Hot flashes are the most common symptom of menopause in 50-70% of menopausal women in developed countries and estrogen hormone replacement therapy is highly effective in alleviating these symptoms. However, in recent years the use of estrogen hormone therapy has been substantially reduced due to the finding in the large Women’s Health Initiative study that it increases risk of stroke and breast cancer. Thus, there is a need for a safe and non-hormonal alternative for hot flashes. One of the most highly studied alternatives is soybean isoflavones. It was suspected that soybeans contain compounds to help reduce menopausal symptoms since Asian countries where soybean consumption is much higher than in Western counties only 20-25% of postmenopausal women experience hot flashes.
Soy isoflavones are naturally occurring in soybeans and consist of three compounds called genistein, daidzein, and glycitein which make up approximately 50%, 40%, and 10% of the total soybean isoflavone content, respectively. Since the mid 1990s, dozens of studies have been conducted with isoflavones to determine if they will alleviate menopausal symptoms. Yet the findings have been very mixed and it was it was proposed only recently that soy products with genistein as the predominate isoflavone were consistently effective and those with daidzein as the predominate isoflavone were mostly ineffective. This proposal has now been confirmed in four clinical intervention studies with postmenopausal women given pure genistein.
Two studies were conducted in Sicily with postmenopausal women given a pure natural genistein extract for 1 and 2 years, respectively. In the first study published in 2004 by Crisafulli and coauthors in the journal Menopause, 98 postmenopausal women suffering from approximately 5 hot flashes per day were given a daily dose of 54 mg of genistein or a placebo for 12 months. After 3, 6 and 12 months the women given genistein had statistically significant reductions by comparison to placebo of 22, 29 and 24%, respectively. The same group conducted a much larger study with 389 postmenopausal women over 2 years given 54 mg/day of genistein or a placebo. The one year results published in 2007 by D’Anna and coauthors in Menopause showed effectiveness in the genistein group after one month which reached its peak after 12 months at 56.4% reduction in hot flashes. The second year of the study published by D’Anna and coauthors in a 2009 issue of Menopause showed no further decrease after 24 months beyond the 56.4% decrease seen at 12 months. A third study also conducted in Italy by Albertazzi and coauthors and published in Climacteric in 2005 gave 90 mg/day of genistein or placebo to 100 postmenopausal women in a crossover study for 6 weeks. Although there was no effect of genistein on hot flashes in the entire group, women who had more than 9 hot flashes per day had a 31.25% reduction in the genistein group compared to a 20% reduction in the placebo group.
A fourth clinical intervention study with a pure synthetic genistein was competed and reported by Elliott and coauthors in 2009 and is currently in press. In this placebo-controlled study 84 postmenopausal women received 30 mg of genistein or a placebo for 12 weeks. After 12 weeks the women on genistein had a 51% reduction on hot flashes compared to only 27% for the women in the placebo, a highly significant difference. Compared to placebo, this reduction in hot flashes at 12 weeks (51-27%) was a net reduction of 24% which is very similar to the 29% net reduction seen in the study of Crisafulli and coauthors. What is particularly noteworthy about this study is that the dose was 30 mg versus 54 mg in the Sicily studies and a daily genistein intake of 30 mg falls well within the range consumed by Asians who eat traditional soy foods. The genistein used in this study is branded as geniVida®, a product of DSM Nutritional Products. It is 99% pure, soy-free, allergen-free and has an extensive package of safety studies in animals and humans which demonstrate it is safe for daily use.
The geniVida® used in the above study is now available in GEM Keep it cool.™
About the Author:
Dr. Elliott has been a clinical nutrition researcher in the food and nutritional supplement industries for over 40 years. During this time, Dr. Elliott has helped develop a number of the leading nutritional health products found on the market today.