May 7, 2004 -- As a hot flash remedy, soy works best for women who work out, research shows.
Soy works better for some women than for others. One reason might be that processed soy loses some of its active components. Another reason might be exercise, suggest Stacy E. Panagotopulos, PhD, and Francine K. Welty, MD, PhD, of Beth Israel Deaconess Medical Center in Boston.
Panagotopulos and Welty reported their findings at this week's Arteriosclerosis, Thrombosis, and Vascular Biology Conference in San Francisco.
"Women experiencing a higher number of hot flashes who exercised more minutes and days per week received more relief from menopausal symptoms with soy consumption than those [who got less] exercise," they wrote in their presentation abstract.
Panagotopulos and Welty enlisted the aid of 60 postmenopausal women. They went on a special "therapeutic lifestyle change" diet for eight weeks. Half of them also ate 25 grams of soy protein and a half-cup of soy nuts every day. After a four-week no-soy period, they switched soy/no-soy regimens for another eight weeks.
All that soy didn't help all the women equally. For those with more than five hot flashes a day, women who exercised the most -- more than four and a half hours a week -- got the most benefit from soy. They had 49% fewer hot flashes than women who got no soy.
Less exercise also helped women with lots of hot flashes. Women who exercised 30 to 90 minutes a week -- and ate soy -- had 26.5% fewer hot flashes than women who got no soy.
It also made a difference how many days a week a woman exercised. For women with five or more hot flashes a day, exercise four or more days a week and a soy diet reduced hot flashes by 46% compared with women who got no soy. That dropped to a 25% reduction in hot flashes for women who ate soy and who averaged only one to two and a half exercise days per week.