Is soy good or bad for men?
In addition to protein, fiber, vitamins and minerals, and omega-3 fatty acids, the soybean is rich in phytoestrogens (“plant estrogens”), a subclass of antioxidants called “isoflavones.”
Chemically, phytoestrogens are structurally similar to the human sex hormone estrogen, interacting with the hormones in mammals with estrogen receptors. That’s where the controversy begins.
According to Holly Wilson, M.D., the confusion stems from misunderstanding the difference between the naturally occurring phytoestrogens in plants and the human steroid hormone, estrogen, that regulates sexual function. She says:
Phytoestrogens ... functionally are weakly estrogenic (weakly mimicking estrogen) or antiestrogenic (blocking estrogen’s effects). The metabolism and functionality of phytoestrogens are incredibly complex, and vary between individuals.
Despite scientific studies to the contrary, the same doubts and fears about soy prevail, as consumers ask:
Does soy feminize men?
The myth that men develop breasts from soy sprang from thinking phytoestrogen and human estrogen are synonymous. Wilson calls it an “urban legend,” adding that if the two compounds were the same “there would be a lot of men in need of bras!” A study by Martinez and Lewi, however, reported a 60-year-old man who drank 6 quarts of soy milk a day for 6 months developed gynecomastia. But, the symptoms subsided when he stopped the soy. Furthermore, a study by Mark Messina, PhD, found the soybean isoflavone has no feminizing effect on men.
Does soy cause sexual dysfunction?
Surprisingly, a Google search reveals more fears and warnings on this topic than the others, with sensational headlines like: “Shocking Effects of Soy,” “Soy Dangers!” “Sexual Side Effects!” Sexual problems have often been blamed on soy’s phytoestrogens. However, studies, including Messina’s cited above, find soy has no effect on testosterone levels and doesn’t cause erectile dysfunction.
How about infertility?
A study by Glover and Assinder on rodents given a diet high in phytoestrogens showed those amounts temporarily reduced fertility. But that’s rodents. A meta-analysis in Fertility and Sterility showed no effect of soy isoflavones on the reproductive hormones in men, and a study in Clinical Science revealed isoflavone supplementation has no effect on sperm concentration, count, or motility.
Higher risk for cancer?
Because human estrogen promotes the proliferation of cells, at high levels this can increase the risk for some cancers. Phytoestrogens aren’t estrogen, though, and actually have been found to reduce cancer risk, including prostate cancer. A meta-analysis by Lin Yan and Edward L. Spitznagel associated soy with a reduction in prostate cancer risk in men.
So, why do these myths persist? Wilson warns about the ongoing anti-soy campaigns of Weston A. Price Foundation that lobbies for animal farming and discredits veganism, especially through its “Soy Alert” releases.
It seems any negative effects from soy resulted from overindulging (6 quarts of soy milk a day?) and are reversible. Then, doesn’t it make sense to balance, rather than eliminate, this nutrient-dense food in a man’s diet?
Read more about The Soybean Saga: Myths and Facts.
Note: We use soy in some of our plant-based recipes as a rich, gluten-free source of protein and micronutrients. Veestro ingredients are posted online so you can explore what’s right for you.
Sources:Darya Pino, Does Soy “Feminize” Men? Fact vs. Myth, Zocdoc
Holly Wilson, M.D., A Vegan Doctor Addresses Soy Myths and Misinformation, Free from Harm