= Full article availableThe drop in estrogen levels at menopause is followed by a range of adverse changes, including bone loss, rising blood cholesterol levels, and, less predictably, declining cognitive function. To counteract these effects attributed to loss of estrogen, many women have turned to soy, perhaps even more so in the wake of research that strongly suggests women should try to avoid hormone replacement therapy over the long term because it can increase the risk both for heart disease and breast cancer.
Soy contains estrogen-like components called isoflavones. And in preliminary investigations, at least, iso-lavones have shown some promise in the areas of bone density, cholesterol, and cognitive function. But a recent study from the University Medical Center at Utrecht in the Netherlands provides disheartening results.
The study involved 200 women between the ages of 60 and 75, with half taking a soy protein supplement for one year and the other half taking a placebo. (Neither the women nor the investigators knew who was in which group.) The women in the soy group took 25.6 grams of soy protein daily containing 99 milligrams of iso-flavones in powder form that could be mixed with food or drink. That’s a high amount, significantly more than you’d get in the traditional Japanese diet.
Both at the start of the study and after a year of supplementation, the investigators assessed the women’s cognitive function through a battery of tests. They also measured bone mineral density at the hip and spine and measured blood lipid levels. The result: there was no significant difference between treated and placebo groups in cognitive function, bone mineral density, or cholesterol. In short, women derived no benefits in those measurements from taking daily soy protein supplements for a year.
The researchers point out that timing may be a crucial factor when it comes to taking soy. The women in the study had an average age of 66 and had been postmenopausal for an average of 18 years, so it may have been too late to reverse adverse health effects of menopause. Further research is necessary to determine if supplementation with soy earlier in life proves more effective.
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