One ingredient you'll find cropping up in all sorts of functional foods is soy. Why? According to the FDA, "25 grams of soy protein a day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease." This claim—along with soy's purported help in reducing menopausal symptoms—has unleashed a shopping cart full of soyfoods for women, including Quaker Oatmeal Nutrition for Women (oatmeal with soy protein), as well as French Meadow Bakery's Woman's Bread with Soy Isoflavones. And, c'mon, who hasn't sampled a Luna bar (with soy protein for heart health)?

The FDA permits food makers to use its heart-health claim if a product supplies 7 grams of soy per serving, figuring you can include soy products in four meals a day to get the recommended amount.

Current research shows that soy lowers cholesterol levels by 5 percent—and may also help reduce menopausal symptoms. Take note, however: The evidence of soy's benefits is inconclusive, with marketing ahead of science in the area of women's health. For instance, the best evidence currently available on soy's health effects suggests that it lowers cholesterol. "It's a small lowering, 5 percent, but over a lifetime it can have a big impact on heart disease," says Mindy Kurzer, PhD, a University of Minnesota professor and soy researcher. "It appears soy isoflavones also improve some other aspects of heart disease, such as elasticity of blood vessels, which would possibly deter the development of high blood pressure and plaque formation. The next strongest area is menopausal-symptom reduction. Areas with less agreement involve bone metabolism and osteoporosis." And soy's role in helping prevent breast cancer is still controversial. If the FDA deems soy isoflavones worthy of an official health claim for preventing menopausal symptoms, expect to see a whole new host of soyfoods geared toward the 45-plus set.

—T.R.