Eating soyfoods may help reduce the risk of heart disease, the leading cause of death in the United States. Soyfoods are not only low in saturated fat and free of cholesterol, the protein in soyfoods has been shown to directly lower blood cholesterol. Also, soyfoods are rich in a group of compounds called isoflavones, which may work in several ways to fight heart disease. Isoflavones are found in significant amounts only in soybeans and soyfoods, such as tofu, soy milk, tempeh and textured soy protein.

Heart Disease is Not Inevitable

Heart disease is the leading cause of death in the United States and kills more than 100 people each hour in this country. But there is a wide variation in heart disease rates throughout the world. Different lifestyle, including diet, is the main reason.

It is important to eat less saturated fat and cholesterol in order to reduce the risk of heart disease. Maintaining ideal weight and exercising also help. But many other factors can affect heart disease. For example, soybeans and foods made from soyeans may play a role in keeping the heart healthy.

Soyfoods Are Low in Saturated Fat and Free of Cholesterol

High blood cholesterol levels increase the risk for atherolsclerosis, which is the underlying cause of heart disease and heart attacks. Approximately 40 million Americans have blood cholesterol levels that are too high. Both saturated fat and dietary cholesterol increase blood cholesterol levels.

Many foods that are rich in protein are too high in saturated fat and cholesterol. Soyfoods are different because they are high in protein but low in saturated fat and conpletely free of cholesterol. The fat in soyfoods is mostly polyunsaturated fat - which doesn't raise blood cholesterol levels. One serving of cooked soybeans (1/2 cup) provides 14 grams of high-quality protein, but only about one gram of saturated fat and no cholesterol. So replacing some animal protein in the diet with soyfoods will help lower blood cholesterol levels and reduce the risk of heart disease.

Soy Protein Directly Lowers Blood Cholesterol Levels

Almost 30 years ago, researchers showed that protein from soyfoods could lower blood cholesterol. Since then, more than 40 studies involving human subjects have also shown this. Soy protein decreases blood cholesterol levels by about 10 to 15 percent in people with elevated cholesterol. Even in people who have already reduced their blood cholesterol by eating a low-fat diet, eating soy produces futher drops in cholesterol. A 10 precent decrease in cholesterol reduces the chance of having a heart attack by 20 to 30 percent.

How Much Soy Protein is Needed?

About 25 grams of soy protein per day may be enough to lower cholesterol. This is the amount of soy protein found in just 1 cup of soybeans. Higher amounts of soy protein (25 to 50 grams) are likely to produce even bigger decreases. Soy protein appears to be effective whether you use it in place of other protein foods in your diet or if you simply add it to your existing diet. The National Health Service in Italy provides soy free of charge to physicians for the treatment of high blood cholesterol.

Soy May Prevent Heart Disease in Several Ways

Reducing blood cholesterol levels is very important for preventing heart disease. But many other factors affect heart disease risk, too.

Soy protein inhibits cholesterol oxidation. Only oxidized cholesterol - that is, cholesterol that has undergone structural changes because of exposure to oxygen - can damage the arteries.

In test tubes, a compound in soybeans called genistein inhibits the growth of cells that form the plaque that lines the arteries.

Genistein may inhibit the formation of blood clots. Although these effects of soy are speculative, they indicate that eating more soyfoods is a smart move that may help portect the health of your heart.

A Healthy Diet Can Reduce Your Risk of Heart Disease

There is no such thing as a miracle food that will automatically protect you from heart disease. The only effective approach is to adopt an overall lifestyle that reduces the risk of heart disease. Exercise regularly and avoid tobacco. Reduce intake of fat (especially of saturated fat) and cholesterol. Build menus around fiber-rich foods such as whole grains, beans, fruits and vegetables. Adding soyfoods to meals can help too. Here are some ways to add soyfoods to your diet:

• Try a breakfast milkshake made with soy milk, bananas and other favorite fruits.
• Try a taco made with textured soy protein (TSP); just add water to the TSP and season with a packet of taco seasoning.
• Add fresh green soybeans to salads.
• Add cooked, dried soybeans to chili recipes.
• Try plain, unflavored soy milk in mixes for cakes, muffins or pancakes.
• Replace part of the flour in cake and cookie recipes with soy flour.
• Stir-fry chunks of tofu with fresh vegetables and serve over rice.
• Puree soft tofu and flavor with onion soup mix for a dip.

This information was prepared by Mark Messina, PhD, and Virginia Messina, MPH, RD, authors of The Simple Soybean and Your Health