Soy supplements are nutritional products that are made from substances found in soybeans such as soy protein. The soybean is a plant that is native to the southeastern part of Asia, and soybeans are grown commercially in many parts of the world. Soy protein is a powdered form of soy that is commonly found in soy supplements and is used as a source of dietary protein by many people. Isoflavones are substances in soy that typically change to phytoestrogens after they enter the body. Phytoestrogens are similar to the human estrogen hormone and can have effects on the body that are similar to estrogen.
Many foods contain soy protein from soy supplements. Protein from soy includes all of the essential amino acids that people typically need from sources of protein in most cases. People consume many foods made from soy for their protein content, including tofu, soy veggie burgers and soy energy bars. Soy milk, soy ice cream and soy cheese are other food products that contain soy supplements.
Some people use soy supplements, soy foods and soy products to improve their health. Soy protein may reduce cholesterol levels in people with high levels of bad cholesterol in their blood. In some cases, cholesterol-lowering effects of soy can contribute to improved cardiovascular health. Infants with diarrhea or lactose intolerance may experience some relief from these conditions with the help of soy protein. Soy protein has helped reduce blood-glucose levels in some diabetics.
Many women have used soybeans and soy products to relieve hot flashes and other symptoms of menopause. Osteoporosis in some postmenopausal women may be improved with intake of soy supplements that contain isoflavones. Consumption of soy early in life lessens the chance that a woman will develop breast cancer in some instances. Phytoestrogens from soy may prevent migraines from occurring during menstruation.
Soy supplements can cause side effects in some individuals who are allergic to soy. People with allergies to soy may experience an allergic reaction after eating soy foods that may include a runny nose or declining blood pressure. Some people experience gastrointestinal effects from soy protein consumption such as constipation, nausea and bloating. Individuals with hypothyroidism may experience a worsening of the condition from consuming soy products. The estrogenic effect of isoflavones in soy products can increase tumor growth in some patients who have cancers that are sensitive to hormones such as uterine, ovarian or breast cancer.
In some cases, soy supplements may interfere with prescription drugs and cause unwanted interactions. Estrogen pills can become less effective in some women if these pills are taken concurrently with large amounts of soy. Soy may reduce the blood-thinning effects of the medication warfarin and increase the risk of blood-clot formation. Many patients who take prescription medications can benefit from a discussion with a doctor about potential interactions between soy and the drugs they take.