A recent Chinese study indicates that frequent exposure to bisphenol A, better known as BPA, may reduce a man’s testosterone level. The study focused on men who worked in a chemical plant and were exposed to BPA over the course of no less than six months. These men were found to have lower testosterone levels on average than their peers who worked in a factory that processes and bottles tap water.

Perhaps more importantly, the workers in the chemical plant were found to have lower levels of “free testosterone,” which is not bound to protein. This type of testosterone is most crucial to maintaining bodily functions, such as sexual functioning, related to testosterone levels. BPA is a chemical that is widely used in many food storage containers, especially plastic water bottles and canned foods.

The Link Between BPA and Sexual Hormones

According to research scientist Dr. De-Kun Li of Kaiser Permanente, one of the lead researchers behind the new study, the results add to a growing body of evidence indicating a link between BPA exposure and sexual hormone levels in men. A previous study involving factory workers in China indicated that frequent BPA exposure could lower a man’s sperm count while increasing his risk of sexual dysfunction.

Remarkably, BPA shares a similar chemical makeup with estrogen, often regarded as the female equivalent of male testosterone. Low levels of testosterone are found in women, just as low levels of estrogen are found in men. The researchers believe that the effects of BPA exposure on men are more obvious because their baseline estrogen levels are so low.

Should You Be Worried?

It’s important to remember that the study was conducted using subjects who worked full-time at a chemical plant, where the risk of BPA exposure was high and frequent. For those in the general population, exposure to BPA is less frequent. Still, BPA is found in many places to which the average person is regularly exposed, including the containers of most canned foods, some plastic food containers, and increasingly infrequently in certain plastic beverage containers. For this reason, pregnant women are often advised to limit their intake of canned food.

The vast majority of men would have undetectably low levels of BPA in their blood. However, 70% of those who worked in the chemical factory had measurable amounts of BPA in their bloodstream, while just 5% of male workers at the bottled water facility had the same.

Heather Patisaul, a BPA researcher at North Carolina State University, said that men shouldn’t worry about the study’s findings too much unless they work in a chemical factory. She also noted that the Chinese study was relatively small, and could include inaccuracies due to the samples being collected at non-specific times of the day. Testosterone levels rise and fall naturally during the day, which could have influenced the data.

The Bottom Line

A recent study indicates that frequent, prolonged exposure to BPA could reduce testosterone levels in men. However, the study was small, and it’s still difficult to say whether the average male is exposed to enough BPA to make a difference in his hormone levels.

The full text of the study can be found online in the medical journal Fertility and Sterility.