Common Name: Soy
Latin Name: Glycine max


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. The following information highlights what is known about soy when used by adults for health purposes.

What Is Soy 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, memory problems, high blood pressure, breast cancer, and prostate cancer.

How Soy Is Used?

The medicinal parts are the soya lecithin extracted from the soya bean, the soya oil and the soya seed.

Soy is approved by Commission E for raised levels of cholesterol.

Folk medicine: Soybean is used for less severe forms of hypercholesterolemia when dietary measures are required. Soybean is also used for liver and gallbladder complaints, anemia, poor concentration, cerebral and nerve conditions, and general debility.

Chinese Medicine: Soybean is used for hyperhidrosis, night sweats, confusion and joint pain.

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 Skeptics Say

  • 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.

Soy Protein for Cholesterol

Like fiber and whole grains, soy protein also boasts an FDA-approved heart health claim. Reynolds et al conducted a meta-analysis examining the effect of soy protein supplementation on serum lipid levels in adults. Soy protein supplementation was associated with a signiicant reduction in mean serum total cholesterol, LDL cholesterol, and triglycerides, and a signiicant increase in high-density lipoprotein (HDL) cholesterol.

Side Effects and Cautions

  • Soy is considered safe for most people when used as a food or when taken for short periods as a dietary supplement.
  • Minor stomach and bowel problems such as nausea, bloating, and constipation are possible.
  • Allergic reactions such as breathing problems and rash can occur in very rare cases.
  • The safety of long term use of soy isoflavones has not been established. Evidence is mixed on whether using isoflavone supplements, over time, can increase the risk of endometrial hyperplasia (a thickening of the lining of the uterus that can lead to cancer). Studies show no effect of dietary soy on risk for endometrial hyperplasia.
  • Soy’s possible role in breast cancer risk is uncertain. Until more is known about soy’s effect on estrogen levels, women who have or who are at increased risk of developing breast cancer or other hormone sensitive conditions (such as ovarian or uterine cancer) should be particularly careful about using soy and should discuss it with their health care providers.
  • Tell your health care providers about any complementary and alternative practices you use. Give them a full picture of what you do to manage your health. This will help ensure coordinated and safe care.

Soy for Post Menopausal Women

The United Soybean Board reported that research indicated that soy may contribute to heart health through a process referred to as “decreased platelet aggregation”. The researchers gave 29 post-menopausal women a daily supplement of 100 mg of isolavones or a placebo for 3 months. The subjects who received the isolavone supplement showed a significant decrease in the density of a particular platelet receptor known as TxA2. The researchers said that decreasing the density of platelet receptors reduces the risk of forming a blood clot that could lead to a heart attack or stroke.

Read More: Essential Nutrients