Genistein's therapeutic uses
Genistein is a natural compound found primarily in soy and is recognized for its potential therapeutic uses across various health conditions. As a phytoestrogen, it mimics estrogen's effects in the body, which can be beneficial for conditions like menopausal symptoms and osteoporosis due to its ability to partially mitigate the effects of estrogen when levels are high and supplement them when low. Research suggests that genistein may play a role in preventing heart disease, improving blood sugar control in prediabetes, and even reducing cancer risk, although the evidence varies in strength.
Clinical studies indicate that genistein can improve bone density in postmenopausal women and alleviate hot flashes, with some studies also showing positive impacts on cognitive function in aging populations. While many of genistein's benefits are associated with its anti-inflammatory properties, caution is advised due to potential gastrointestinal side effects and concerns regarding immune function. Overall, genistein presents a promising area of research, particularly for those interested in natural health solutions, but further studies are necessary to fully understand its efficacy and optimal dosages.
Genistein's therapeutic uses
- DEFINITION: Natural plant product used to treat specific health conditions.
- PRINCIPAL PROPOSED USES: None
- OTHER PROPOSED USES: Amyotrophic lateral sclerosis, blood sugar control (prediabetes), cancer prevention, cognitive function, high cholesterol, menopausal symptoms, osteoporosis, weight management
Overview
Genistein, a naturally occurring chemical in soy, has attracted scientific interest for its possible benefits in cancer and heart disease prevention. Genistein is a phytoestrogen, an estrogen-like substance in some plants. There are two main types of phytoestrogens: isoflavones and lignans. Soy is the most abundant source of isoflavones, with genistein being the most abundant isoflavone in soy. Red clover is also a good source of genistein.
Like other phytoestrogens, genistein can work in two ways: increasing or decreasing the effects of estrogen. This happens because genistein binds to special sites on cells called estrogen receptors. Genistein stimulates these receptors, but not as strongly as real estrogen; at the same time, it blocks estrogen itself from attaching. The net result is that when there is a lot of estrogen in the body, such as before menopause, genistein may partly block its effects. Since estrogen appears to increase the risk of various forms of cancer, regular use of genistein by premenopausal women might help reduce this risk. On the other hand, if there is little human estrogen present, such as after menopause, genistein can partly make up for it. This is one rationale for using genistein to treat menopausal symptoms and to prevent osteoporosis. Genistein might also help reduce heart disease risk and cancer.
Requirements and Sources
Genistein is found in high quantities in soy and in negligible quantities in a few other foods. Most soy foods contain about 1 to 2 milligrams (mg) of genistein per gram of protein.
Therapeutic Dosages
The optimum dosage of genistein is unknown. In Asia, population groups that daily eat soy foods containing 20 to 80 mg of genistein have lower rates of breast and prostate cancer than do groups in the West with less genistein in their diets. However, it is not known if genistein or even soy isoflavones are generally responsible for this effect.
Therapeutic Uses
Double-blind, placebo-controlled studies have found that genistein may help prevent heart disease and prevent or treat osteoporosis. Genistein may additionally improve blood sugar control in people with prediabetes. Weaker evidence suggests potential benefits in cancer prevention, cancer treatment, and amyotrophic lateral sclerosis (ALS).
Isoflavone mixtures containing genistein have undergone considerably more study than genistein alone. Mixed isoflavones have shown promise for most of the conditions just mentioned, as well as for menopausal symptoms and cyclic mastalgia. Genistein has also shown positive results in studies on improving cognitive function in aging populations and aiding in weight management in post-menopausal women.
Scientific Evidence
Osteoporosis. Estrogen has a powerful protective effect on bone. In women, osteoporosis often occurs after menopause, when the ovaries stop producing estrogen. Animal studies and double-blind, placebo-controlled trials in humans suggest that genistein can help restore bone protection. For example, in a twenty-four-month double-blind, placebo-controlled study of 389 postmenopausal women with mild bone loss, genistein at a dose of 54 mg daily significantly improved bone density compared with a placebo. (All participants were additionally given calcium and vitamin D.)
In a previous twelve-month study, ninety women aged forty-seven to fifty-seven were given genistein, standard hormone replacement therapy (HRT), or a placebo. The results showed that genistein increased bone density to approximately the same extent as HRT. No adverse effects on the uterus or breast were seen. Evidence suggests that unlike estrogen, which primarily helps prevent the destruction of bone, genistein may also assist in creating new bone.
However, in one animal study, while a small dose of genistein helped protect the rats’ bones, a larger dose of genistein seemed to have the opposite effect, causing increasing bone destruction. Human studies are needed to determine whether genistein is truly effective and to find the optimum dose. Other studies have evaluated the effects of soy products containing other constituents besides genistein.
Menopausal symptoms (hot flashes). A double-blind study of 247 women suffering from menopausal hot flashes compared the effects of a placebo and genistein over one year. Genistein was taken at a dose of 54 mg per day. The results indicated that genistein significantly reduced hot flashes compared with the placebo. No adverse effects were seen.
Cancer. Genistein may help reduce the risk of various forms of cancer. In one study, newborn female rats treated with genistein had less breast cancer later in life than those treated with a placebo. However, other studies suggest that genistein or other isoflavones could promote breast cancer under certain conditions.
In the test tube, genistein has been found to suppress the growth of a wide range of cancer cells, including cancer forms that are unaffected by estrogen. For example, genistein has been found to inhibit skin cancer when it is applied to the skin of mice or fed to rats. Furthermore, in test-tube studies, genistein has been found to enhance the effects of chemotherapy drugs. These benefits are likely due to genistein's anti-inflammatory properties. Further, genistein’s anti-inflammatory properties may also have broad health benefits and protect from developing chronic diseases.
Heart disease. One double-blind, placebo-controlled study found that the use of genistein helped relax the artery wall (the endothelium), an effect that would be expected to help prevent heart disease. In addition, test-tube studies suggest that genistein may help keep cholesterol in the blood from being deposited in blood vessel walls. Finally, one test-tube research study suggested that genistein may also inhibit the formation of blood clots, which are a major cause of heart attacks.
In a double-blind, placebo-controlled trial in which participants with Alzheimer’s disease were given genistein for twelve to eighteen months, positive effects were found in cognitive function and memory in a group supplemented with genistein. Additional human studies have shown that genistein may be beneficial in increasing weight loss among postmenopausal women.
Safety Issues
Most safety studies that have implications for genistein involved mixed isoflavones from soy or red clover. Regarding genistein alone, one large study reported that genistein caused significant gastrointestinal side effects in almost 20 percent of participants.
Additionally, some evidence suggests that genistein, in particular, might impair immunity. One study in mice found that injected genistein has negative effects on the thymus gland (an organ that is important for immunity) and also causes changes in the prevalence of various white blood cells consistent with impaired immunity. Although the genistein was injected rather than administered orally, the blood levels of genistein that these injections produced were not excessively high. They were comparable to (or even lower than) what occurs in children fed soy milk formula. Additionally, there are several reports of impaired immune responses in infants fed soy formula. While research has not confirmed that genistein impairs immunity, these findings are a potential cause for concern.
Bibliography
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