Eating soyfoods can not make someone less masculine, lead to man-boobs, cause early puberty or decrease fertility. A recent literature review confirms that soyfoods do not have any feminizing effects on men or boys (2010, Fertility and Sterility). In reality, a diet that includes soyfoods can help support healthy growth and development for young boys, and soyfoods are a great option for men looking to maintain healthy weight and cholesterol levels. Research is also finding that for athletic men, soy protein helps muscles recover better after workouts (2007, Current Medicinal Chemistry).
Soybeans contain natural, bioactive components called isoflavones, or phytoestrogens. Isoflavones are actually found in lots of plant foods like apples, carrots and other beans. While the chemical structure of an isoflavone is similar to that of estrogen, the two function differently in the body.
Soy isoflavones do not act the same as estrogen does in the human body. A significant review of over 30 soy studies disproved any link between soy and an effect on testosterone levels in men (2009, Fertility and Sterility).Consuming a well balanced diet that includes soyfoods does not increase estrogen levels in men or boys.
Stacey Krawczyk, MS, RD, LDN, with the National Soybean Research Laboratory and mother of two young boys comments that, “as a research dietitian with an expertise in family nutrition, I take meal planning very seriously and I do not worry at all when I provide soyfoods to my two growing boys—they love the taste of soyfoods, and I love the healthy nutrition they offer, especially when I need to rely on quick and easy meals to meet our busy schedules.”
Check back for other Soy Myths in our Mysteries of Soy Series! What myths and Truths do you know about soy?