Around the world it is estimated that 1.4 BILLION individuals are overweight — a previously unknown problem in history, when food deprivation, famine, and day-long physical work were much more common. But why is this happening? Taking in too many calories does not explain the large amount of evidence.
In today’s PLOS ONE, James Grantham proposes “The estrogen hypothesis of obesity,” blaming the major obesity epidemic on “xeno-estrogens” in our environment. “Xeno” means “stranger,” and “xeno-estrogen” means estrogen coming from outside the body, specifically from plastics and many other products that push up estrogen levels in the body, and lower thyroid activity. The UK Daily Mail has a popular write-up of the scientific article.
Major sources of xeno estrogens are PVC’s (in plastic water pipes), soy foods, including soy bean protein added to other foods, soy added to vegetable oil and in some cheeses.
The researchers point to a possible “feminization” in prosperous cultures that have plenty of food – which now includes fast-developing countries like India and China.
First, this is an HYPOTHESIS. It needs more study.
Second, estrogen levels in the blood stream are MEASURABLE. So the hypothesis can be tested.
Third, it is easy to test the xeno-estrogen hypothesis in animals, where diet can be completely controlled.
We should get more evidence on this interesting hypothesis very quickly. If it is true, it might require huge investments in reducing soy in human diets, and replacing PVC pipes, or blocking xeno-estrogens in PVC products.