BEFORE YOU REACH for the power bar or sports drink powder, maybe you should take a moment and see what’s really in there. One of the main ingredients in your energy boost might actually be harming you. The culprit has always seemed so innocuous: soy. Once touted by the Federal Drug Administration as a wonder food, soy has increasingly become a staple filler for many health products and snacks. From dried edamame to fake meat—even that tasty glass of soymilk—most people are getting more from this little bean then they need. Especially men.
Soy contains phytoestrogens, or plant estrogens, known as isoflavones. The isoflavones act like human estrogen in the body and are known to lower men’s testosterone levels. While its chemicals don’t affect every man that eats soy, numerous cases have showed the plant’s harmful effect. Dr. Kaayla Daniel, author of The Whole Soy Story: The Dark Side of America’s Favorite Health Food, said the way our bodies absorb the phytoestrogens differs from person to person. The main thing, she mentioned, is to moderate your consumption of the product.
“Many people are consuming excessive amounts of soy,” she said. “A couple cups of soy milk is a high amount of soy. For people not allergic to soy, having a small quantity a couple times a week is OK.” A safe amount of soy, Daniel suggested, consists of miso soup, soy milk in coffee or tea or small chunks of tofu in a stir fry two or three times a week. Or else, you could get gynecomastia, otherwise known as man-boobs. OK, you probably won’t need a bra, since gynecomastia usually occurs in adolescent boys, but an excessive intake of soy can lower your libido and sperm count.
One 2007 study by the Harvard School of Public Health concluded that the higher intake of soy-based foods corresponded with lower sperm concentration in its subjects. The study was based on 100 men who were having trouble getting their partners pregnant. Once their semen was looked at, the data showed that the men who ingested lots of soy had 41 million sperm per milliliter less then their soy-free counterparts.
“There is pretty good evidence both from the science point of view and the social history about soy effecting hormones by the estrogenization of men,” said Daniel, citing examples in Japanese tales where wives gave straying husbands soy to lower their libido and how monks started eating it because it helped them remain celibate by curbing their desires.
“It’s really a quantity and quality issue,” said Daniel. “The problem is when people start seeing soy as a health food, and when you start using it as a meat and dairy replacement.”
All the studies about men and soy came from men who are constant consumers of the product. Little bits of soy here and there do not create these results, according to experts. Also, what soy does to your body depends on you. Weight, diet and lifestyle can also affect the male body this way. In general, unless you are prepubescent, man-boobs only happen in extreme cases.