You're sitting in a meeting when suddenly the room heats up. You feel your face flush. Sweat trickles down your sides. You slip off your jacket and glance around. Thankfully, nobody seems to notice that you're having another hot flash.
About 3 out of 4 American women have hot flashes before and after menopause. Hot flashes can vary from a mild warmth to an intense surge of heat. They may last only a few minutes or as long as half an hour. Some women have hot flashes only once in a while. Others have them off and on throughout the day and night.
Hot flashes are caused by the drop in estrogen levels during menopause. Taking estrogen can relieve symptoms, but it may have risks, including stroke and breast cancer. This has led researchers to look for safer remedies. One that has gotten a lot of interest is soy.
Experts have been intrigued by soy because:
- Soy contains isoflavones, which are a type of phytoestrogen. Phytoestrogens are plant-based substances that act like a weak form of estrogen in the body.
- Asian women consume a lot of soy and they have far fewer hot flashes than American women.
These facts have led researchers to try to find out if consuming more soy could reduce hot flashes.
Does soy work?
So far, experts are not really sure. Some studies have shown that it provides some relief from hot flashes and other menopause symptoms. Others have found it makes no difference.
One example can highlight some common problems with studies of soy. A 2008 study showed that women who took a soy supplement had a 52 percent reduction in hot flashes. The researchers noted that this is about the same effect women get from taking an SSRI antidepressant for symptom relief without the drawbacks of SSRIs. Soy caused only minor side effects, including stomach upset, gas, and diarrhea.
- Women who took a placebo (a fake pill with no active ingredient) reported a 39 percent reduction in symptoms. So treatment reduced symptoms just 13 percent more than no treatment at all.
- The study lasted only 12 weeks. This makes it tough to know if taking the supplement longer might have had better effects or if it would have caused more problems.
- This study used one specific standardized supplement made from soy germ. The results may not hold for other forms of soy or soy from food.
This doesn't mean that soy won't help with hot flashes. It means experts aren't yet certain. If soy does help, it's also not yet clear how much to use or how long to use it.
Should I try soy for hot flashes?
It's natural to look for safe and effective ways to treat menopause symptoms. Lifestyle adjustments can help with mild hot flashes. These include getting regular exercise, practicing paced breathing, and avoiding triggers such as stress, caffeine, alcohol, and spicy foods. Adding some soy to your diet may also be worth a try.
Soybeans and soy-based foods such as tofu, tempeh, soy milk, and miso are the richest source of isoflavones. They're also found in other foods, such as legumes (peas, beans, and peanuts), flaxseed, and whole grains (such as wheat, oats, and corn). They can be part of a healthy diet.
If you have health problems, it's best to talk to your doctor before you make changes to your diet or start taking supplements. Your doctor can help you understand any special risks that you might have.
Created on 02/27/2008
Updated on 09/06/2011
- Lethaby A, Marjoribanks J, Kronenberg F, Roberts H, Eden J, Brown J. Phytoestrogens for vasomotor menopausal symptoms. Cochrane Database of Systematic Reviews. 2007. Issue 4, Art. No.: CD001395.
- Khaodhiar L, Ricciotti HA, Li L, et al. Daidzein-rich isoflavone-aglycones are effective in reducing hot flashes in menopausal women. Menopause. 2008;15(1):125-134.
- Nelson HD, Vesco KV, Haney E, et al. Nonhormonal therapies for menopausal hot flashes: systematic review and meta-analysis. Journal of the American Medical Association. 2006;295(17):2057-2071.