Soy isoflavones are a class of secondary metabolites formed during the growth of soybeans. Their structure is similar to that of estrogen and they have strong biological activities, such as estrogen-like and anti-estrogenic activities, antioxidant activities, and enzyme inhibitor activities, and therefore, are closely related to human health. There are 12 types of naturally occurring soy isoflavones, 97% to 98% of which are glycosidic soy isoflavones or their derivatives in the form of β-glucoside, and only about 2% to 3% are free glycosides. Soy isoflavones in fermented soy foods exist as free glycosides and are easily digested and absorbed by the human body, which can play a very good role in health care. Soy isoflavones have the following physiological functions due to their unique characteristics.
Beauty and skin care
Scientists are currently developing a beauty product that has cosmetic value and no side effects - a phytoestrogen preparation. This phytoestrogen is an isoflavone extracted from soybeans, which is known as a health messenger for beauty and skin care. It has estrogen-like effects without the toxic side effects of estrogen, such as nausea, loss of appetite, swollen breasts and irregular menstruation, and is a top product for beauty and anti-aging skin.
Prevention of cardiovascular diseases
When women enter menopause, the synthesis and secretion of estrogen levels in the body are insufficient, and the decline of estrogen can lead to a malfunction in cholesterol metabolism, resulting in an increase in cardiovascular disease morbidity and mortality due to elevated fat and cholesterol in menopausal women. According to statistics, the incidence of coronary heart disease in menopausal women increases 2-3 times compared to pre-menopausal women. The risk of cardiovascular morbidity decreases by 35% to 50% after consuming estrogen replacement therapy (ERT) in menopausal women. Studies suggest that soy isoflavones, which have estrogenic activity, may play an important role in the prevention of cardiovascular disease in women.
Prevention of breast cancer
There are many epidemiological investigations about soy intake and breast incidence. Through long-term epidemiological surveys, it was found that soy milk intake was negatively correlated with breast cancer incidence. According to the survey, the relative risk of breast cancer tends to decrease as the daily soy intake or the annual number of soy products consumed by the population increases.
Prevention of hot flashes and osteoporosis
After menopause, the decline in estrogen levels in women can cause a series of menopausal symptoms characterized by hot flashes and sweating. Continued bone loss is a natural process of aging, and the incidence of osteoporosis is higher in older women than in men. One of the main reasons for this is the rapid decline in estrogen levels after women enter menopause, which accelerates bone loss.
Prevention and treatment of prostate cancer
Prostate cancer is the most common type of non-skin cancer. Although men of all ages can develop this disease, the incidence is higher over the age of 50. The reason why Europeans and Americans have a higher rate of prostate cancer is that Europeans and Americans do not consume as many soy products as Easterners. Tofu, soy milk, etc. are not only beneficial in reducing the incidence of prostate cancer, but also have the effect of prolonging the lives of prostate cancer patients.
