Recently the FDA ruled that manufacturers of soy protein products can claim on their product labels that 25 grams per day of soy protein, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease.

The FDA's ruling is based on studies that have shown that adding soy to your diet can lower your cholesterol. The FDA reviewed about 40 studies that were published between 1976 and 1999. In one study, a research team analyzed the results of 38 clinical trials on soy's effects on cholesterol levels in both men and women. Overall, decreases in the total cholesterol levels of the participants were observed in 34 out of the 38 studies. On average, the participants had consumed 46 grams of soy protein each day. In another trial, 20 grams per day of soy protein reduced cholesterol levels in women nearing menopause.

If you look on the shelves of your health food store or supermarket in search of soy protein products, you'll see everything from veggie burgers to food bars to powdered soy protein beverages. However, not all soy protein products contain the same amount of protein. Whole soybeans have approximately 38 percent. Based on the manufacturing processes used, the products derived from soybeans differ significantly. For example, soy protein isolate (added to many soy food products, such as sausage soy patties or soybean burgers) has about 92 percent protein; soy flour has about 50 percent. Tofu, however, has only about 16 percent protein (unless, of course, soy protein isolate has been added to it).

The best way to find out about protein content is to look on the product's Nutrition Facts label to see what the percentage of soy protein is. Also look at the list of ingredients: if a product contains isolated soy protein (or soy protein isolate), the protein content should be fairly high. The new FDA-approved health claim, appearing more and more on soy products, will also indicate how many grams of soy protein are in one serving of that product.

Note: There's a difference between soy supplements (commonly sold in tablets or capsules) and soy protein products. Soy supplements are generally composed of concentrated soy isoflavones. While soy isoflavones may be helpful in treating symptoms of menopause (isoflavones behave similarly to estrogen), there is not enough evidence to support using soy isoflavones to keep cholesterol levels down.

The bottom line: to enjoy the cholesterol-lowering benefits of soy, consider adding more soy protein food products to your diet.

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