Should Women Hoping to Become Pregnant Eat More Soy?
We’ve all seen scary headlines linking bisphenol A (BPA) to a wide array of health problems. However, rigorous reviews of hundreds of BPA studies by the European Food Safety Authority and U.S. Food and Drug Administration emphasize BPA poses no health risk to consumers of any age as it’s currently used.
For those who still fear BPA, the substance is difficult to avoid—you’ll find it in plastics (to make them stronger) and in the lining of canned foods (to keep them from spoiling). Now, a new study suggests that women may be able to “protect” themselves from BPA simply by eating more soy.
The study, published in the Journal of Clinical Endocrinology & Metabolism, examined the BPA levels, diet, and in vitro fertilization success rates of 239 women in Massachusetts. The study’s authors found that compared with women who had low levels of BPA, women with a high level of BPA who did not eat soy foods had fewer pregnancies and live births. The study found that for women who regularly ate soy, BPA had no impact on their IVF outcomes.
But before you rush out to buy tofu and soymilk, let’s look a bit more closely at the study.
- There’s no strong evidence suggesting BPA exposure affects female fertility. The European Food Safety Authority’s panel examined three studies that authors claim show a link between low-dose BPA exposure and reduced fertility in rats. The Panel concluded that the studies did not show BPA exposure had a relationship to fertility. Additionally, a small study linking BPA concentration and IVF success has not been successfully replicated. As a result, EFSA found that the small size prevented “any conclusions to be drawn in the absence of data replication.” Even the authors of this study note there is “little evidence of associations between urinary BPA concentrations and adverse reproductive and pregnancy outcomes among women undergoing infertility treatment with assisted reproductive technologies.”
- The experiment did not randomly divide women into soy- and non-soy eating groups, but relied on women to self-report their diets. It’s well-documented that studies asking individuals to self-report their diets based on questionnaires aren’t very accurate. By not dividing the women into even groups, one which ate soy and one that did not, the researchers were left very uneven groups. 74% of the women in this study consumed soy foods—that means only 61 women in the study did not consume soy, an extremely small sample.
- The study failed to prove either that BPA influenced fertility or that it was soy (and not other factors) that actually improved fertility outcomes. The study’s results certainly do not prove causation between eating soy and successful IVF treatments.
Unsurprisingly, media coverage of this study neglected to include these important caveats. Instead, reporters used inaccurate and misleading headlines such as, “Soy-rich diet protects women from BPA health risks.”
Fertility is extremely complex and there are myriad factors in why some IVF cycles are successful and others are not. There is still no strong evidence BPA has any effect on human fertility, and while women shouldn’t avoid soy while undergoing fertility treatments, they should not feel they must eat soy to “counteract” any possible effects from BPA.