Researchers from Pharmavite and its parent company Otsuka Pharmaceutical Co. report that 10 milligrams per day of the S-equol supplement could reduce the symptoms of menopause to a level similar to 50 mg of a soy isoflavone supplement, according to findings published in the Journal of Women's Health.
“This study provides evidence that daily doses of the supplement S-equol, a metabolite of the soy isoflavone daidzein, reduced hot flash frequency and relieved muscle and joint pain in U.S. postmenopausal women,” said Belinda H. Jenks, Ph.D., coauthor of the study and director of Scientific Affairs & Nutrition Education at Pharmavite LLC.
“These findings confirm earlierstudies in Japanese women documenting S-equol's ability to relieve menopausal symptoms.”
According to the company, the supplement is produced by fermenting whole soy germ with Lactococcus 20-92 using a patented and proprietary process by the Otsuka Pharmaceutical Co. to convert daidzein to S-equol.
The S-equol ingredient is created under current Good Manufacturing Practices (cGMP) and is self-affirmed GRAS (Generally Recognized As Safe).
Jenks and her co-workers recruited 102 US postmenopausal women aged between 45 and 65 who experienced more than 35 hot flashes weekly, and randomly assigned them to receive either the S-equol supplement at a dose of 10, 20 or 40 mg per day or a supplement containing soy isoflavones at a dose of 50 mg per day.
After eight weeks, the researchers found no significant differences between the groups, indicating that all the S-equol groups experienced similar reductions in various menopause symptoms as the standardized soy isoflavone supplement.
Indeed, the number of hot flashes decreased from an average of 10 per day at the start of the study to between 6.3 and 6.9 per day for the S-equol groups, while the soy isoflavone group averaged 7 per day.
In addition, muscle and joint pain improved significantly for both the 10 and 20 mg doses of S-equol, compared with the soy isoflavones.
In terms of tolerability and safety, no significant changes were recorded in the women's laboratory blood or urine tests, hormone levels, electrocardiographs, physical examinations or vital signs, said the researchers.
Commenting on the potential muscle and joint benefits, Jenks said that muscle stiffness and muscle pain can result from impaired local blood flow and that both soy isoflavones and S-equol may affect blood flow.
“S-equol, 10 mg/day, appears to be as effective as soy isoflavones at reducing hot flash frequency and more effective for relieving muscle and joint pain in postmenopausal women,” concluded the researchers.
“S-equol, greater than 20 mg/day, alleviates hot flashes to a greater extent than soy isoflavones in those women who experience more than 8 hot flashes per day.”
Source: Journal of Women's Health
Published online ahead of print, doi: 10.1089/jwh.2011.3153
“A Pilot Study on the Effects of S-Equol Compared to Soy Isoflavones on Menopausal Hot Flash Frequency and Other Menopausal Symptoms”
Authors: B.H. Jenks, S. Iwashita, Y. Nakagawa, K. Ragland, J. Lee, W.H. Carson, T. Ueno, S. Uchiyama