Does Soy Milk Contain Estrogen?

Soy milk does not contain estrogen. However, soy milk is made from soybeans that contain flavonoid compounds called isoflavones that exhibit a weak-estrogenic activity when ingested. Research is being conducted to evaluate the uses of isoflavones to take advantage of this estrogen activity. Some women have found relief from menopause symptoms by drinking several cups of soy milk each day.

Isoflavones

The isoflavones found in soy milk are called genistein, daidzein and glyciten. The molecules for these isoflavones are similar to estrogen and have the ability to bind to estrogen sensitive sites in your reproductive organs, brain, liver and fat cells. These compounds are also called phytoestrogens, meaning that they are plant-based compounds with weak estrogen effects, according to the the Linus Pauling Institute at Oregon State University.

Varieties

The varieties of soy milk are numerous. Manufacturers produce soy milk in flavors such as plain, vanilla, strawberry, eggnog and chocolate. Some are also available with less calories and called "light" soy milk. "Unsweetened" soy milk is also an option. You can find them in the refrigerator section of most grocery stores as well as a shelf-stable variety that does not need refrigeration until opened.

Nutrition

Soy milk is prepared by soaking soybeans in water and pulverizing them. They are strained and the resulting fluid is called soy milk. Some varieties have unrefined cane sugar added and are fortified with vitamins and calcium. It is a high-quality protein containing all the essential amino acids, omega-3 fatty acids, no cholesterol, and little or no saturated fats. Because soy milk is not from cows, it is dairy-free and contains no lactose.

It is rich in isoflavones, containing 9.65 mg total isoflavones per 100 g. One cup of soy milk has approximately 35 mg isoflavones, according to the USDA-Iowa State Data Base.

Research

Researchers are studying the potential benefits of isoflavones during menopause because of this weak-estrogen activity. According to the Aug 19, 2010 issue of "Menopause," 80 mg of isoflavones per day reduced hot flashes and insomnia symptoms in postmenopausal women. In another study published in the "Journal of the National Cancer Institute," dated 2003, a group of 21,852 Japanese females, aged 40 to 59 years showed a significant reduction in breast cancer when consuming a diet high in isoflavones.

Considerations

Always counsel with a medical professional before changing your diet and adding soy milk. Some people are allergic to soybeans and should avoid soy milk.