In the first study of its kind, researchers from Harvard University found that soy food intake may decrease the deleterious effects of BPA on success rates of patients undergoing in vitro fertilization (IVF). BPA (bisphenol A) is a chemical found in many common consumer products such as plastic bottles and the lining of canned food that acts like endocrine disruptor in the body. Over 7 million tons of BPA was produced last year alone and women with higher levels of BPA in their system have been found to have more difficulty conceiving and higher rates of miscarriage.
In this study published in the Journal of Clinical Endocrinology and Metabolism, 239 women underwent 347 IVF cycles over 5 years. The BPA levels in their urine were monitored before and after treatment and their soy intake was reported along with many other lifestyle factors through their treatment. The researchers found lower live birth rates in women with higher levels of BPA and a dose response association showing as the levels of BPA increased the live birth rates decreased. This trend was not found in women who ate soy food products throughout their treatment despite similar levels of BPA in their urine. Previous studies in animal models have also shown a protective effect of soy intake in rodents exposed to BPA but this is the first research to show this trend in humans.
Soy products have often been viewed as harmful to overall health given their own estrogenic effects in the body, however a previous study published in 2015 showed soy intake was associated with higher live birth rates in patients undergoing IVF treatment. In this study, also out of Harvard, 315 women underwent 520 IVF cycles over 6 years and their soy intake was reported by questionnaire. Live birth rates were approximately 10% higher in the group who ate some soy products compared to women who ate no soy products during their IVF cycle. The authors reported on the association but concluded that they could not explain why soy may have a positive impact on success with IVF. The protective effect of soy against the endocrine disrupting effects of BPA may be the answer.
Before IVF patients run to the grocery store for tofu, the authors conclude that these results should be studied further. The key to this study is the finding that a lifestyle choice such as diet may impact success with IVF and that Western medicine and technology can only do so much. Studies like this should empower patients and providers to ask more questions about what they can do at home through diet, exercise, overall well-being to improve their chances of success with all fertility treatments.
1. Chavarro JE, et al. Soy Intake Modifies the Relation Between Urinary Bisphenol A Concentrations and Pregnancy Outcomes Amoung Women Undergoing Assisted Reproduction. J Clin Endocrinol Metab March 2016 101(3):1082-1090.
2. Muhlhauser A, Susiarjo M, Rubio C, et al. Bisphenol A effects on the growing mouse oocyte are influenced by diet. Biol Reprod. 2009; 80:1066 –1071.
3. Dolinoy DC, Huang D, Jirtle RL. Maternal nutrient supplementa- tion counteracts bisphenol A-induced DNA hypomethylation in early development. Proc Natl Acad Sci USA. 2007;104:13056– 13061.
4. Vanegas JC et al. Soy intake and treatment outcomes of women undergoing assisted reproductive technology. Fertil Steril 2015; 103(3): 749-55.
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