Equol

Equol (4',7-isoflavandiol) is an isoflavandiol metabolized from daidzein, a type of isoflavone, by bacterial flora in the intestines. While endogenous estrogenic hormones such as estradiol are steroids, equol is a non-steroidal estrogen. However, only about 30-50% of people have intestinal bacteria that make equol. Equol can exist in two enantiomericforms, (S)-equol and (R)-equol. (S)-Equol preferentially binds estrogen receptor beta.

Mammary gland differentiation by early life exposure to enantiomers of the soy isoflavone metabolite equol.

Identification of a Novel Dihydrodaidzein Racemase Essential for Biosynthesis of Equol from Daidzein in Lactococcus sp. Strain 20-92

Equol, a natural estrogenic metabolite from soy isoflavones: convenient preparation and resolution of R- and S-equols and their differing binding and biological activity through estrogen receptors alpha and beta.

BPH

Equol is a novel anti-androgen that inhibits prostate growth and hormone feedback.

Cancer

The chemopreventive action of equol enantiomers in a chemically induced animal model of breast cancer.

Cardiovascular

'Equol' may determine if soy protects your heart

Research protocol: effect of natural S-equol on blood pressure and vascular function- a six-month randomized controlled trial among equol non-producers of postmenopausal women with prehypertension or untreated stage 1 hypertension

Equol is more active than soy isoflavone itself to compete for binding to thromboxane A(2) receptor in human platelets, indicating it is superior as an anti-thrombotic.

Study:

Background

Although higher habitual soy intake is associated with lower blood pressure (BP) and stroke incidence, clinical trials using soy protein or isoflavones on cardiovascular risks yielded inconsistent results. The discrepancies are hypothesized to be due to the individuals’ intestinal bacterial capacity to metabolite isoflavones daidzein into equol. Animal and in vitro studies have revealed that equol has stronger estrogen-like and anti-oxidative activity than isoflavones and possesses natriuretic and vasorelaxant properties which may play an important role in the prevention of hypertension. However, no clinical trial has examined the effect of equol on BP. We thus propose a 24-week randomized controlled trial to test the effectiveness of natural S-equol on BP and vascular function among equol non-producers.

Menopause

Isoflavone supplementation improves menopausal symptoms only in women with the ability to produce equol.

Osteoporosis

• Impact of equol-producing capacity and soy-isoflavone profiles of supplements on bone calcium retention in postmenopausal women: a randomized crossover trial
• Equol and genistein compare favorably with hormone replacement therapy (estradiol) on bone quality in a rat osteopenia model.
• Genistein and equol positively effect bone quality and quantity in osteoporotic mice.
• The phytoestrogen equol is able to improve fracture healing in ovariectomy-induced osteoporotic bones.
• Equol and resveratrol improve bone turnover biomarkers in postmenopausal women.

Urge Incontinence

The phytoestrogens equol, genistein and puerarin may be beneficial for prevention or therapy of postmenopausal urge incontinence.

Uterine Fibroids

• There is a modest inverse association between lignan excretion and uterine fibroid risk.

Other Effects

• The soybean isoflavone equol blocks ritonavir-induced endothelial dysfunction.