Sources of Isoflavones

Isoflavones are naturally occurring compounds found in plants that have similar effects on the body as estrogen. Many people, particularly older women who do not wish to undergo traditional hormone replacement therapies, choose to consume isoflavones to gain their potential health benefits. For those who wish to add isoflavones to their diet, both natural and synthetic sources of the compounds are available.

Soy

• While grains, legumes and certain vegetables provide small amounts of isoflavones, but soybeans provide a more concentrated amount of isoflavones than any other food. Products made from soybeans include tempeh, natto, miso and tofu. Soybeans picked and eaten in their natural green state are called edamame. Other sources of soy include soy milk, soy yogurt, soy cheese and soy-based meat substitutes.

Red Clover

• Among the numerous natural sources of isoflavones, the red clover, a perennial plant with white to red flowers, is one of the most important sources. The red clover is a member of the legume family. It is used throughout the world as a source of hay for horses, cattle and sheep. For humans, the leaves and young sprouts of the plant are used as a source of protein. Isoflavones derived from the red clover reduce the symptoms of menopause as well as help maintain bone density in both peri-menopausal and menopausal women. Red clover isoflavones do not, however, have a cholesterol reducing effect like soy isoflavones.

Supplements

• You can purchase Isoflavone supplements and extracts in the United States without a prescription. These supplements are not standardized, so the amount of isoflavones contained in them varies considerably from product to product. Quality control of these products may also be an issue. An independent test of isoflavone supplements available in the United States showed that approximately 50 percent of the products tested contained isoflavone content that differed by greater than 10 percent than the amount shown on the label. Although most supplements contain isoflavones extracted from red clover or soy beans, some contain a synthetic form of isoflavones called ipriflavone. Ipriflavone is a chemical substance designed to have the bone-stimulating effect of naturally occurring isoflavones, but not their estrogen-like effects. Consequently, ipriflavone is not helpful in relieving the symptoms of menopause.

Infant Formulas

• Many infant formula manufacturers offer soy-based formulas that contain significant amounts of isoflavones. Although the benefits of soy-based formulas are unclear, these products offer a viable alternative for infants who are allergic to cow's milk.