Soybeans are a complete protein source and a dietary staple in many cultures. Soy contains phytoestrogens called isoflavones that may mimic the activity of the hormone estrogen in your body. The effects of soy isoflavones on human estrogen levels are complex. Soy is safe for everyone to consume in moderation and can have a modest effect on estrogen levels.
Phytoestrogens are compounds found in plants that are chemically similar to the hormone estrogen. Normally thought of as involved in female reproduction, estrogens control many important aspects for the body in men and women: metabolism, bone and blood vessel health, skin tone, cholesterol level, fluid balance and sexual desire. Soy is one of the richest sources of phytoestrogen, containing the highest levels of isoflavones in food.Watch movie online A Cure for Wellness (2017)
Soy isoflavones activate your body’s estrogen receptors, proteins that detect the presence of estrogen and carry out effects such as changes in gene expression. However, isoflavones do so more weakly than your body’s natural estrogen. If estrogen is absent, isoflavones weakly activate the estrogen receptor, mitigating the effect of low estrogen. If estrogen is abundant, isoflavones interfere with the activity of natural estrogen, limiting the effect of high estrogen levels. Since the structure of isoflavones is similar to estrogen, isoflavones may decrease your body’s production of estrogen and increase the rate of estrogen degradation due to feedback mechanisms that control estrogen levels.
People may process soy isoflavones and other phytoestrogen in different ways. Isoflavones exist naturally in a form called a glycoside, which is linked to a sugar. The sugar must first be removed before it can be well absorbed and show hormonal activity. This is accomplished by the bacteria and enzymes in your intestines or via fermentation of soy products such as miso. The structure of the isoflavone may also be altered during this process. Only one-third of people with Western ancestry metabolize isoflavones into a form with high estrogenic activity, according to the Linus Pauling Institute.
Soy isoflavones do not appear to be helpful in the treatment or prevent or breast or prostate cancer, according to the Linus Pauling Institute. The cholesterol-lowering effect of isoflavones is modest, resulting in only a 3-percent reduction in bad cholesterol. Isoflavones may reduce menopausal symptoms and improve bone density in those at risk for osteoporosis, though results are inconsistent. The safety of soy isoflavone supplements has not been well studied, though dietary consumption of soy is safe.