What is Soy Isoflavones for?
Soy comes from soybeans. The beans can be processed into soy protein, which is a powder; soymilk, which is a beverage that may or may not be fortified with extra calcium from the soybeans; or soy fiber, which contains some of the fibrous parts of the bean.
Soy is used for high cholesterol, high blood pressure, and preventing diseases of the heart and blood vessels. It is also used for type 2 diabetes, asthma, lung cancer, endometrial cancer, prostate cancer, and thyroid cancer, as well as preventing weak bones (osteoporosis), and slowing the progression of kidney disease.
Other uses include treating constipation and diarrhea, as well as decreasing protein in the urine of people with kidney disease, improving memory, and treating muscle soreness caused by exercise.
Women use soy for breast pain, preventing breast cancer, preventing hot flashes after breast cancer, menopausal symptoms, and premenstrual syndrome (PMS).
In foods, soy is used as a milk substitute in infant feeding formulas, and as an alternative to cow's milk. Soybeans are eaten boiled or roasted. Soy flour is used as an ingredient in foods, beverages, and condiments
The active ingredients in soy are called isoflavones. A study of the quality of commercially available soy supplements suggests that less than 25% of products contain within 90% of labeled isoflavone content. Paying more for a product doesn’t necessarily guarantee that the content shown on the label is accurate.
What is Soy Isoflavones Possibly Effective for?
• Preventing thyroid cancer. Getting a lot of soy from the diet might help to prevent thyroid cancer.
• Endometrial cancer. There is some evidence that increasing soy intake might lower the risk of endometrial cancer. Endometrial cancer is less common in Japan, China, and other Asian countries where the usual diet is low in calories and high in soy and whole grain foods, vegetables, and fruits.
• Lung cancer. Research suggests that men and women who consume a higher amount of dietary phytoestrogens, such as isoflavones from soy, are less likely to develop lung cancer than people who consume smaller amounts. Soy seems to prevent lung cancer more in men than women.
• Prostate cancer. Research on the effect of soy on prostate cancer risk has been mixed. Men who eat an Asian diet, which contains 10 times more soy than the average American diet, seem to have a lower risk of prostate cancer. But, it's unclear whether it’s the soy in the diet of Asian men or other factors (such as genetic differences or differences in dietary fat) that protect against prostate cancer.
• Improving memory. Some research suggests that a high soy diet might slightly improve performance on memory tests.
• Reducing breast pain. There is some limited evidence that soymilk (34 grams soy protein/day) might reduce monthly breast pain in some women.
• Weight loss. Limited evidence suggests that eating soy protein along with a low-calorie diet for six months seems to reduce weight in obese and overweight people more than a low-calorie diet alone.
• High blood pressure. Some evidence suggests that eating soy protein might reduce systolic blood pressure (the top number in a blood pressure reading) by about 4 mmHg and diastolic blood pressure (the bottom number) by about 3 mmHg in people with pre-high blood pressure or mild high blood pressure. This is a relatively small reduction.
• Premenstrual syndrome (PMS).