Soy Foods and Menopause
Hot flashes — also called night sweats when they occur during sleep — are abrupt sensations of warmth, especially in the face and neck. While the precise biological reasons why hot flashes occur in some women during menopause aren’t well-understood, it is clear that they are triggered by a decrease in estrogen production.(1)
Since estrogen declines gradually over a period of years, it’s not uncommon for women to begin experiencing hot flashes as early as two years before menopause, and to continue to experience them for several years.(2) Not all women have hot flashes, and for some, they are no more than minor annoyances. For others, however, frequent intense hot flashes can disrupt sleep and cause great discomfort throughout the day.
Preventing Hot Flashes
While estrogen therapy is the most effective treatment for hot flashes, questions about its safety have caused many women to seek alternatives. Isoflavones — a type of plant compound found in soy foods — are a popular choice for many women. Also known as phytoestrogens, isoflavones have been shown in some studies to help alleviate hot flashes without the undesirable side effects of estrogen. Cross-cultural evidence also supports this connection. For instance, in Japan — where soy foods are prominent in the diet — relatively few women experience hot flashes.(3)
More than 25 clinical studies have examined the effects of soy foods or isoflavone supplements on hot flashes.(4, 5) While not all studies have found beneficial effects, a recent analysis of the most rigorous studies concluded that isoflavones are helpful.(6) It’s not surprising that study results vary since people metabolize many compounds — including herbs, medications, and dietary supplements — differently. These variations in metabolism most likely explain why some women benefit more than others from consuming isoflavones.(7, 8) Evidence also suggests that soy foods are especially beneficial to women who have very frequent hot flashes,(6, 9) indicating that isoflavones may be particularly helpful to women who need the most relief.
Soy foods may also offer other benefits to women who are going through menopause. Many clinical studies show that isoflavone consumption, like those found in soy foods, help to inhibit bone loss in postmenopausal women.(10) Because soy protein has been shown to directly lower cholesterol,(11) substituting soy foods for many traditional dietary sources of protein may also help reduce heart disease risk. Soy foods are also low in saturated fat and cholesterol-free,(12) making them a good choice for those concerned about heart health. Soy foods may have other benefits for heart health, including improvement of endothelial functioning and a decreased risk of myocardial infarction. (13, 14)
Silk® Soymilk for Women
Silk soy products like Silk Soymilk and Silk Live!™ Soy Yogurt are ideal choices for health-conscious women of all ages. In addition to great taste, nutrition and convenience, these foods may help provide relief from hot flashes for some women. As part of a healthy diet, they can also play a role in helping to promote bone and heart health.
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2. Kronenberg F. Hot flashes: epidemiology and physiology. Ann N Y Acad Sci. 1990;592:52-86, discussion 123-33.
3. Adlercreutz H, Hamalainen E, Gorbach S, Goldin B. Dietary phyto-oestrogens and the menopause in Japan. Lancet. 1992;339(8803):1233.
4. Krebs EE, Ensrud KE, MacDonald R, Wilt TJ. Phytoestrogens for treatment of menopausal symptoms: a systematic review. Obstet Gynecol. 2004;104(4):824-36.
5. Nelson HD, Vesco KK, Haney E, et al. Nonhormonal therapies for menopausal hot flashes: systematic review and meta-analysis. JAMA. 2006;295(17):2057-71.
6. Howes LG, Howes JB, Knight DC. Isoflavone therapy for menopausal flushes: A systematic review and meta-analysis. Maturitas. 2006.
7. Rowland IR, Wiseman H, Sanders TA, Adlercreutz H, Bowey EA. Interindividual variation in metabolism of soy isoflavones and lignans: influence of habitual diet on equol production by the gut microflora. Nutr Cancer. 2000;36(1):27-32.
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9. Messina M, Hughes C. Efficacy of soyfoods and soybean isoflavone supplements for alleviating menopausal symptoms is positively related to initial hot flush frequency. J Med Food. 2003;6(1):1-11.
10. Messina M, Ho S, Alekel DL. Skeletal benefits of soy isoflavones: a review of the clinical trial and epidemiologic data. Curr Opin Clin Nutr Metab Care. 2004;7(6):649-58.
11. Zhan S, Ho SC. Meta-analysis of the effects of soy protein containing isoflavones on the lipid profile. Am J Clin Nutr. 2005;81(2):397-408.
12. Wu Z, Rodgers RP, Marshall AG. Characterization of vegetable oils: detailed compositional fingerprints derived from electrospray ionization fourier transform ion cyclotron resonance mass spectrometry. J Agric Food Chem. 2004;52(17):5322-8.
13. Hall WL, Rimbach G, Williams CM. Isoflavones and endothelial function. Nutr Res Rev. 2005;18:1-17.
14. Zhang X, Shu XO, Gao YT, et al. Soy food consumption is associated with lower risk of coronary heart disease in Chinese women. J Nutr. 2003;133(9):2874-8.