DaidzeinEquilibrium™ is a supplement containing equol, which may have beneficial effects for men with prostate problems and women with menopausal symptoms.  Equol is produced by bacteria in the intestines from daidzein (an isoflavane pictured at left).  Some people produce it naturally when eating foods from the legume family that contain daidzein. The richest sources are soy beans, fava beans and kudzu. Smaller quantities are also found in peas, other beans and red clover (also in the legume family). There are also small amounts in grains, nuts, coffee, tea and currants.

Twenty-one strains of intestinal bacteria have been identified that can transform daidzein to equol or an intermediate compound. Only about 25-30 percent of people in Western countries appear to be able to make this conversion as opposed to 50-60 percent of people from Asian countries like Japan, Korea and China.

Consuming xylitol appears to enhance the conversion because it encourages the growth of bacteria that convert daidzein to equol. [See: Xylitol affects the intestinal microbiota and metabolism of daidzein in adult male mice.] Consuming seaweeds also appears to enhance conversion, which may explain the higher rates of conversion among Asians. [See: Dietary seaweed modifies estrogen and phytoestrogen metabolism in healthy postmenopausal women.]

Equol comes in two forms, which are mirror images of each other S-equol and R-equol. Only the S-form is produced in the human body. S-equol is of interest to researchers because it is a phyotoestrogen and appears to have beneficial effects on the human body.

Equol and Prostate Health

One of the potential benefits of equol is its ability to bind to DHT (dihydrotestosterone). This metabolite of testosterone stimulates prostate growth. As men age DHT can cause the prostate to enlarge, a condition known as benign prostatic hyperplasia (BPH). Located underneath the bladder, as the prostate grows in size it impedes urination. An estimated 50% of the male population have BPH by age 50 and 75% of men have it by age 80.

Normal and enlarged prostateSymptoms of BPH can include frequent urination, an urgency to urinate, dribbling, frequent nighttime urination, urinary stream hesitancy (needing to wait for urination to start), intermittency (the urine stream stops and starts) and straining to void urine. This difficulty with urination can increase the risk of urinary tract infections and the formation of bladder stones. It can also cause distention (stretching) of the bladder, which can weaken the bladder muscle.

Most drugs for BPH work by blocking the enzyme that converts testosterone to DHT. Unfortunately, this enzyme is also involved in numerous other body processes, so side effects are numerous. Equol has the ability to help BPH by binding to DHT, blocking its ability to stimulate prostate growth. It also binds to certain types of estrogen receptors that further blocks the adverse effects of androgens without interfering with normal testosterone metabolism.

Besides helping with BPH, equol may also have benefits in reducing prostatitis (inflammation of the prostate). It may also reduce the risk of prostate cancer (malignant neoplasms or carcinoma of the prostate). 

Equol and Cancer

Cancers of the breast, prostate and uterus are often estrogen-dependent, meaning estrogen stimulates their growth.  Certain phyotoestrogen compounds in plants, including the flavones from soy and the lignans from flaxseed appear to bind to estrogen receptors and reduce the estrogen-stimulating effects. Equol may have this benefit.  One study suggested that equol may prevent breast cancer cells from proliferating, which could be helpful in inhibiting the spread of breast cancer.

It may also be helpful for other types of cancer, too. [See: Emerging research on equol and cancer.] One study showed that it induced apoptosis (programmed cell death) in hepatic cancer cells.  [See: Equol induces apoptosis in human hepatocellular carcinoma SMMC-7721 cells through the intrinsic pathway and the endoplasmic reticulum stress pathway.]

The results of studies linking isoflavones like equol with reduced risk of cancer are somewhat mixed.  Some studies suggest that under the right conditions, soy isoflavones can stimulate estrogen-dependent cancers. Three recent studies using animal models of breast cancer found that S-equol did not stimulate the growth of breast tumors, however.

Soy isoflavones do appear to have a mild thyroid inhibiting effect, but Asian women who eat soy also tend to eat a lot of iodine-rich seaweeds. Since iodine can also be helpful in treating breast cancer and it increases the conversion of daidzein into equol, the consumption of seaweeds and soy together may be a critical factor in reduced risk of breast cancer among Asian women.

Equol and Menopause

Equol may have some benefits for menopausal women. Two placebo controlled clinical trials giving equol as a supplement to non-equol producing Japanese women showed modest improvement in menopausal symptoms. [See: New equol supplement for relieving menopausal symptoms: randomized, placebo-controlled trial of Japanese women.] A non-placebo controlled trial on American women showed similar results. There was a reduction in hot flashes, joint pains and muscle stiffness. There was also an improvement in mood. So Equol isn’t just for men. It could be taken with Flash-Ease to possibly potentize its effects for women who are having problems with hot flashes and other menopausal symptoms.

Other Potential Benefits

Equol has antioxidant, anti-inflammatory, and vasorelaxant properties, suggesting it may help reduce the risk of cardiovascular disease. It may increase nitric oxide production, which dilates arteries. This means it could be helpful in some cases of high blood pressure or erectile dysfunction.

There is also some research suggesting that equol may help with the hyperinsulinemia associated with metabolic syndrome.  It appears to help cells metabolize glucose. [See: Antihyperglycemic effect of equol, a daidzein derivative, in cultured L6 myocytes and ob/ob mice.]  One study showed that pregnant women had fewer indicators of metabolic syndrome (cardiometabolic risk) with higher levels of equol. [See: Urinary isoflavone concentrations are inversely associated with cardiometabolic risk markers in pregnant U.S. Women.]

There is also interest in using S-equol for improving the appearance of aging skin. This is not a well-tested hypothesis, however. It may also have a role in reducing the risk of osteoporosis, but the research here is also unclear.

Supplementing with Equol

Taking 8-15 milligrams of S-equol daily corresponds to the amount of equol produced by consuming 6-11 grams of soy daily in equol producers. Each capsule of Equilibrium™ contains 6 mg. of equol, so two capsules will provide 12 milligrams daily. The half-life of equol is 7-8 hours, which means that the body secretes half of it within that time period, so it’s best to take one capsule in the morning and one in the evening, as this well keep the blood levels of equol fairly stable.

Although some benefits of equol may be noticed within a few days, it usually takes 4-6 weeks of supplementation to begin to see a difference. Best results are obtained after 3-6 months supplementation. Research shows that equol is well-tolerated, so taking it consistently for many years should not be a problem.

Additional References

In addition to the studies cited above, here are some general sources for more information on equol.

Equol for Prostate and Urinary Health: A general reference to the potential benefits of equol for men.

Genistein and daidzein should be avoided for breast cancer: This is a good summary of research concerning isoflavones, including equol, on cancer.  Although it concludes women with breast cancer should not take genistein or daidzein supplements, there are some favorable studies for equol.

http://en.wikipedia.org/wiki/S-equol: Although Wikipedia isn't considered the most reliable source of information, this article appears to be well-written and cites many studies on S-equol.