Well fruits are not necessarily good for Tibetans. They have evolved their life style around their produce over thousands of years. It's like Europeans try to force Indians into a certain lifestyle.
Yes. In a country where even infant milk powder is tainted you can imagine what kind of food safety there is. Any those fish ponds, I bet a lot of them are polluted from industrial or agricultural contaminants. Unlike in US, the victim farmers usually cannot sue the polluters.