When the customer in front of you at Starbucks orders a triple soymilk latte, you know it's time to start paying attention. Soy is the latest good-for-you-food craze. Before you go on a tofu binge, read on to find out what the experts do and don't know about the benefits of soy.

Why Soy?

Soy foods are an excellent source of isoflavones, which are phytoestrogens or weak estrogen-like substances made from plants. These plant compounds, known broadly as phytochemicals, are under intense scrutiny these days as scientists try to understand their nutritional value and their possible disease-fighting role.

Soy and Cholesterol

Everyone agrees that soy protein can help reduce levels of "bad" low density lipoprotein (LDL) cholesterol in humans.

The Food and Drug Administration has given the green light to food companies to make health claims about the role of soy protein in reducing cholesterol and the risk of heart disease. To earn the claim, a food must contain at least 6.25 grams of soy protein per serving. It also must meet the requirements for low fat, low saturated fat and low cholesterol content.

Studies show that 25 grams of soy protein daily in the diet is needed to produce a significant cholesterol lowering effect.

Soy and Cancer

The picture is less clear when it comes to soy and cancer prevention. The American Institute for Cancer Research, one of FoodFit's Resource Associations, issued a statement last fall urging consumers to be cautious because many key questions remain (see the AICR's newsletter).

"The data on soy and prostate cancer, for instance, are very encouraging but limited. The data on soy and breast cancer are more mixed, especially for women who have or have had breast cancer," soy expert Mark Messina said in the AICR statement.

"It's simply not possible yet to draw any conclusions about soy consumption and cancer prevention, but further research is certainly warranted," he said.