Soy is often thought to be a healthy alternative to other foods. However, certain chemicals contained in the soy plant can impact male fertility. Instead, a small portion of the testosterone that a man produces is converted into estradiol the male equivalent of testosterone by the enzyme aromatase. Ideally, this process helps maintain your hormonal balance- it allows for just enough estrogen for your body to keep your brain running and your bones strong, but not enough to interfere with your testosterone levels. When you consume outside estrogen, this delicate balance is thrown off, leading your body to have too much estrogen and too little testosterone. A healthy level of testosterone is crucial to the production of sperm.
Soy Linked to Low Sperm Count
Diet and male fertility: Foods that affect sperm count - UChicago Medicine
The soybean originated in East Asia over 10, years ago. Soybeans are cultivated to create a range of popular products, from soya milk and tofu to fermented products, such as miso and tempeh. Soya-based foods are no longer just a pillar of the East Asian diet but are now vegetarian staples in supermarkets worldwide. However, there is a lingering concern that soy foods can affect the fertility of both men and women.
How does soy impact male fertility?
Dietary intake of phytoestrogens has been related to abnormal semen quality and hormone levels. However, its effect on couple fecundity is still unclear. Intake of soy products was assessed in men from couples undergoing infertility treatment with in vitro fertilization IVF. Couples were recruited between February and May and prospectively followed to document treatment outcomes including fertilization, implantation, clinical pregnancy and live birth.
The reason for this relationship between soy and sperm count isn't clear. However, researchers speculate that soy increases estrogen activity, which may have a negative affect on sperm production and also interfere with other hormonal signals. Jorge Chavarro, a research fellow in the department of nutrition at the Harvard School of Public Health. Research in animals has shown that isoflavones and estrogen can have a potentially negative affect on reproduction, including decreased fertility, Chavarro said.