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Much of the worry and the wonder about soy centers around its isoflavone phytoestrogens—the naturally occurring, estrogen-like compounds found in the bean. Anecdotes about men developing gynecomastia (breast enlargement) or young girls experiencing early-onset puberty as a result of consuming soy foods are largely just that—anecdotal; the scientific literature offers little, if any, support for such claims. "Phytoestrogens are chemically somewhat similar to estrogen," says Weaver, "but their ability to bind with estrogen receptors is much weaker. So their effect, and therefore their risk too, is a lot less." Weaver adds that Asian populations have eaten whole soy foods for centuries, "and Asians don't have an earlier onset of menarche than Caucasians. In the US you can get supplements that are purified soy isoflavones, and you might be able to take enough to manipulate your reproductive cycles some, but Americans mostly don't eat enough soy to worry about it."
Bottom line: Consumed in moderation by people with no soy allergies, soy foods are safe to eat. Still concerned? Stick with whole-bean forms such as tofu, miso, and edamame, and avoid processed foods made with high concentrations of soy protein isolates.
Being cold causes a cold.
You'd think this one would fall firmly in the camp of folklore, right? Well, think again. A 2005 study conducted at the Common Cold Centre in England found that a drop in body temperature could in fact precipitate a cold. Of the study's 180 participants, half were asked to keep their feet in icy water for long periods, while the other 90 control group participants kept their feet in empty basins. Within five days, 29 percent of those in the ice-water group developed sore throats and runny noses, while only 9 percent of the dry group came down with cold symptoms. The study's authors theorize that cold weather conditions can lower immunity and constrict blood vessels in the nose, allowing a mild, dormant virus to blossom into a full-blown cold.
Bottom line: Zip up your coat. Isn't it nice to know your mother was right about this one?