Eat Your Soy, Boy
Tuesday, May 4, 2004
Yes, it's true that your wife, girlfriend or significant other has been eating a lot of soy lately, mainly to boost her female hormones. That doesn't mean it's bad for you, fella. Instead of pushing aside that soy milk, go ahead and pour some on your morning cereal. Dig into the soy burgers at the office cafeteria and the tofu that appears in your takeout stir-fry.
It turns out that soy, at least in the doses most people will consume it in food, may be good for guys, too. A growing number of studies suggest that soy has plenty of health benefits for men -- from lowering cholesterol levels to protecting against prostate cancer -- and few downsides.
"Real men should eat soy," said Kenneth Setchell, professor of pediatrics at the Cincinnati Children's Medical Center, who has studied soy for 30 years. "Generally, men are put off by soy. It tends to be sort of a woman's thing. That's a great pity, because the evidence that soy protects against prostate cancer is quite strong."
While there have been worries that men who consume large quantities of low-carb soy bread, soy cereal or other soy-filled foods may get a little too in touch with their feminine sides, research findings have generally not borne out those fears.
"Soy is a very healthy food," said physician James Anderson, who has studied soy for 15 years at the University of Kentucky in Lexington and is convinced enough of its benefits to eat about a dozen servings of soy per week. "It's very safe."
Most concerns about soy have centered around the fact that it is a rich source of isoflavones, substances that mimic the effects of the female hormone estrogen. To determine what these plant-based chemicals might do, Steven Zeisel and his colleagues at the University of North Carolina at Chapel Hill fed megadoses of soy to men as part of a recent National Cancer Institute study.
Nipple discharge, breast enlargement and slight decreases in testosterone occurred with the megadoses. But "we still couldn't find anything that was serious, and we went up to doses that are probably 30 times what you could get from normal foods," Zeisel said. "I don't think that there are a lot of estrogenic worries. Your testicles will not shrink and you won't have massive breast enlargement" from eating soy.
And if you stick with foods rich in soy as opposed to supplements, researchers say, there's no evidence of harm, unless you happen to be among the one in every 1,000 people who are allergic to soy. "It's quite difficult to overconsume soy, to be honest," said Setchell.
Not only is soy a rich source of high-quality protein, but it also contains complex carbohydrates that don't raise blood sugar as high as more processed carbohydrates. It has fiber, folic acid (a key B vitamin), healthy fat and antioxidants that help protect against cancer.
There's also evidence that soy acts as a probiotic in some people, promoting growth of healthy bacteria in the gastrointestinal tract that in turn produce health-promoting substances. While it's possible these days to eat soy at every meal and snack, it only takes a small amount of soy to produce health benefits. Less than a handful of soy nuts, about a fifth of a cup, provides 12 grams of protein, said Anderson, who keeps a stash near his desk for snacks. "If you can eat a third of a cup a day, that would give good protective levels in terms of heart disease."
Will such soy-filled products as low-carb bread, soy cereal, soy crackers and cookies have the same benefits as traditional soy sources?
"My feeling is that soy milk and tofu have the best test of time," said David Jenkins, professor and chairman of nutrition and metabolism at the University of Toronto and St. Michael's Hospital in Toronto. The soy isolates found in meatless burgers and hot dogs "have also been shown to be very effective," Jenkins said. By contrast, soy sauce has only minimal levels of active soy ingredients and comes with massive amounts of sodium.