Soy - A Natural Disease Fighter?

Reviewed by James Brann, M.D.

In 1998 Food & Drug Administration recently approved soy as a food for lowering cholesterol and preventing coronary heart disease. While there is a large body of evidence supporting soy as a natural health food, there is some research that raises questions about soy's efficacy. How do you really know whether soy is good for you? It is important you make your own decisions about your health. Below you'll find some of the main information available today about soy so you can decide whether this wonder food deserves a place on your plat.

Soy and Disease
Multiple studies suggest the isoflavones present in soy, including genistein and daidzen can help reduce a person's risk of developing cancer. Soy may also prevent the growth of breast cancer tumors. Many studies link soy with a decrease in hot flashes.

Many of the studies examining soy have compared the Asian population with that in the U.S., since historically soy is much more of a dietary staple in Asian diets than in U.S. diets. Soy does contain phytoestrogens, which are plant-based estrogens that may have some of the effects of natural estrogen in the body, including regulating a woman's hormones.

Still other studies suggest that soy is helpful but only if consumed early in life. The benefits of eating soy aren't associated as much with the older population. Many of the studies conducted on soy products involve animal subject, thus it is hard to determine whether the effects are equally relevant to the human population.

The American Heart Association suggests that consuming 25-50 grams of soy every day may help lower your bodies LDL cholesterol level. This is largely due to isoflavones present in soy products. A study conducted by University of Illinois at Champaign Urbana researchers suggests that menopausal women who eat large amounts of soy every day have stronger and less brittle bones than those who do not. Still other studies including those done by the Mayo Health Clinic note that consumption of soy may help reduce our risk of cancer, stroke, hot flashes and even improve the symptoms of osteoporosis.

However, it is important that you know most researchers also recognise the controversy surrounding soy and soy products. Soy isn't necessarily a cure for any disease. Rather, it may help people enjoy some modest health benefits.

Not All Soy Is Alike
Not all soy products are equally valuable. Generally the research supports use of fermented soy products. Fermented soy is the kind of soy most often consumed in Asian diets. Fermented soy products include:
  • Miso soup

  • Natto

  • Tempeh

  • Soy sauces

  • Fermented soymilk

  • Fermented tofu
Most studies support the use of fermented tofu for preventing or reducing your risk for certain diseases. However there are also tons of genetically modified and non-fermented soy products on the market. Nonfermented soy products contain an ingredient called phytic acid. This substance can inhibit your body's ability to bind with certain nutrients, thus this form of soy may not be as valuable as fermented soy products. Non-fermented forms of soy include some soy milks, tofu and processed soy found in baby formula and meat substitutes.

It is important you also realize that some studies suggest non fermented or genetically modified soy products may actually be bad for you. One study for example linked high consumption of tofu in midlife with a more than double increased risk for developing Alzheimer's disease. Still other studies suggest the phytoestrogens in soy may increase a woman's risk of giving birth to a baby with birth defects, and others suggest that soy formula may have some negative influences on children.

One thing is certain... experts are still hotly debating soy as a disease fighting nutrient. If you feel you stand to benefit from incorporating soy in your diet, be sure you use fermented soy products when possible, since most studies suggest this is the most helpful form of soy. You can also talk with your doctor about your concerns and questions. While soy may be helpful for some, it may result in gastrointestinal distress and general discomfort for others. At this point the jury is still out, even though there is a large body of evidence that generally supports use of some soy products in the diet. The key may be incorporating a modest amount of soy, rather than using soy as a dietary staple, in your diet.