Introduction

This fact sheet provides basic information about soy-uses, potential side effects, and resources for more information. Soy, a plant in the pea family, has been common in Asian diets for thousands of years. It is found in modern American diets as a food or food additive. Soybeans, the high-protein seeds of the soy plant, contain isoflavones-compounds similar to the female hormone estrogen. This fact sheet highlights what is known about soy when used by adults for health purposes.

Common Names-soy

Latin Names-Glycine max

What It Is Used For

People use soy products to prevent or treat a variety of health conditions, including high cholesterol levels, menopausal symptoms such as hot flashes, osteoporosis (a condition in which bones become thin and brittle), memory problems, high blood pressure, breast cancer, and prostate cancer.

How It Is Used

• Soy is available in dietary supplements, in forms such as tablets and capsules. Soy supplements may contain isoflavones or soy protein or both.
• Soybeans can be cooked and eaten or used to make tofu, soy milk, and other foods. Also, soy is sometimes used as an additive in various processed foods, including baked goods, cheese, and pasta.

What the Science Says

• Research suggests that daily intake of soy protein may slightly lower levels of LDL ("bad") cholesterol.
• Some studies suggest that soy isoflavone supplements may reduce hot flashes in women after menopause. However, the results have been inconsistent.
• There is not enough scientific evidence to determine whether soy supplements are effective for any other health uses.
• NCCAM is supporting ongoing studies of soy, including its effects on women's arteries and bones after menopause.