wrinkling, blotchiness etc) and immune-suppression.
- UVB penetrates into the epidermis (top layer of the skin) causing damage to the cells. UVB is responsible for sunburn – a significant risk factor for skin cancer, especially melanoma.
Which contrary to what I knew, links melanoma to sunburn, not DNA damage.
A good example of what UVA does would be the famous trucker with sun damage to one side of his face-
https://www.huffingtonpost.ca/2012/06/06/bill-mcelligott-sun...
https://www.huffingtonpost.ca/2012/06/06/bill-mcelligott-sun...
Here's an archive for those getting Oath'd
http://archive.is/aVhiM
http://archive.is/aVhiM
Or the source: https://www.nejm.org/doi/full/10.1056/NEJMicm1104059
Well this has made me reconsider my lack of use of sun screen. Thanks for sharing.
I'm stuck between a rock and a hard place because this article makes a lot of sense.
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
I think I'm just going to use daily sunscreen on my face only.
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
I think I'm just going to use daily sunscreen on my face only.
Melanoma is definitely due to DNA damage; somatic mutation is the principal cause of all cancer. In this case the cause is either direct damage or damage by free radical byproducts created by UV. UV causes a kind of mutation in DNA called a pyrimidine dimer, where two adjacent bases mutate at once. By far the most common mutation in melanoma (reponsible for 50% of cases) is a CC to TT mutation at position 600 of the gene BRAF.
The UV damages the DNA. That step is usually required to produce melanoma cancer. The sunburn causes the deeper cells with damaged DNA to multiply in order to replace the damaged cells.
A single quiescent skin cell with precancerous DNA can be cleaned up by the immune system. A precancerous cell that has multiplied itself to cover a patch of sunburn, activating some of the genes for rapid growth, is much harder to clean up.
A single quiescent skin cell with precancerous DNA can be cleaned up by the immune system. A precancerous cell that has multiplied itself to cover a patch of sunburn, activating some of the genes for rapid growth, is much harder to clean up.
Well, when you get sunburn i.e. high UVB exposure, you get high UVA exposure, too. My understanding is, that UVA radiation causes cancer.
But I would like to see some clarification on this topic, too.
But I would like to see some clarification on this topic, too.
UVB causes melanoma, that is also a form of cancer. So typical glass would prevent sunburn and melanomas from forming but not the deep genetic and tissue damage that UVA causes. It is not a bad idea to apply SPF moisturizer before going out if you plan to spend anytime with the sun shining on you.
UVA causes DNA damage (and potentially cancer) indirectly via oxidation.
From what I read UVB melanoma is an "easy" type of cancer.
From what I read UVB melanoma is an "easy" type of cancer.
> So in case anyone just panicked thinking “Wait, so do my car and office windows block cancer producing UV or not??”
I just figured automotive glass doesn't block UV (or at least all of it) since window tinting places always advertise UV blocking as a feature of their films. Cynically I know it could be just empty marketing, but it didn't seem like it.
I just figured automotive glass doesn't block UV (or at least all of it) since window tinting places always advertise UV blocking as a feature of their films. Cynically I know it could be just empty marketing, but it didn't seem like it.
Of course, ordinary light, while still less energetic, penetrates still more deeply into skin, and it, too causes DNA damage. In situ DNA is damaged by light absorbed by less transparent molecules it is near.
Quartz glass is transparent to the UV range, so it's not so much that we don't have the technology, it's just way more expensive than regular glass.
Sapphire's also transparent down to far ultraviolet (150nm). Not sure about ALON.
Replying to self (because the edit window has gone): ALON apparently goes down to 200nm, so it's transparent to UVB (280-315)
Sapphire is an incredibly trivial compound, aluminum oxide.
The problem is, its melting point is huge. To make artificial sapphire you have to melt the stuff at very high temperature and let it drop and collect onto a ceramic base or something. And then you cut, grind and polish it into shape, which is not easy either because it's an extremely hard material.
The challenges to making a large flat plate of AlOx would be huge.
The problem is, its melting point is huge. To make artificial sapphire you have to melt the stuff at very high temperature and let it drop and collect onto a ceramic base or something. And then you cut, grind and polish it into shape, which is not easy either because it's an extremely hard material.
The challenges to making a large flat plate of AlOx would be huge.
Nikon released a lens in 1984 that offered transmission and correction from UV to IR -- from ultraviolet, through visible light, to infrared (near IR, not heat).
http://www.company7.com/nikon/lens/0105f4.5uv.html
This product was originally announced in 1984 as the Nikon 105mm f/4.5 UV-Micro-Nikkor, and from September 1985 it was marketed as the Nikon UV-Nikkor, then the lens sold then for $2,200.00 USD, then about half the cost of a full sized car.
http://www.company7.com/nikon/lens/0105f4.5uv.html
This product was originally announced in 1984 as the Nikon 105mm f/4.5 UV-Micro-Nikkor, and from September 1985 it was marketed as the Nikon UV-Nikkor, then the lens sold then for $2,200.00 USD, then about half the cost of a full sized car.
Mildly amusing related aside from this. Because of this, glass is completely opaque in the UV spectrum. Looking at the world in UV [1] is quite interesting! Such a reminder that how and what we experience of the world is so largely a product of our physiological composition. What is perfectly transparent to us would be a great hiding place from the perspective of something that only saw in UV.
[1] - https://www.youtube.com/watch?v=V9K6gjR07Po
[1] - https://www.youtube.com/watch?v=V9K6gjR07Po
Other comments say glass does not block UVA
[deleted]
My grandfather, who was an ophthalmologist with a passion for inventing, has shown me schematics for this kind of glass. His idea was that you could put it in places that are sunny but not warm (like a mountain hotel) to allow for indoor sunbathing.
We always make fun of him for this idea as it's one of his strangest. I don't think he ever finished filing the patent.
We always make fun of him for this idea as it's one of his strangest. I don't think he ever finished filing the patent.
> So it seems hard to create glass that doesn't block UVB.
Physics aside, why would you want to do that in the first place? UVB is the chief cause of skin reddening and sunburn and plays a key role in the development of skin cancer and a contributory role in tanning and photoaging. [1]
Just for that little benefit of triggering Vitamin D synthesis is not worth the increased risk of skin cancer IMO. And the author lays out the alternative there too: "Those concerned about low vitamin D levels can get more of the vitamin through foods. "
[1]: https://www.skincancer.org/prevention/uva-and-uvb
Physics aside, why would you want to do that in the first place? UVB is the chief cause of skin reddening and sunburn and plays a key role in the development of skin cancer and a contributory role in tanning and photoaging. [1]
Just for that little benefit of triggering Vitamin D synthesis is not worth the increased risk of skin cancer IMO. And the author lays out the alternative there too: "Those concerned about low vitamin D levels can get more of the vitamin through foods. "
[1]: https://www.skincancer.org/prevention/uva-and-uvb
There is an alternative view that regular sun exposure is beneficial, and that many of the health benefits linked to vitamin D are actually just using vitamin D as a proxy for sun exposure. If this is the case, it's plausible that allowing for more UVB exposure indoors would be a net benefit.
Previous HN discussion: https://news.ycombinator.com/item?id=18890475
Previous HN discussion: https://news.ycombinator.com/item?id=18890475
I don't doubt that sun exposure is a contributing factor to skin cancer, but it just does not make sense that skin cancer rates have shot up over the past 100 years, while at the same time people spend less and less time outside.
IMO, there's probably some other causal factor(s), and reducing sunlight exposure is not the solution.
Sunlight exposure is important for health, not just for Vitamin D (which others have pointed out, may just be a proxy for some other factor of sun exposure). It's important for regulating circadian rhythm, as well as preventing myopia in childhood.
IMO, there's probably some other causal factor(s), and reducing sunlight exposure is not the solution.
Sunlight exposure is important for health, not just for Vitamin D (which others have pointed out, may just be a proxy for some other factor of sun exposure). It's important for regulating circadian rhythm, as well as preventing myopia in childhood.
If you take a dive on PubMed, you'll see that indeed, sunlight exposure appears to be inversely correlated with all-cause mortality.
Why? It is not known, but even when controlling for physical exercise, Vitamin D status, and other factors, the correlation still holds. Some authors suggest other chemicals produced by sunlight, not only Vitamin F, might be involved.
Why? It is not known, but even when controlling for physical exercise, Vitamin D status, and other factors, the correlation still holds. Some authors suggest other chemicals produced by sunlight, not only Vitamin F, might be involved.
(correction to above, I meant Vitamin D, not F, of course).
> Physics aside, why would you want to do that in the first place?
I worked on a product that had a UV sensor. It needed to be protected.
Sourcing glass that didn't block UVB, that could be used in a mass market product, at cost, integrated into a manufacturing line, was a bit of a challenge. The mechanical engineering team eventually got a hold of some. For awhile, there were weekly status updates of "got another manufacturing sample, spec sheet wasn't quite honest, it blocks some UVB."
I worked on a product that had a UV sensor. It needed to be protected.
Sourcing glass that didn't block UVB, that could be used in a mass market product, at cost, integrated into a manufacturing line, was a bit of a challenge. The mechanical engineering team eventually got a hold of some. For awhile, there were weekly status updates of "got another manufacturing sample, spec sheet wasn't quite honest, it blocks some UVB."
Depends for some skin conditions its better to have timed exposure via UVB therapy - I have had this in the past.
The answer to all such questions is - something related to energy levels of electrons in that material. If there's a resonance somewhere, photons at that energy get absorbed.
Soda-lime glass transmits pretty much all UV ranges and is readily manufactured (it is used often in germicidal lamps.)
You can coat it - sunglasses are, for example. The coating can be invisible to the naked eye too, I think.
This is one of those situations where I think government intervention is needed. I bet the long-term benefits of coating glass like this are very real - both for society and individually (especially in professions that involve a lot of driving time). However, the short-term economic incentives work against it - there is probably a strong first-move disadvantage. Also, what is the economic benefit to a landlord to have UV-proofed glass for their tenants?
But if government were to implement a policy of requiring glass in cars and buildings to be coated like that? That levels the playing field. I doubt it is going to happen any time soon though.
But of we were ever going to to do that, I know for a fact that are also coatings with reflective layers (invisible to us) that tell birds that the glass is there, which would also save a lot of wildlife.
This is one of those situations where I think government intervention is needed. I bet the long-term benefits of coating glass like this are very real - both for society and individually (especially in professions that involve a lot of driving time). However, the short-term economic incentives work against it - there is probably a strong first-move disadvantage. Also, what is the economic benefit to a landlord to have UV-proofed glass for their tenants?
But if government were to implement a policy of requiring glass in cars and buildings to be coated like that? That levels the playing field. I doubt it is going to happen any time soon though.
But of we were ever going to to do that, I know for a fact that are also coatings with reflective layers (invisible to us) that tell birds that the glass is there, which would also save a lot of wildlife.
I think you're inverting what parent is saying. Glass by nature seems to block UVB.
Ah, right. I somehow thought GP suggested near the end that it seems to be hard to fabricate glass that blocks UVA, and answered the question of how to deal with that.
How does coating it prevent the glass itself absorbing UVB?
As Waterluvian pointed out, I misread GP and explained how we could make glass block UVA as well.
Ah, yes the classic "government intervention to attack a misunderstood problem with a solution that won't work".
Ah yes, the classic "I just assert that governments can only intervene with wrong solutions, without in any way engaging with the topic at hand and actually arguing why it is a wrong solution."
Well it’s a wrong solution since glass already filters it. Seems a bit premature to salivate over regulation for something that isn’t a problem.
Did you read the other comments? I misread GP and the coating I talked about is for UVA radiation.
> Those concerned about low vitamin D levels can get more of the vitamin through foods.
As someone who had a number of health issues whose underlying cause was a vitamin D deficiency I do not agree.
There is no substitute for light. Supplementing with D3 had very limited effect. Using a vitamin d lamp however was a world changer within days.
As someone who had a number of health issues whose underlying cause was a vitamin D deficiency I do not agree.
There is no substitute for light. Supplementing with D3 had very limited effect. Using a vitamin d lamp however was a world changer within days.
Was your supplement dosage enough though? In the order of 10000 IU per day?
The problem with vitamin D was that up until about a year ago, official recommendations in many countries were mistakenly low (500-1000 IUs), which as it turned out, was not enough for many people. It was even hard to find proper pills that has high enough dosages, because when you got to your local farmacist which was going by the official recommendations, all they had were 200-500 IU pills, because they were not expecting that anyone would need more. So as an average citizen who does not do their research properly, if they just went into a farmacist and took the first Vitamin D supplement they saw, the chances were that they were getting one which had basically no effect.
When the dosage is right, many people experience positive effects and dormant Vitamin D levels really do go up. The sun is not required.
The problem with vitamin D was that up until about a year ago, official recommendations in many countries were mistakenly low (500-1000 IUs), which as it turned out, was not enough for many people. It was even hard to find proper pills that has high enough dosages, because when you got to your local farmacist which was going by the official recommendations, all they had were 200-500 IU pills, because they were not expecting that anyone would need more. So as an average citizen who does not do their research properly, if they just went into a farmacist and took the first Vitamin D supplement they saw, the chances were that they were getting one which had basically no effect.
When the dosage is right, many people experience positive effects and dormant Vitamin D levels really do go up. The sun is not required.
The problem with Vit D3 supplement is that you don’t absorb most of it. It is well known, than the bioavailability of the supplements is not the same and that even the molecule itself is not the same as the one your organism produces.
Also, the science is starting to question the supplementation. It’s too early to tell, but one hypothesis is that it is a biomarker at the end of a pathway and not at the beginning of it, i.e. as a consequence of a proper diet and sunlight, and not a cause of a healthy system.
Also, the science is starting to question the supplementation. It’s too early to tell, but one hypothesis is that it is a biomarker at the end of a pathway and not at the beginning of it, i.e. as a consequence of a proper diet and sunlight, and not a cause of a healthy system.
So the vitamin D might be there due to a healthy system instead of the system being healthy due to vitamin D.
An analogy would be the analysis of car exhaust, finding certain levels of CO2, and trying to fix cars with "bad exhaust" by throwing more CO2 into the intake (except maybe this would even have a negative effect by hindering combustion).
An analogy would be the analysis of car exhaust, finding certain levels of CO2, and trying to fix cars with "bad exhaust" by throwing more CO2 into the intake (except maybe this would even have a negative effect by hindering combustion).
> An analogy would be the analysis of car exhaust, finding certain levels of CO2, and trying to fix cars with "bad exhaust" by throwing more CO2 into the intake (except maybe this would even have a negative effect by hindering combustion).
This is an hilarious (and fitting) analogy for nutrition sciences.
This is an hilarious (and fitting) analogy for nutrition sciences.
There was a classic TV ad by an oil company that said that CO2 is great because it is plant food. It's still an argument used by folks who oppose CO2 controls.
> It is well known, than the bioavailability of the supplements is not the same and that even the molecule itself is not the same as the one your organism produces.
Reputed and trustworthy citations from scientific sources required, please.
Reputed and trustworthy citations from scientific sources required, please.
Every cholecalciferol molecule is the same. This is chemistry. Chemicals that are not the same cannot have the same chemical name. Every animal (without a genetic defect specific to the precursor chemicals) produces the same 7-dehydrocholesterol molecules, and every 7-dehydrocholesterol will, under UVB light, convert to cholecalciferol.
Industrial production of vitamin D3 irradiates the 7-dehydrocholesterol extracted from sheep's lanolin with UVB light.
There is some question as to whether ergocalciferol--a chemical mainly found in fungi that produce ergosterol and have been exposed to UVB light--is biologically equivalent to cholecalciferol in humans. It can alleviate vitamin D deficiency symptoms, but it is not known with certainty whether it can produce a sufficiency. As far as I am aware, the known cases of hypervitaminosis D have resulted from ergocalciferol supplementation, rather than from cholecalciferol.
If you are supplementing with vitamin D3, the chemical you are consuming is identical to that produced in your skin under UVB irradiation. There is no evidence whatsoever that it is destroyed in or poorly absorbed by the human digestive system. If you swallow 15000 IU of vitamin D3, that is the equivalent of standing shirtless in temperate midday sun for 15 minutes, after which time you will achieve no further benefit until some time has been spent absorbing the cholecalciferol and replenishing the 7-dehydrocholesterol in your skin.
It is poorly known, that if you have to preface a statement with "it is well known", what follows is less likely to be "known" than "unattributably rumored".
Industrial production of vitamin D3 irradiates the 7-dehydrocholesterol extracted from sheep's lanolin with UVB light.
There is some question as to whether ergocalciferol--a chemical mainly found in fungi that produce ergosterol and have been exposed to UVB light--is biologically equivalent to cholecalciferol in humans. It can alleviate vitamin D deficiency symptoms, but it is not known with certainty whether it can produce a sufficiency. As far as I am aware, the known cases of hypervitaminosis D have resulted from ergocalciferol supplementation, rather than from cholecalciferol.
If you are supplementing with vitamin D3, the chemical you are consuming is identical to that produced in your skin under UVB irradiation. There is no evidence whatsoever that it is destroyed in or poorly absorbed by the human digestive system. If you swallow 15000 IU of vitamin D3, that is the equivalent of standing shirtless in temperate midday sun for 15 minutes, after which time you will achieve no further benefit until some time has been spent absorbing the cholecalciferol and replenishing the 7-dehydrocholesterol in your skin.
It is poorly known, that if you have to preface a statement with "it is well known", what follows is less likely to be "known" than "unattributably rumored".
No it’s not required. This is a discussion board not a thesis paper review board. Do your own googling. If he or she is wrong then call bullshit.
It is required. Just claiming something is well-known to counter someone’s suggestion without providing any evidence isn’t very productive.
No other suggestion was offered in the post I am referring to, just a "sources pl0x" ask. Here is the simplest counter example I can think of.
"Gravity is real."
"Reputed and trustworthy citations from scientific sources required, please."
You can get less and less ridiculous from here ad nauseam, but the point is made.
"Gravity is real."
"Reputed and trustworthy citations from scientific sources required, please."
You can get less and less ridiculous from here ad nauseam, but the point is made.
"It is well known" is a weasel word, and hence requires more substantiation when asked. If one has to rely on Googling on these matters, one can find so many contradictory views. So I wanted to know what reputed sources the GP was relying on to use "It is well known" for that claim.
how about just search hacker news?
https://www.npr.org/sections/health-shots/2018/11/10/6665455...
https://www.theguardian.com/science/2018/mar/09/is-vitamin-d...
And those studies saying otherwise have been backed by a lot of questionable money: https://www.nytimes.com/2018/08/18/business/vitamin-d-michae...
Oh by the way sunscreen is terrible, it doesn't have a proven link to reducing cancer and it destroys reefs so do yourself a favor and get more sun without all the slimy goop so you can feel better AND save the planet!
https://www.theguardian.com/science/2018/mar/09/is-vitamin-d...
And those studies saying otherwise have been backed by a lot of questionable money: https://www.nytimes.com/2018/08/18/business/vitamin-d-michae...
Oh by the way sunscreen is terrible, it doesn't have a proven link to reducing cancer and it destroys reefs so do yourself a favor and get more sun without all the slimy goop so you can feel better AND save the planet!
Pairing K2, or consuming vegetables high in vitamin K, helps with this. Personally I both consume a supplement and use a SAD light.
Do you have a source for the 10000 IU per day guideline? If that's D3, that's 25 times to "recommended" amount, well above what is considered safe for long-term use. Now, I realize that our understanding of these things are in a state of (often violent) flux, but I would like to know who's recommended such a high amount. The problem with Vitamin D is that it is fat-soluble, not water-soluble, so your body doesn't expel the excess very quickly and it builds up. Too much can be harmful, particularly to your bones and kidneys[1].
[1] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...
[1] https://www.mayoclinic.org/healthy-lifestyle/nutrition-and-h...
> well above what is considered safe for long-term use.
The Mayo clinic article says:
> Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity.
So 10,000, while it's well above the "recommended" dosage, is nowhere near the toxic level. Although when I was looking around the toxic level was 20,000, still, I've seen no guidance regarding Vitamin D that suggests 10,000 IUs/day can be toxic. (Especially if your BMI is over 25, and you're not getting much sunlight.)
The Mayo clinic article says:
> Taking 60,000 international units (IU) a day of vitamin D for several months has been shown to cause toxicity.
So 10,000, while it's well above the "recommended" dosage, is nowhere near the toxic level. Although when I was looking around the toxic level was 20,000, still, I've seen no guidance regarding Vitamin D that suggests 10,000 IUs/day can be toxic. (Especially if your BMI is over 25, and you're not getting much sunlight.)
Mayo clinic article concerns excessive supplementation, isolated on vitamin D, specifically.
A hypothesis exists that increasing vitamin K consumption in proportion to the vitamin D, and restricting calcium intake, would eliminate the main symptoms of excessive vitamin D supplementation. Nonhuman animal experimentation confirms, but it has not been tested in humans (likely due to the obvious ethical concerns).
Vitamin D, vitamin K, and calcium are all related.
I have seen guidance specifically for vitamin D2 (ergocalciferol), indicating that adverse symptoms may be observed at lower levels of supplementation than for vitamin D3 (cholecalciferol), but it was quite some time ago, and I don't know if the claim was confirmed or refuted scientifically.
A hypothesis exists that increasing vitamin K consumption in proportion to the vitamin D, and restricting calcium intake, would eliminate the main symptoms of excessive vitamin D supplementation. Nonhuman animal experimentation confirms, but it has not been tested in humans (likely due to the obvious ethical concerns).
Vitamin D, vitamin K, and calcium are all related.
I have seen guidance specifically for vitamin D2 (ergocalciferol), indicating that adverse symptoms may be observed at lower levels of supplementation than for vitamin D3 (cholecalciferol), but it was quite some time ago, and I don't know if the claim was confirmed or refuted scientifically.
Remember that 60,000 was chosen so that toxicity could be very reliably demonstrated. It does not mean that lower doses are not also toxic.
I'm always worried about how easy it would be for manufacturers to accidentally put more in a pill than the label says.
10,000 IU is only 1.25 mg, and vitamins aren't well regulated. It's not like you'd notice if your supplement contained 100,000 IU.
10,000 IU is only 1.25 mg, and vitamins aren't well regulated. It's not like you'd notice if your supplement contained 100,000 IU.
That happens all the time. Please check https://labdoor.com/ before buying any unregulated drug.
Oh dammit! I wish I had seen this before I went to the drug store...
USP and other certifications are supposed to address this, but the onus is on the consumer to seek out the certification label.
http://www.usp.org/verification-services/verified-mark
Others include NSF, UL, and consumerlab
https://www.consumerreports.org/vitamins-supplements/what-us...
There's still the chance that a manufacturing mistake could result in bad dosage but that applies to all products including medicine.
http://www.usp.org/verification-services/verified-mark
Others include NSF, UL, and consumerlab
https://www.consumerreports.org/vitamins-supplements/what-us...
There's still the chance that a manufacturing mistake could result in bad dosage but that applies to all products including medicine.
Vitamin D is particularly worrisome to me because a few milligrams is the difference between therapeutic and toxic.
... and in fact it has happened. With drops for infants that had a 75 times too high concentration:
http://cphpost.dk/news/danish-health-authority-warns-of-toxi...
http://cphpost.dk/news/danish-health-authority-warns-of-toxi...
I know you have faith that taking large doses of vitamin d isn't dangerous, but there is very little evidence supporting its value. We all have to make serious decisions every day without scientific support, so I don't begrudge you the right to do what you believe is best for you. But don't you think it's a little irresponsible to try to convince people that this belief of yours is actually effective? AFICT, there's as good a change that your advice will take ten years off of a life as it has of improving life. And you want to push this on others?
Mark Hyman made post on it(he is Hillary Clinton’s doctor): https://drhyman.com/blog/2010/08/24/vitamin-d-why-you-are-pr...
That's a good read. He says you can go high (10000 IU/day) for 6-10 months, under doctor's supervision, then cut back down 2000-4000/day. This also makes sense from the perspective that it's fat-soluble, so you should be able to "fill up the tank" as he puts it.
Thankfully it was posted to HN so I could find it. Google search has a truly become useless for this stuff. It's early in the morning, but I think I'm reading the abstract right. [1]
1. https://www.ncbi.nlm.nih.gov/m/pubmed/28768407/
1. https://www.ncbi.nlm.nih.gov/m/pubmed/28768407/
Try google scholar next time instead of regular google search.
To add some anecdotal info, those numbers are much more closer to my own personal experience. I've been experimenting with various dosages, with regular blood tests by a doctor, for a few years now. Currently I've setteled at 4000 IU/day to stay at 75 nmol/L, which is the lower end of what is considered normal.
Excellent! Thank you!
I would be very careful with liposoluble vitamines, they can aggregate in your fat tissue and cause toxic effects
It was 6000+
Was it gelcaps or dry tablets? Vitamin D is fat-soluble so much better absorbed in gelcap format (and taken with a meal).
Personally, I've been taking 5000 IUs/day and recently started stepping that closer to 10,000 IUs. I use the liquid drops which are in oil, and I always try to take them with some sort of meal. The liquid is a lot cheaper and seems like the ideal way to absorb it to me.
This is in cloudy wintertime Seattle. In sunny times it may be completely unnecessary.
This is in cloudy wintertime Seattle. In sunny times it may be completely unnecessary.
Just another anecdote, a friend of mine with Lyme Disease has serious problems absorbing vitamin D (and other nutrients) via food, his doctor has him on 10K per day.
If I recall correctly, such a treatment is not yet evidence based, though clinical trials are ongoing.
That is interesting. I had read that 500 was ineffective but did not know that 10000 was effective. If you've done the research what is the most reliable source you found
?
taking vitamin D at such a high dose can give you health problems such as kidney stones. When I took 5000 IUs for a period of time I started getting painful kidneys just from the urinary effects.
Now I try to get my vitamin D through more normal sources by eating lots of UV-exposed mushrooms, salmon, and sardines. Plus side is these foods are all quite healthy even without the vitamin D
Now I try to get my vitamin D through more normal sources by eating lots of UV-exposed mushrooms, salmon, and sardines. Plus side is these foods are all quite healthy even without the vitamin D
I didn't have any problems getting 20k IU in the UK had to get it prescribed
There is research implying that levels of vitamin D are only an indicator of good health, and does not cause it (i.e. correlation instead of causation): https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
OP would still likely be fixing their problem though, right? That article says it is the sun exposure itself that has a positive effect, and vitamin D is the byproduct.
To be clear, that's a really useful article, just want to clarify that your intent is indeed to explain why vitamin D wouldn't work but a UVB lamp would.
To be clear, that's a really useful article, just want to clarify that your intent is indeed to explain why vitamin D wouldn't work but a UVB lamp would.
Another possibility: higher vitamin D levels are associated with health because people who are outside more might be getting more exercise, and it's really the exercise that is doing it.
It's hard to disentangle all these things.
It's hard to disentangle all these things.
Exactly.
A related article that was on here recently-
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
Vitamin D is something we can measure and often serves as an indicator, but large scale tests have shown limited effectiveness of supplements at resolving the issues a Vitamin D deficiency causes. e.g. We increase blood Vitamin D, but there are unknown correlative mechanisms that we aren't substituting.
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
Vitamin D is something we can measure and often serves as an indicator, but large scale tests have shown limited effectiveness of supplements at resolving the issues a Vitamin D deficiency causes. e.g. We increase blood Vitamin D, but there are unknown correlative mechanisms that we aren't substituting.
Good, straightforward advice from the NHS here. https://www.nhs.uk/conditions/vitamins-and-minerals/vitamin-... - just about the only vitamin that they recommend supplementing orally for the general population, at least during the winter months.
The evidence on this seems to be changing frequently, not unlike the evidence on whether taking vitamin supplements is a good idea (https://www.health.harvard.edu/staying-healthy/should-you-ge...). Generally speaking, the latest science on nutrition seems to be more subject to later revision, or even reversal, than the latest science on, say, physics or geology.
So, while we wait (perhaps decades) for nutrition to become a more reliable science, I like to consider it from an evolutionary angle. That which is very dissimilar to what my ancestors experienced, like plentiful sugar or a sedentary lifestyle, is more likely to be bad for my health.
Exposure to the sun for hours a day, including the UV part, was part of our ancestors' lifestyle from the beginnings of our species, until a few decades ago. Now it is possible that this is the exception, and we should keep ourselves shielded from UV at all times even though it was what we evolved for. But...
- we don't now much about our skin microbiome, but we know we have one and it matters, and it seems unlikely that removing all UV would not impact that - we know there's an impact on vitamin D levels, but the details of that are still unknown - we know that eczema, psoriasis, and other skin conditions have been rising in recent decades, since the "always wear sunscreen" advice became common
Now, many that's all a coincidence, and UV is bad for us, and lack of UV is good for us, regardless of the fact that it's the environment we evolved for. But I'm skeptical.
So, while we wait (perhaps decades) for nutrition to become a more reliable science, I like to consider it from an evolutionary angle. That which is very dissimilar to what my ancestors experienced, like plentiful sugar or a sedentary lifestyle, is more likely to be bad for my health.
Exposure to the sun for hours a day, including the UV part, was part of our ancestors' lifestyle from the beginnings of our species, until a few decades ago. Now it is possible that this is the exception, and we should keep ourselves shielded from UV at all times even though it was what we evolved for. But...
- we don't now much about our skin microbiome, but we know we have one and it matters, and it seems unlikely that removing all UV would not impact that - we know there's an impact on vitamin D levels, but the details of that are still unknown - we know that eczema, psoriasis, and other skin conditions have been rising in recent decades, since the "always wear sunscreen" advice became common
Now, many that's all a coincidence, and UV is bad for us, and lack of UV is good for us, regardless of the fact that it's the environment we evolved for. But I'm skeptical.
There's another important factor to consider, and that's how we expose ourselves to UV. Our ancestors used to be outside most of the day, allowing skin pigmentation to adapt to the regional and seasonal UV levels. Until agriculture came along fairly recently we also lived mostly in the shade of the forest and not in direct sunlight.
Compare that to today, where UV exposure mostly means exposing the skin to massive bursts of UV for short times, at best in an effort to build skin pigmentation that isn't sufficient. That's completely different and much more damaging, leading to the general feeling that any UV is bad.
Compare that to today, where UV exposure mostly means exposing the skin to massive bursts of UV for short times, at best in an effort to build skin pigmentation that isn't sufficient. That's completely different and much more damaging, leading to the general feeling that any UV is bad.
We are also a lot cleaner. We remove dirt and dead skin, whereas our ancestors left it there and it may have acted as a protective shield from UV.
I think our ancestors lived in the full sun of the African savannah a lot more than the forest, and even in northern Europe, hunter gatherers were killing meat-on-the-hoof (mammoth, wild horse, etc.) so they were running about in the open a lot.
However, the change in exposure is surely true. I'm just not at all convinced that complete shielding from UV is a better choice than occasional UV.
Until recently, children would run around outside a lot during the summer, even in urban environments, and especially in suburban or rural ones.
However, the change in exposure is surely true. I'm just not at all convinced that complete shielding from UV is a better choice than occasional UV.
Until recently, children would run around outside a lot during the summer, even in urban environments, and especially in suburban or rural ones.
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Be careful of the natural fallacy. Life expectancy was much lower a long time ago, and causes of death from poor health were not recorded very accurately.
Choosing the natural over the artificial is a reasonable default where the science is uncertain. But just remember that science has eliminated an awful lot of problems.
Also remember that natural experiences aren't always a la carte. Picking natural foods from disperate regions might be very unnatural, as is getting natural UV light after taking a shower.
Choosing the natural over the artificial is a reasonable default where the science is uncertain. But just remember that science has eliminated an awful lot of problems.
Also remember that natural experiences aren't always a la carte. Picking natural foods from disperate regions might be very unnatural, as is getting natural UV light after taking a shower.
Certainly, many natural things are not good. However, the idea that a complete absence of natural light (which includes UV) is good, is suspect. It reminds one of the idea, in the early 20th century, that getting rid of all bacteria was good. It turns out that there are way more kinds of bacteria than we know, and an excess of antibiotics and disinfectants is almost certainly a big part of why we have ever-escalating rates of severe allergies and auto-immune disorders.
Not that we would wish to have a complete absence of antibiotics. But, the attitude of "you have a virus, so take this antibiotic just in case there's also a bacteria", sounds a lot like "block all UV light from hitting your skin, at all times". I am skeptical.
Not that we would wish to have a complete absence of antibiotics. But, the attitude of "you have a virus, so take this antibiotic just in case there's also a bacteria", sounds a lot like "block all UV light from hitting your skin, at all times". I am skeptical.
I mostly agree. I'm just saying that you might want to stop using soap as well ;-)
Using soap has a big effect on how the UV light hits your skin, the damage it might cause, and the benefits that it might have. Of course this is all speculation on my part, but I am just warning of the idea of picking one natural thing at a time -- natural things go together.
Using soap has a big effect on how the UV light hits your skin, the damage it might cause, and the benefits that it might have. Of course this is all speculation on my part, but I am just warning of the idea of picking one natural thing at a time -- natural things go together.
Maybe instead of sunscreen, we should be using mudpacks. :) I think it might hurt my chances of getting employed, unless I worked only remotely. Also, my wife would have words.
However, anecdotally, the "mud beggars" at modern Renaissance Faires are said to have healthy skin. It could be a confusion of cause and effect, though.
However, anecdotally, the "mud beggars" at modern Renaissance Faires are said to have healthy skin. It could be a confusion of cause and effect, though.
Do consider that your ancestors developed in a particular latitude in a particular climate. E.g. anglo-saxons developed in northern latitudes & have pale skin. The fact that they spent many hours a day in the sun unprotected does not mean that an anglo-saxon would be advised to do the same in Phoenix.
Absolutely. I do think that the typical amount of sun which a descendant of northern Europeans, now living in Phoenix, gets is probably still not as much as their ancestors got, simply because the amount of time spent outside is so much less. But your point is well taken.
Also, most descriptions of our ancestors show them to have been far more hairy than we are.
I think there's a business opportunity for someone to make light bulbs which emit a little UVB. Not enough to cause sunburn or raise skin cancer risk, just enough to keep our vitamin D levels up. That way you could just stick it in a light fixture and go about your normal life. Is such a light practical to build?
There are plenty of tanning (UVB) lights at all different wattages available for purchase.
I think the problem is the visible light output tends to be harsh, and the bulbs are highly inefficient, they are exensive, and they don’t last very long either.
So there would be a lot of problems to solve, not the least of which is the cultural issue you raise of scaremongering around UVB exposure in the first place.
I think the problem is the visible light output tends to be harsh, and the bulbs are highly inefficient, they are exensive, and they don’t last very long either.
So there would be a lot of problems to solve, not the least of which is the cultural issue you raise of scaremongering around UVB exposure in the first place.
There is one FDA approved vitamin D lamp made by Sperti.com. Costs about $400, has a 5 minute timer, instructions say to use it once every other day, the UVB spectrum of the lamps is tailored to Vitamin D production. I have one, it works better than pills.
For those curious about the lamp, this is the link: https://www.sperti.com/product/sperti-vitamin-d-light-box
They used to sell these (as regular-size fluorescent tubes) decades ago.
Or just replace window glass with OP4 plastic. Not cheap.
I try to use a tanning bed a couple times a week in winter.
I think we need to update GTL: Golang, tan, laundry.
is that safe?
Tanning beds are banned in some countries with high skin cancer rates for good reason. It is a lottery and you are accumulating risk with exposure. I strongly suspect (without any real evidence) that there are a number of beneficial health effects to moderate UV exposure that can improve quality of life for some people but the experience with fair skinned populations in high UV parts of the world has been overwhelmingly negative. The public health advice is basically written in blood on this topic and so I would view people and sites promoting alternative views with an appropriate amount of skepticism for now.
Not at all.
I agree that food doesn’t have enough vitamin D, but supplements really made the difference for me. Just get the right dosage (which is probably higher that you think).
[deleted]
Were you measuring in observed serum vitamin D levels, or just in subjective wellbeing? Light therapy fixes Seasonal Affective Disorder but doesn’t necessarily do so by increasing vitamin D production.
Could I ask what lamp you chose and how long you spend in front of it? I take a fairly high dose of D3 and I'd be curious to try artificial light. Thanks!
Androv 3000 uv-b lamp for vitamin d.
I never use it for more than 1 minute and I alternate between facing away and towards it. For the first month I used it every day, now more like every other day or every two days.
I never use it for more than 1 minute and I alternate between facing away and towards it. For the first month I used it every day, now more like every other day or every two days.
Tangentially related, I got an androv full-spectrum lamp several years ago for some color work. It was one of the few true "full spectrum" bulbs you can get for cheap which are decently balanced without resorting to use a combination of bulbs. And yes, we tested it with a spectrometer.
Most other full-spectrum lamps I tried at the time on amazon didn't get even close.
If you never tried, working with these lamps is weird: turning it on in the evening or night by mistake _really_ wakes you up.
So yeah, I hope Androv kept up with the quality.
Most other full-spectrum lamps I tried at the time on amazon didn't get even close.
If you never tried, working with these lamps is weird: turning it on in the evening or night by mistake _really_ wakes you up.
So yeah, I hope Androv kept up with the quality.
Maybe I should replace my daylight lamp with this, to counter the winter depression. (Norwegian).
Was that the desklamp? Do you happen to know a more specific model of such a lamp?
Yes, to be specific the 42W model.
I did the order in 2010, to be specific, so some time has passed since I did the tests.
>... now more like every other day or every two days.
Can I ask the difference? I'm assuming a typo, but haven't experienced sun shortage for at least six years, so I'm not sure on boom / bust cycle potential with these things.
Can I ask the difference? I'm assuming a typo, but haven't experienced sun shortage for at least six years, so I'm not sure on boom / bust cycle potential with these things.
I dont understand the question. The difference between using every other day or every two days?
Are these lamps safe?
A few applications à 15 min with a mercury high pressure lamp with a good reflector and you look like you went to the Caribbean for holidays. Maybe add a filter for UV-C, but there is no ionizing radiation. Just show any lamp in question to your favorite dermatologist. If he seems unhappy, you have the chosen the right lamp.
Jokes aside, skin is very photo-active and I do think lamps can help greatly against these kind deficiencies.
Most lamps emit a line spectrum though, so it is not like real sunlight. I wonder if that is the reason people going to solaria often seem to have weird skin tones. Ask a dermatologist and don't forget eye protection.
Apart from that it has the same side effects as sun exposure. Too much leads to skin aging, sunburn, cancer, etc.
Jokes aside, skin is very photo-active and I do think lamps can help greatly against these kind deficiencies.
Most lamps emit a line spectrum though, so it is not like real sunlight. I wonder if that is the reason people going to solaria often seem to have weird skin tones. Ask a dermatologist and don't forget eye protection.
Apart from that it has the same side effects as sun exposure. Too much leads to skin aging, sunburn, cancer, etc.
Those side effects can be mitigated or at least reduced by adding extra infrared or red light. Eg sunburns are prevented or greatly reduced by treating with near infrared either before or after UV exposure.
Could you explain please how/why IR helps with sunburn? :o
There are some interesting papers turning up if you google „pubmed infrared sunburn“. One of these: https://link.springer.com/article/10.1007/BF00373376
A related anecdote:
I dabbled in light therapy and found the first lamp I tried [1] very effective. However I have also started receiving comments from my colleagues about my nice new facial tan, in the dead of winter. I freaked out because the lamp was in my field of view 30 minutes per day every day without any eye protection, and sent the lamp back to where I bought it. Subsequently I have tried three different LED-based lamps and they seem to have no effect. I have carefully measured the light output and placed myself at proper distance to get the requisite 10,000 lux in all cases. No dice.
Here's the kicker - that lamp [1] appears to be the one used in some of the light therapy research (that's why I got it). It is entirely possible that much of light-therapy research was contaminated by badly designed lamps. There is no FDA certification for any of this as far as I know.
[1] Carex Day-Light Classic Plus Bright Light Therapy Lamp. Supposedly UV-filtered.
I dabbled in light therapy and found the first lamp I tried [1] very effective. However I have also started receiving comments from my colleagues about my nice new facial tan, in the dead of winter. I freaked out because the lamp was in my field of view 30 minutes per day every day without any eye protection, and sent the lamp back to where I bought it. Subsequently I have tried three different LED-based lamps and they seem to have no effect. I have carefully measured the light output and placed myself at proper distance to get the requisite 10,000 lux in all cases. No dice.
Here's the kicker - that lamp [1] appears to be the one used in some of the light therapy research (that's why I got it). It is entirely possible that much of light-therapy research was contaminated by badly designed lamps. There is no FDA certification for any of this as far as I know.
[1] Carex Day-Light Classic Plus Bright Light Therapy Lamp. Supposedly UV-filtered.
How is a Vitamin D lamp supposed to promote the creation of Vitamin D without UV?
It only blocks most of the UV. The lamp itself is blasting a very intense amount of light, so that the circadian-sensitive mechanisms in your eyes are fooled into thinking you're outside on a bright summer day. The vitamin D is secondary to the main function of the lamp, which is to be incredibly bright in comparison to most indoor lights. The light-therapy lamp must be aimed at the eyes (even for blind people!). It just doesn't work as well if you can't see it directly. You would have to pump even more light into the room to get the same amount reflected off of other surfaces.
Also, the lamp could be putting out UVA and not much UVB, so it could tan without producing much vitamin D.
For just the vitamin D, I'd get a "5.0" UVB lamp in a bare-bulb fixture, designed and sold for indoor avian and reptile pets. Aim at arms and hands, and away from the eyes. They're about $15 per bulb, and should be replaced every 6 months, as the UVB output degrades over time. Afterward, they work perfectly fine as compact fluorescents, behind glass or under lampshades, for several more months, albeit shaped inconveniently for some fixtures.
A "10.0" bulb is for desert-species pets. The UV output is too high for the overall lamp brightness, and may damage your eyesight, as human pupils don't constrict enough. I suppose you could wear sunglasses, but that seems counterproductive to just buying a lower-UV lamp.
Also, the lamp could be putting out UVA and not much UVB, so it could tan without producing much vitamin D.
For just the vitamin D, I'd get a "5.0" UVB lamp in a bare-bulb fixture, designed and sold for indoor avian and reptile pets. Aim at arms and hands, and away from the eyes. They're about $15 per bulb, and should be replaced every 6 months, as the UVB output degrades over time. Afterward, they work perfectly fine as compact fluorescents, behind glass or under lampshades, for several more months, albeit shaped inconveniently for some fixtures.
A "10.0" bulb is for desert-species pets. The UV output is too high for the overall lamp brightness, and may damage your eyesight, as human pupils don't constrict enough. I suppose you could wear sunglasses, but that seems counterproductive to just buying a lower-UV lamp.
These "light therapy" lamps don't. They just supposedly improve mood from the exposure to bright light itself and don't claim to produce vitamin D.
LED lamps do not emit any UV unless you specifically order ones that do. Fluorescent lamps put out more UV by comparison!
Do LED lamps not produce light via blackbody radiation? If they do then they must produce at least some UV
> Do LED lamps not produce light via blackbody radiation?
I'm pretty sure the answer to that is that they do not.
I'm pretty sure the answer to that is that they do not.
No, they use electroluminescence, not incandescence.
>was a world changer within days
Question, what were your health issues and what changes did you see that quickly?
Question, what were your health issues and what changes did you see that quickly?
Magnesium deficiency and a general mineral imbalance that resulted in severe insomnia. I also developed a bunch of food intolerances that were getting ever worse.
I was supplementing with a lot of magnesium. Sleep returned very quickly, my need for supplementing magnesium also dropped in days.
I was supplementing with a lot of magnesium. Sleep returned very quickly, my need for supplementing magnesium also dropped in days.
How were you measuring magnesium need, blood tests?
After reading the "Big Vitamin D Mistake" article on HN in 2017 I also started experimenting with larger doses of Vitamin D and can attest to life-changing effects.
It has been like a permanent +5 to constitution; I am now almost through my second winter without getting sick, something inconceivable for me as a kid growing up with asthma and a whole range of puffers, and always prone to debilitating sinus infections that told hold in January and never really let up sometime around April.
It has been like a permanent +5 to constitution; I am now almost through my second winter without getting sick, something inconceivable for me as a kid growing up with asthma and a whole range of puffers, and always prone to debilitating sinus infections that told hold in January and never really let up sometime around April.
That is amazing. What kind of vitamin D in at what levels did you settle on?
I initially started with 1000 IU of Vitamin D3, Costco brand, and eventually settled on 5000 as I noticed improvements in energy level as I took more.
I am at 43 latitude so I only start taking it in mid-November and start weening myself off it in late March (you never really know if/when spring will happen up here in Toronto :)
I am at 43 latitude so I only start taking it in mid-November and start weening myself off it in late March (you never really know if/when spring will happen up here in Toronto :)
Thank you,
Couldn't it be that this depends on the person? Maybe others can use the vitamin D present in food? I.e. part of your deficit might be because your body somehow cannot process the D in food? Just guessing here..
Narrowband uvb is a very effective treatment for some skin conditions. The mechanism is totally different to vitamin D and oral supplementation basically has no effect. UV exposure is a significant health risk in some parts of the world and the public information campaigns to reduce exposure seem well justified. But I wonder if there isn't a case for a narrowband uvb sunscreen that only lets those dangerous but highly effective dna mutating rays through along with some sort of cheap and reliable dosimetry.
I live in Southern California and it's common for people to have these effects when moving here from darker locales and spending time outside. My severe insomnia almost vanished after coming here.
And here I was thinking I was OK because I drink vitamin D supplemented whole milk.
Those concerned about low vitamin D levels can get more of the vitamin through foods.
Supplementing with D3 had very limited effect.
Non sequitur. Pills are not food.
Supplementing with D3 had very limited effect.
Non sequitur. Pills are not food.
Which lamp do you use?
It's like the old Klingon proverb: People who live in glass houses should upgrade to transparent aluminum.
It's not about us, UV light destroys almost all types of plastic materials, and affects color of wood and fabrics - so without glass UV filtering our furniture, floors and pretty much everything else inside our houses and cars that is exposed to sunlight would last a lot shorter.
I wonder why Vitamin D level blood test is unusually expensive than other blood test . It doesn't even get covered by CBP ( complete blood picture )
capitalism
UVB is required for health and carcinogenic?
It's been 500 years since Paracelsus supposedly said something along the lines of: "All things are poison, and nothing is without poison, the dosage alone makes it so a thing is not a poison."
https://en.wikipedia.org/wiki/The_dose_makes_the_poison
https://en.wikipedia.org/wiki/The_dose_makes_the_poison
Welcome to unintelligent design.
Evolution will happily incorporate an abundant resource into one biological process even if it is damaging to another. Heck, even if it is damaging to the same process it is being incorporated into.
Evolution will happily incorporate an abundant resource into one biological process even if it is damaging to another. Heck, even if it is damaging to the same process it is being incorporated into.
The heat we produce in oil motors is what makes them work, but it's also what destroys many components. I don't pretend life has been designed or not, but it doesn't look stupid to me: in a relative world, everything is a compromise.
It's far worse than the trade-offs required by physics.
Evolution is short-sighted in a way that is hard to overstate. It exclusively cares about the current environment, it can only consider alternatives when they have actually been implemented, it can't look-ahead to see if a chain of changes is really desirable, and it can't even look-behind to determine if a previous design is better-suited to the current environment.
A better analogy to the way evolution operates using an engine would be: imagine that you first develop an engine that runs on a pure fuel, but then for a long span of time you can only get an inferior, highly contaminated fuel that produces a corrosive acid while it burns that slowly destroys the engine from the inside. You make a few tweaks to mitigate (but not stop) the damage from the acidic residue, but then you discover that by adding an additional afterburner with a special additive, you can get an extra 8% output from the engine. But then later when the pure fuel is available again, you discover that running the engine with the afterburner on a pure fuel will make it explode in short order. It's too late to redesign the engine without the afterburner -- most of the engines currently in existence suffer from the problem -- but it's pretty easy to re-contaminate the pure fuel so that it continues to produce the acidic residue that is both destroying the engines and expected by the afterburners. Meanwhile, most people still don't want to buy a pure-fuel engine without the afterburners since they have a lower output, and you really don't need most engines to last forever anyway.
That's the sort of bullshit you deal with in an evolved system.
Evolution is short-sighted in a way that is hard to overstate. It exclusively cares about the current environment, it can only consider alternatives when they have actually been implemented, it can't look-ahead to see if a chain of changes is really desirable, and it can't even look-behind to determine if a previous design is better-suited to the current environment.
A better analogy to the way evolution operates using an engine would be: imagine that you first develop an engine that runs on a pure fuel, but then for a long span of time you can only get an inferior, highly contaminated fuel that produces a corrosive acid while it burns that slowly destroys the engine from the inside. You make a few tweaks to mitigate (but not stop) the damage from the acidic residue, but then you discover that by adding an additional afterburner with a special additive, you can get an extra 8% output from the engine. But then later when the pure fuel is available again, you discover that running the engine with the afterburner on a pure fuel will make it explode in short order. It's too late to redesign the engine without the afterburner -- most of the engines currently in existence suffer from the problem -- but it's pretty easy to re-contaminate the pure fuel so that it continues to produce the acidic residue that is both destroying the engines and expected by the afterburners. Meanwhile, most people still don't want to buy a pure-fuel engine without the afterburners since they have a lower output, and you really don't need most engines to last forever anyway.
That's the sort of bullshit you deal with in an evolved system.
> Evolution is short-sighted in a way that is hard to overstate. It exclusively cares about the current environment
This isn't quite accurate; while some evolutionary pressures are indeed exclusively short-term, not all are.
For instance, ability of eukaryotes to have multiple alleles of individual genes combined with sexual reproduction allow populations to maintain a large diversity of alleles and genes, which have the effect of allowing large-scale "split testing" and also "alternatives" for different current environments that may appear over time.
This isn't quite accurate; while some evolutionary pressures are indeed exclusively short-term, not all are.
For instance, ability of eukaryotes to have multiple alleles of individual genes combined with sexual reproduction allow populations to maintain a large diversity of alleles and genes, which have the effect of allowing large-scale "split testing" and also "alternatives" for different current environments that may appear over time.
What else could you hope for?
It seems like you'd like for evolution to have some model, so it can test old designs in the current environment, and simulate forward the current design into future environments, without needing to burn an organism and time on the test. But how could that be possible?
It seems like you'd like for evolution to have some model, so it can test old designs in the current environment, and simulate forward the current design into future environments, without needing to burn an organism and time on the test. But how could that be possible?
By evolving intelligence that creates computers and models and does that exact simulation, and then modifies the necessary biology to apply the best scenario. Seems to me we’re well on our way there.
>in a relative world, everything is a compromise.
Modern men call it: "There is no free lunch!"
Modern men call it: "There is no free lunch!"
Well, evolution doesn't care if you die at 50 from sun induced cancer or at 80 from heart failure, as long as you've pumped out offsprings capable of reproduction you succeeded.
Plus nowadays with tech / medical advances evolution doesn't play the same role as 10k years ago. You can be obese, diabetic, lactose intolerant, lose a kidney and a lung and still get kids + your life expectancy will be miles ahead of our ancestors hunting antelopes with spears and pointy stones.
Plus nowadays with tech / medical advances evolution doesn't play the same role as 10k years ago. You can be obese, diabetic, lactose intolerant, lose a kidney and a lung and still get kids + your life expectancy will be miles ahead of our ancestors hunting antelopes with spears and pointy stones.
This is a commonly-held misunderstanding! Natural selection doesn't stop acting once you've reproduced.
Characteristics ("traits") which are potentially not helpful for direct reproductive success but have an impact on the success of the group of people you're a part of are conserved through evolution. However, the exact formulation of this idea (known as kin selection or group selection) is still quite controversial [1] among evolutionary biologists.
[1]: https://blog.oup.com/2015/01/kin-group-selection-controversy...
Characteristics ("traits") which are potentially not helpful for direct reproductive success but have an impact on the success of the group of people you're a part of are conserved through evolution. However, the exact formulation of this idea (known as kin selection or group selection) is still quite controversial [1] among evolutionary biologists.
[1]: https://blog.oup.com/2015/01/kin-group-selection-controversy...
Sure, it depends at which scale you observe it. It's probably impossible to study individual traits vs "group" traits though. As I see it it's one of these problems with so many co-founding variables that we'll never agree (depending on who you listen to: fat is good/bad, carbs are good/bad, sun is good/bad, ad infinitum)
My point was, something can be good at some point (vitamin D production) and turn bad in the long term (increased cancer rate), but being ultimately bad doesn't mean evolution failed.
My point was, something can be good at some point (vitamin D production) and turn bad in the long term (increased cancer rate), but being ultimately bad doesn't mean evolution failed.
Yes. Otherwise there would be no reason to live as long as we do.
Maybe the intelligence behind the design was to make something that works, instead of something perfect? Isn't that better, after all?
(Also is there even any indication anywhere that a perfect thing is possible at all, whether be by design or a result of random chaotic process?)
(again, not saying whether the design might be intelligent or not, just that the argument is not really logical concerning that).
> Welcome to unintelligent design.
Or just designed for another purpose.
Or just designed for another purpose.
This and periods which are unique to humans (I think) are classic examples of evolution hackery.
> unique to humans
It appears not - http://www.bbc.co.uk/earth/story/20150420-why-do-women-have-...
> Apart from humans, most of the other menstruating animals are primates, the group that includes monkeys and apes as well as humans. Most monkeys living in Africa and Asia, such as rhesus macaques, menstruate.
> menstruation also evolved independently in two other groups: some bats and elephant shrews.
Not that any of this disproves the "evolution hackery" suggestion, mind.
It appears not - http://www.bbc.co.uk/earth/story/20150420-why-do-women-have-...
> Apart from humans, most of the other menstruating animals are primates, the group that includes monkeys and apes as well as humans. Most monkeys living in Africa and Asia, such as rhesus macaques, menstruate.
> menstruation also evolved independently in two other groups: some bats and elephant shrews.
Not that any of this disproves the "evolution hackery" suggestion, mind.
Thanks. I was not 100% on it being unique to humans but I did remember it being quite rare in nature.
Similarly, water hydrates and drowns. Moderation is often a necessary principle.
Moderation may not suffice. I'd say Dihydrogen Monoxide is very dangerous given it's a colorless and odorless chemical compound so not always easy to identify for the layman. Yet we can spot it in great quantity in most food despite the fact it's PH is higher than most acids. You can't even wash it off at the sink, the more you do, the more you get in contact with it.
I mean at least UVB, you can protect against with simple glass. But something you find traces in most people's blood is no joke.
We should suppress it completly. Or at least ban it from schools.
I mean at least UVB, you can protect against with simple glass. But something you find traces in most people's blood is no joke.
We should suppress it completly. Or at least ban it from schools.
See: Oxygen.
Required for us to stay alive, yet ultimately kills us.
Required for us to stay alive, yet ultimately kills us.
What likely happened is, since humans started living on the ground after they left trees, they had enough sunlight exposure; so we evolved sunlight to be a start marker for some important metabolic activities, purely by randomness. It just so happens that too much sunlight exposure causes cancer. But since cancer happens later in life, it wasn't selected against and we just ended up with this weird biochemistry: UVB is necessary for health but it also causes cancer.
Is it required, though? If you don't get it through diet, sure.
water, a building block of life, can kill you
Don't downvote OP, it's a very legitimate question.
Medias tend to represent everything as black and white, and so it's easy to get confused, espacially since people will tell you everything then the contrary depending of the fashion of the day.
It's always nice to have those moments, when you can highlight that reality has nuances. Let's encourage people asking for answers, we don't have enough of them.
And yes, Vitamin D is required, not UVB. You can aquired vitamin D by eating organisms full of it. But the most efficient way is still to get exposed to sunlight. It's partly why some get depressed in the winter.
The sun is not "bad for the skin" any more than a cold water is bad for your health. But stay in it too long and you may die.
Medias tend to represent everything as black and white, and so it's easy to get confused, espacially since people will tell you everything then the contrary depending of the fashion of the day.
It's always nice to have those moments, when you can highlight that reality has nuances. Let's encourage people asking for answers, we don't have enough of them.
And yes, Vitamin D is required, not UVB. You can aquired vitamin D by eating organisms full of it. But the most efficient way is still to get exposed to sunlight. It's partly why some get depressed in the winter.
The sun is not "bad for the skin" any more than a cold water is bad for your health. But stay in it too long and you may die.
> And yes, Vitamin D is required, not UVB. You can aquired vitamin D by eating ...
There is some debate about this now, while sunlight certainly produces vitamin D, that's certainly not all that it does. This article showed up here recently:
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
There is some debate about this now, while sunlight certainly produces vitamin D, that's certainly not all that it does. This article showed up here recently:
https://www.outsideonline.com/2380751/sunscreen-sun-exposure...
Of course, but sunlight is not just UVB. Plus, the spectrum of one component is hardly what define light interraction. The many spectrums + quantity + intensity + the human receiving is a more interesting model.
E.G: I just bought a light to help with the winter blues. It does not provide any UVB, so the method of action is something else.
E.G: I just bought a light to help with the winter blues. It does not provide any UVB, so the method of action is something else.
Worth saying that for fellow British users we won't be able to get any vitamin D from the Sun until mid March. We live at too high a latitude - the sun is too low down in the horizon.
On the other hand UV tends to lower your folate levels. Populations' skin colors tends to track the latitudes they live in but also the ratio of vitamin D to folate in their diets. That's part of the reason the pre-agrigultural population of Europe with their fish heavy diet had skin colors so much darker than modern Europeans
https://www.bbc.com/news/science-environment-42939192.
https://www.bbc.com/news/science-environment-42939192.
I've noticed plants do poorly behind windows at my office (thick glass, newer glass) despite being South facing (northern hemisphere). At home in a windowsill behind glass from the 60s they thrive.
Anyone had a similar experience? Think it could be because of the office glass?
Anyone had a similar experience? Think it could be because of the office glass?
Office glass is heat-shielded to reduce AC costs. That's be my guess - lack of IR.
I think it's more likely that they don't like the warm dry air produced by the radiators that are typically installed below the windows. Chlorophyll doesn't absorb much UV.
I have a lemon tree that is indoors in full sun. Last summer I put it outdoors for the first time and it has 3-5x more foliage than it has ever had.
My newborn daughter's pediatrician recently told my wife and I how important it is to sit in front of the window with our daughter, specifically for vitamin D generation via sunlight exposure (as opposed to taking her outside right now because it's very cold/winter). I guess I (and perhaps all parents of winter babies?) should ask about a vitamin D supplement.
or just go outside with your baby. humans are pretty resilient, especially the rubbery little ones and they are really good at telling you when they are uncomfortable.
Sunlight does not provide enough UVB for sufficient vitamin D production above a surprisingly low latitude (35N) during the winter months.
https://www.nytimes.com/2018/02/16/well/live/do-i-get-enough...
https://www.nytimes.com/2018/02/16/well/live/do-i-get-enough...
Great to know! I just started supplementing vitamin D this year in New England, and it seems like it's really helpful.
I think a big part of my point was about the resiliency of children. It's worrying that new parents are scared to experience the world with their children.
I think a big part of my point was about the resiliency of children. It's worrying that new parents are scared to experience the world with their children.
New parents are still getting up to speed on what is a real danger and what isn't. There are plenty of legitimate dangers that require consideration, as well as scary things that are in fact perfectly fine.
This is a common trait of new parents. It weans off; quickly for most.
as a new-ish parent, i'd love to get my kids outside to soak up sunlight but it's nearly impossible to stay outside for any meaningful amount of time in the northeast winter.
I've seen parents schlep <1 year old babies up some of the White Mountains in mild winter conditions (snow on the ground, below 32F, etc). I think you are doing something wrong.
ignoring the glass - in the winter much of the US is at too high a lattitude to get any UVB, as it bounces off the atmosphere because the angle of attack is too shallow. The sun needs to be at least 50degrees above the horizon for UVB to penetrate the atmosphere. In an iowa winter, even at its apogee the sun is only ever 26deg above the horizon
You should definitely check out a Vitamin D supplement for your daughter. Where I am from we have reduced sunlight during winter months and it is something all the pediatricians have recommended and asked if we are doing because of the lack of sunlight.
How much cold is 'very cold'?
Or look for another pediatrician!
I agree with the other comments, isn't this common sense and known? I have been told this when I was a kid.
The one thing I learned in college was that schools outside of my state are pretty bad with "common sense".
"Common sense" is highly localized. My schools had health studies for sure, but no home economics. I had classmates in college who had home economics, but not very robust health classes.
Any and all combinations of learning exist in the USA alone. Each State is in charge of its own education department. Travel just 2 or 3 states in any direction, and you'll have a grossly different set of skills being taught at the high-school level.
"Common sense" is highly localized. My schools had health studies for sure, but no home economics. I had classmates in college who had home economics, but not very robust health classes.
Any and all combinations of learning exist in the USA alone. Each State is in charge of its own education department. Travel just 2 or 3 states in any direction, and you'll have a grossly different set of skills being taught at the high-school level.
Common sense is wrong as often that it's right, being told something as a kid doesn't help either since you're less likely to question the source.
Yeah of course, there are many things that are widely believed but are false. But we were told this in a 30 minutes course a doctor was giving, in a campaign the schools were doing to educate us about the danger of the sun. A few other things were told, like that there is no total protection sun cream or that even cream that are marked as water resistant do not resist water. That's when we learned that 1mm of "modern glass" would cut nearly all uv light, while it requires nearly 50 meters of water to block it.
Of course not all that might be true, but as far as I know, it is pretty accurate.
Of course not all that might be true, but as far as I know, it is pretty accurate.
As I mentioned in another comment I was aware of this fact. I would have been able to tell you as such if someone had asked, but Vitimin D would never have crossed my mind as being an issue.
Thought the same thing, I thought this was common knowledge. But I live in the upper midwest where low D levels are common in winter, so perhaps it's just discussed here more.
I did not know this, but I also didn't grow up in the US.
I was aware of this, but it never crossed my mind that this fact might be causing problems for me.
I realize now just how little sunlight I get. I probably spend less than 5 minutes outside a month as I only go from indoors to indoors by car.
I realize now just how little sunlight I get. I probably spend less than 5 minutes outside a month as I only go from indoors to indoors by car.
Does anyone know of any instruments you can use to measure uva and uvb?
You can build your own, https://makezine.com/projects/build-hack-and-deploy-detector...
Or buy one https://www.solarmeter.com/model65.html
Or buy one https://www.solarmeter.com/model65.html
When I lived at my parent’s place the following scene always was a bit odd during the winter months:
“Hey Mettamage, why is your window wide open? It’s freezing!”
“I need vitamin D.”
“Then why do you cover your body with a blanket?”
“It’s cold.”
“Hey Mettamage, why is your window wide open? It’s freezing!”
“I need vitamin D.”
“Then why do you cover your body with a blanket?”
“It’s cold.”
Also note: research on vitamin D has suggested that it’s not vitamin D that provides the benefits often touted, but the fact that you are outside getting exercise.
I get my vitamin D levels check every quarter because of my kidney failure. Based on my past experiments, I'd say if you are in the bay area, walking in the noon sun for 15 minutes every workday would be enough to keep healthy vitamin D levels. In terms of supplements, about 1500 IU/day is enough during winter season.
My personal experience with nutrition makes me consider the childhood years as the deciding factor in regards to living healthy without much time or resources allocated towards personal health. There are outliers, such as genetics and parenting will limit a child or not but I can only assume it’s a struggle starting unhealthy in the early to late 20s. All my childhoods friends that were into skateboarding, biking or another intense activity from sun rise to sunset cannot put on weight. Typically have healthy skin unless acne prone and are very coordinated with balancing. The reason this article compelled me to write is because the next generation of parenting is restricting kids from the freedom of outside activities unless a parent is there with the kids. There will be a lot of lacking factors besides vitamin D and it’s terrible to think about. I’ve been a person who has most of my life believed that deterrents should exist against parents who let there kids become unhealthy. It seems we’re heading the opposite direction.
Might you be confusing correlation and causality? Whatever caused your childhood friends to be into intense physical sports, might also be the cause of their adulthood health - perhaps a natural inclination to physical activity, or maybe an unusually fast metabolism that gives them lots of energy to burn.
Not to suggest that you're wrong - childhood exercise probably is very important, and is under threat.
Not to suggest that you're wrong - childhood exercise probably is very important, and is under threat.
Has anyone used the Sperti UVB vitamin D lamp?
https://www.sperti.com/product/sperti-vitamin-d-light-box
It appears to be the only FDA approved one.
It appears to be the only FDA approved one.
It is FDA cleared rather than approved, which is a lower bar. And it appears to be cleared as a tanning device, not as a Vitamin D-related device:
https://www.accessdata.fda.gov/cdrh_docs/pdf15/K151721.pdf
Note that the manufacturer has gotten in trouble with the FDA before:
https://www.fdalabelcompliance.com/letters/ucm284022
So I'd maintain some skepticism on the product's efficacy as it related to health. (I tried finding other clearances related to the product and failed, but they might still be out there...)
https://www.accessdata.fda.gov/cdrh_docs/pdf15/K151721.pdf
Note that the manufacturer has gotten in trouble with the FDA before:
https://www.fdalabelcompliance.com/letters/ucm284022
So I'd maintain some skepticism on the product's efficacy as it related to health. (I tried finding other clearances related to the product and failed, but they might still be out there...)
Interesting. Thanks for the information!
Eventually all artificial lights that don’t help with vitamin D deficiency should be banned.
it's interesting how UVB also modulates eye growth (and myopia) - https://jamanetwork.com/journals/jamaophthalmology/fullartic...
"After adjusting for high levels of education, a well-established risk factor for myopia, they found that participants with the highest UVB exposure, especially in the teenage and young adult years, had about a 30% lower risk for myopia than those with the lowest exposure. The study also found no association with myopia and vitamin D levels or genetic variants in Vitamin D."
"After adjusting for high levels of education, a well-established risk factor for myopia, they found that participants with the highest UVB exposure, especially in the teenage and young adult years, had about a 30% lower risk for myopia than those with the lowest exposure. The study also found no association with myopia and vitamin D levels or genetic variants in Vitamin D."
Have never used one of these, but have heard good things about lamps from https://www.circadianoptics.com/ from friends living in high latitudes.
Be careful not to have vitamin D deficiency! I think that might have been one of things which contributed to my multiple sclerosis. I was sitting in front of pc most of the spring/summer, rarely spending time outside...
“It doesn’t matter if it’s winter or summer, you will make no vitamin D sitting in front of a window"- this is a true statement.!
I've known about glass inherently blocking UV for a long time, but have wondered why do posters, etc. fade in store windows.
Simple solution. Open the window in your house or in your car while you driving. You will then get direct exposure to the sun!
tldr: no.
The article mentions commercial and automobile glass. What about forty year old double pane glass in an old house? On very cold winter days in Vermont I enjoy a kitchen bathed in sunlight. No benefit?
eddd(2)
Isn’t this common sense?
Common sense is, if I can see the sun through it unblocked, it must let light through, and light gives me vitamin D, right?
Common sense is a function of individual's level of knowledge. For vast majority of people, "common sense" would dictate answering this question "yes", even though in reality, the answer is "no".
I knew about this - and I think that if you have had a deficiency of Vitamin D your doctor might have told you about it.
But I'd wager to say the majority of the population that didn't consult a doctor due to a deficiency won't know this. (Unless, perhaps, when they studied something in the medical field).
But I'd wager to say the majority of the population that didn't consult a doctor due to a deficiency won't know this. (Unless, perhaps, when they studied something in the medical field).
Who cares if it's common sense? Common sense is a very bad way to make conclusions.
How could the fact that glass blocks UVB but allows UVA and Light be common sense?
I think it's one of those things that should be common sense but we don't generally think about it hard enough. By that I mean everyone probably could figure it out if they just gave it about 30 seconds of thought. I clearly remember the day I learned this back in high school. My physics teacher was discussing the refraction of light in materials like water and glass and the conversation moved into how materials can break up the components of light (like a prism). Another student was trying to make sense of this concept of light breaking down into frequencies and its component parts but still be light after being broken down. Forcing us to think about it ourselves, the teacher asked the class two questions:
1) Have you ever gotten a tan anywhere on your body on a long car drive in the summer? Everyone thought for a moment and answered that they hadn't even gotten so much as a farmer's tan on their arm to which he asked...
2) Why?
This forced us to think about it and realize that the window was doing more than just refraction and was stripping out or absorbing part of the light and even though it appeared as the same light to us, whatever was being removed must have been in the spectrum of light not visible to humans.
So we all intuitively know this, but never stop to actually think about it.
This forced us to think about it and realize that the window was doing more than just refraction and was stripping out or absorbing part of the light and even though it appeared as the same light to us, whatever was being removed must have been in the spectrum of light not visible to humans.
So we all intuitively know this, but never stop to actually think about it.
Doesn't seem like much intuition was had in your example, to be honest.
The teacher primed you with "Why have you never gotten burned on a long summer drive?" and then you bought that as fact and backsplained it with some basic prism experiments, the backsplanation not really mattering once you buy the fact from the teacher.
In other words, I'm not sure what 30 second thought process you think the average person can walk through to replace a teacher telling you the fact outright.
Once you know a fact, people can "intuit" any explanation. Just talk to children and listen to their bizarre theories -- but I would not call that intuition because they cannot arrive at the original fact that way.
Besides, my intuition is the opposite. My friend was a truck driver and said he'd get sunburned hands. He always kept sunscreen in the cabin.
The teacher primed you with "Why have you never gotten burned on a long summer drive?" and then you bought that as fact and backsplained it with some basic prism experiments, the backsplanation not really mattering once you buy the fact from the teacher.
In other words, I'm not sure what 30 second thought process you think the average person can walk through to replace a teacher telling you the fact outright.
Once you know a fact, people can "intuit" any explanation. Just talk to children and listen to their bizarre theories -- but I would not call that intuition because they cannot arrive at the original fact that way.
Besides, my intuition is the opposite. My friend was a truck driver and said he'd get sunburned hands. He always kept sunscreen in the cabin.
My point was that once you learn the basic physics underlying this, you should be able to come to the proper conclusion about the vitamin D question easily enough. Every person going through the US school system is required to take a basic physics course, as far as I know. So every child who receives a HS diploma in the US should know this basic concept and, if they actually thought about it, should be able to figure it out.
I think you're confusing the underlying theory with us encountering the question on the day we learned it and then dismissing the fact that we were primed with the current conversation to know the answer. What I'm saying is that once we had that knowledge about the underlying physics, the same question(s) could have been posed weeks or months later (with no priming) and we should have been able to figure it out.
I think you're confusing the underlying theory with us encountering the question on the day we learned it and then dismissing the fact that we were primed with the current conversation to know the answer. What I'm saying is that once we had that knowledge about the underlying physics, the same question(s) could have been posed weeks or months later (with no priming) and we should have been able to figure it out.
I, for one, can't really think of any daily experiences that would count as evidence for or against glass being transparent to UV. Maybe if long drives in sunny weather are a typical experience to someone, it'll be common sense to them, but I'm rarely in a car for longer than couple of hours at a time and I develop tans gradually enough I can't really notice it in span of days, let alone hours. My answer to your teacher's question 1 would be "no idea" since I wouldn't have paid attention to it in the first place.
Of course, given a premise "skin doesn't tan when sitting in a car", I think it's a good explanation for the subject.
Of course, given a premise "skin doesn't tan when sitting in a car", I think it's a good explanation for the subject.
So in a physics class, while learning about refraction, you were primed with a fact that you hadn’t personally noticed before and from that experience you deduce that this should be common sense?
It's not that we hadn't noticed it before. It's that we hadn't thought about it before. We all knew from experience that none of us had gotten any sort of tan through glass when asked. We just never thought to think about why. And before that day, we didn't know enough to answer the question. The fact that we were "primed" is just happenstance because the question came up during the learning process. Once we knew the physics (which all HS students in the US learn), the same question(s) could have been asked on another day when we weren't "primed" with the discussion and we would have been able to deduce the answer. For example - if that anecdotal evidence never came up the teacher could have put it on the final exam and we should have been able to figure it out. Again, my point is that anyone who went through the US school system and theoretically has the capability of answering the question if they actually thought about it. But most don't. That was my only point, really. It should be common sense, but isn't because no one actually gives it any consideration.
I've occasionally posed this question to people during casual conversation, and I've always received the same answer - 'of course!' (... you make vitamin D behind glass).
It's still not clear to me if there are some types of glass that do allow vitamin D synthesis or not.
It's still not clear to me if there are some types of glass that do allow vitamin D synthesis or not.
From my understanding, UVB is required for vitamin D synthesizing by your body. If the glass blocks UVB then you're out of luck.
No.
Exactly what I was told as a child, and hence have 'known' for more than fifty years.
I was told that TV would turn my eyes square as a child, looking forward to having it proved by science so I can smugly announce that I've known all along.
Wait, no, it doesn't work like that.
Wait, no, it doesn't work like that.
No it doesn't. Therefore the quotes around 'known'.
Let us split the smugness down the middle.
Yes, I asked my science teacher this exact question when I was 15 (as I burn easily) and was happily told I couldn't get sunburnt behind glass. So far, experiments have proven this true.
I don't know if this counts, but there's picture of a truck driver which was doing the rounds:
https://www.nejm.org/doi/full/10.1056/NEJMicm1104059
https://www.nejm.org/doi/full/10.1056/NEJMicm1104059
A similar fact is that photochromic lenses will not work in cars, i.e. when you're looking at the world through the windshield. The photochemistry in them is triggered by UV rays. It's another thing that should be common knowledge, but isn't.
Unfortunately UVA contributes to skin cancer as well: https://www.skincancer.org/prevention/uva-and-uvb
Auto glass must be somehow different, because in Florida, you can surely get "some color" on your skin on a long drive and the sun beating in through the window.
Car windshields block UVA (because of their reinforcement materials to prevent dangerous shattering in an accident) but many side windows don’t.
Not sure if UVA could cause the “color” you describe. Supposedly only UVB causes tanning and sunburn. Might also just be a reaction to the heat?
Not sure if UVA could cause the “color” you describe. Supposedly only UVB causes tanning and sunburn. Might also just be a reaction to the heat?
Maybe it's due to heat made by Sun?
No. Definitely pink from slight burn. Google says some side windows aren't the same as the front and back.
1. Seasonal Affective Disorder is treated using just the visible light spectrum entering the retinas of the eyes [1], and there are a ton of studies showing its effectiveness (in fact, most SAD lamps explicitly filter out ultraviolet light).
2. Some infrared passes through some glass and seems to be good for a thousand different things. [2] [3]
3. UVA passes through glass and has beneficial effects on the cardiovascular system. [4]
[1] https://www.sciencedirect.com/science/article/pii/0273230092...
[2] https://valtsus.blogspot.com/2017/05/the-therapeutic-effects...
[3] https://www.quora.com/Can-infrared-light-pass-through-glass
[4] https://www.sciencedirect.com/science/article/pii/S0022202X1...