Eating soy may protect against cancer and build bones, but many have misconceptions about it
April being soyfood month means it’s time to dispel soy myths and review the benefits of soy to encourage more people to try this tasty and economical legume.
Soy is a wonderful source of plant protein that differs from other plant proteins in that it contains all nine essential amino acids as well as calcium, iron, zinc, phosphorous, magnesium and fiber. Soy contains isoflavones, which are beneficial, but have contributed to misinformation.
Isoflavones are a plant hormone that resembles human estrogen but is much weaker, with an effectiveness of 1/1,000 of estrogen. Isoflavones may protect against certain types of cancer and have a role in bone health. A gram of soy protein has 3 mg of Isoflavones. The average Asian diet has 25-50 mg of isoflavones from food and the average American diet has less than 3 mg a day.
Two persistent soy myths concern the effect of soy on men’s health and breast cancer in women. The weight of scientific evidence shows that soy intake has no effect on erectile function, sperm motility or quality or testosterone levels.
Regarding breast cancer, a 2009 study by Shu et al in JAMA demonstrated a deceased risk of death and recurrence of breast cancer in women with the highest soyfood intake. The only soy product to use sparingly would be soy sauce. One tablespoon has 40% ( 920mg) of daily recommended sodium. Of course, adding that same tablespoon to a dish to bring out the umami would be fine if you were serving four people.
It is easy to add good taste and great nutrition with a bit of soy. Use soynut butter and bananas on whole wheat toast; add roasted soy nuts to a trail mix and sauté tofu in your next stir fry.
The easiest work snack and one of my favorites is edamame. Frozen edamame are in the supermarket freezer case. A half cup serving is 65 calories, 6 grams of protein (18 mg of isoflavones) and 3 grams of fiber. For more on soy including recipes go to www.soyconnection.com
Sheah Rarback MS, RDN is a registered dietitian nutritionist in private practice in Miami.