By Kerry Grens
NEW YORK (Reuters Health) - Menopausal women who took soy supplements during a two-year trial reported no differences in quality of life compared to their counterparts taking placebo pills, U.S. researchers report.
It's possible that soy could still offer women some benefits through menopause, said the study's lead author Dr. Paula Amato, from Oregon Health and Science University in Portland, "but I think if you are similar to the subjects in the study, then probably taking supplements isn't going to make a huge impact on your quality of life."
In light of health concerns attached to taking hormones, soy has been seen as an attractive alternative for relieving menopausal symptoms. But research on the effectiveness of soy extracts for hot flashes and other bothersome symptoms has yielded conflicting results so far.
In the new report, published in the medical journal Menopause, Amato and her colleagues looked not just at specific symptoms but overall quality of life measures among healthy women, mostly in their 50s and six years or more into menopause on average.
Several hundred women were asked to take supplement pills three times a day for two years. Among them, 126 took a fake supplement that contained no soy extract, while 135 women took tablets containing a total of 80 milligrams a day of soy protein and another 123 women took 120 mg each day.
At the start of the study and again one and two years into it, the women filled out a quality of life survey that asked about mental, physical and sexual health as well as about hot flashes.
In each of the surveys, the women in all three groups scored similarly on the main measures in the questionnaire.
"From our study and the good amount of the literature to date it appears that taking soy supplements after menopause does not improve quality of life," said Amato. "We can't really recommend it to our patients."
Mark Messina, president Nutrition Matters and an adjunct professor at Loma Linda University in California, cautioned against concluding that the key ingredients in soy supplements, known as isoflavones, don't have any effect on hot flashes, however.
"Unfortunately, because of the severe limitations of this study, very little if anything can be learned about isoflavones and hot flashes," Messina wrote in an email to Reuters Health.
For one, he said, the levels of a particular type of isoflavone - called genistein - were lower than in other studies that have found benefits from soy extracts.
Additionally, the researchers originally set out to look at the effects of soy extracts on bone health, and did not recruit women specifically with hot flash or quality of life concerns in mind.
"So in my opinion, no useful information about isoflavones and hot flashes is provided by this study," said Messina, who regularly consults for companies that make or sell soy foods and supplements.
Isoflavone companies market the supplements, sold for about $17 for 90 50-mg pills, as "potentially" easing the changes associated with menopause.
Amato agreed that the study has some limitations, and that the findings can't be generalized to all forms of soy in all types of women.
For instance, "taking supplements just might not be the same as eating a high soy content diet your entire life," she told Reuters Health.
But "if you look at this specific supplement for this particular group of women for this reason, quality of life, I'm convinced by this study it's not terribly helpful," she added.
SOURCE: http://bit.ly/UsyPIY Menopause, online December 3, 2012.