Eating soyfoods can be easy and satisfying, and may even reduce your risk of cancer. Soyfods are rich in a group of compounds called phytochemicals, which are thought to have beneficial effects. One group, called isoflavones, is especially important because they may fight cancer in a variety of ways. Isoflavones are found in significant amounts only in sotbeans and in soyfoods, such as tofu, soy milk, tempeh and textured soy protein.

Cancer is Not Inevitable

Cancer is our nation's number two killer - right behind heart disease. Cancer takes the lives of a half-million people every year, but, in many cases, it can be prevented. Lifestyle changes can greatly reduce cancer risk. Diet is one factor that has a significant impact on cancer. According to the National Cancer Institute, one-third of all cancer deaths are linked to diet and all the most common western cancers have some relationship to diet.

Dietary guidelines for reducing cancer risk include the following:

• Decrease fat intake
• Increase fiber intake
• Increase fruit and vegetable intake
• In addition, many studies show that eating soyfoods may help protect against cancer.

Soyfoods & Cancer: The Evidence

People who live in countries where soyfoods are a common part of the diet are less likely to develop certain cancers. For example, breast cancer mortality rates are much lower in Asia, where soyfoods like tofu and soy milk are frequently consumed. In the U.S., where these foods are seldom used, women are four times more likely to die of breast cancer than Japanese women.

Of course, there are many differences between the lifestyles and diets of American and Japanese women. Any of them might contribute to these differences in breats cancer rates. However, many studies have found that people in Japan who eat soyfoods daily are less likely to get cancer than people in Japan who seldom eat soyfoods. In these cases, other diet and lifestyle factors are similar in the two groups. In other words, the main difference between these groups lies in how often they eat soyfoods.

As little as one serving of soyfoods each day seems to protect against many types of cancer including lung, colon, rectal, stomach, prostate and breast cancer. A serving is equal to 1/2 cup sooked soybeans, tofu, textured vegetable protein or tempeh, or 1 cup soy milk.

Laboratory studies also support a cancer-protective role for soy. When animals are fed diets containing soy and then given a substance that causes cancer, they develop fewer tumors than animals who don't have soy intheir diets.

How Soybeans Work

Scientists have identified several potential anti-cancer substances in soybeans. Although all of these might contribute to the possible anti-cancer effects of soy, the isoflavones stand out. One isoflavone, called genistein, has especially caught the attnetion of scientists. When genistein is added to many different types of cancer cells growing in laboratory test tubes, the growth of these cells stops. More than 100 studies have demostrated the effectiveness of genistein.

Genistein is thought to act against cancer in several ways. Genistein may actually work in ways similar to some of the common drugs used by physicians to treat cancer. Scientists believe that certain enzymes in the body convert normal cells to cancer cells. Often, cancer drugs work by inhibiting these enzymes. In cancer cells, genistein has been shown to work in a similar fashion; it interferes with the activity of these enzymes.

Genistein may act against many cancers that are "hormone-dependent" such as breast and prostate cancer. These cancers depend on hormones for their growth. Genistein may interfere with these hormones and thus stop cancer cells from developing and tumors from growing.

There may even be a role for genistein in treating cancer. Some research indicates that genistein can interfere with the process by which tumors receive nutrients and oxygen, which are needed for tumor growth. Researchers at the University of Minnesota recently attached genistein to antibodies and injected them into mice with leukemia. All these mice survived, whereas a group of mice that didn't get genistein died within three months.

A Cancer Protective Diet

There is no such thing as a miracle food that will automatically protect you from cancer. The only effective approach is to adopt an overall lifestyle that is best able to reduce risk of cancer. This means avioding tobacco, using sunscreens and reducing alcohol intake. A healthful diet is also very important. Build your diet around fiber-rich foods such as whole grains, beans, fruits and vegetables. There is reason to believe that adding soyfoods to your diet can help, too. As little as one serving a day might be enough to help protece against cancer. Here are some easy 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 vegetable protein (TVP); just add water and taco seasoning to the TVP.
• Add fresh green soybeans to salads.
• Add cooked, dried soybeans to chili recipes.
• Try plain, non-flavored 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 dip.

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