Could Female Hormones Contribute to the Obesity Epidemic?

A recent study conducted by researchers from Adelaide University's School of Medical Sciences examines how an imbalance of female sex hormones among men in Western nations could potentially contribute to higher levels of male obesity.

The study, published in the journal PLOS ONE, examines a potential link between exposure to substances containing the female sex hormone estrogen--including products with soy and plastics that are often found in more affluent societies.

Medical student James Grantham of the university and co-author professor Maciej Henneberg, Wood Jones, a professor of anthropological and comparative anatomy, compared obesity rates among men and women around the world with measures such as Gross Domestic Product in order to determine the impact of affluence on obesity.

They discovered that while it was typically normal in the developing world for women to have significantly greater obesity levels than men, the same issue was not always so common in the developed world. 

"Hormonally driven weight gain occurs more significantly in females than in males, and this is very clear when we look at the rates of obesity in the developing world," Grantham said, in a news release. "However, in the Western world, such as in the United States, Europe and Australia, the rates of obesity between men and women are much closer. In some Western nations, male obesity is greater than female obesity.

He added that while poor diet is certainly to blame, there may be more of an underlying issue than just higher caloric intake. 

"Exposure to estrogen is known to cause weight gain, primarily through thyroid inhibition and modulation of the hypothalamus. Soy products contain xenoestrogens, and we are concerned that in societies with a high dietary saturation of soy, such as the United States, this could be working to 'feminize' the males. This would allow men in those communities to artificially imitate the female pattern of weight gain," Henneberg added, in the release. "Another well-established source of xenoestrogen is polyvinyl chloride, known as PVC. This product is in prominent use in most wealthy countries, from plastic medical devices to piping for our water supplies."