Why do 85 percent of menopausal women suffer hot flashes in some countries but only 15 percent in others?
Menopausal Hot Flashes Are Not Inevitable
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
SWAN, which stands for Study of Women’s Health Across the Nation, is by far the largest evaluation of menopausal symptoms in history, studying 16,000 American women between the ages of 40 and 55. They found that women over a body mass index of 27 or higher were significantly more likely to suffer from hot flashes or night sweats, stiffness or soreness, and urinary leakage. A BMI over 25 is considered overweight; 30 is obese; and the average U.S. BMI is 29.8. Since fatty tissue is a source for estrogen, one might expect the reverse. But the link between excess body fat and worse menopausal symptoms indeed seems causal, since women randomized to a weight loss intervention experience significant improvement in hot flashes––an effect that may extend to bariatric surgery.
In the SWAN study, smoking and inactivity were also associated with more frequent symptoms. It’s always a good idea to quit smoking and exercise. But there are no interventional trials on smoking cessation and menopausal symptoms to prove cause and effect, and randomized controlled trials of exercise failed to show any symptom relief. Of course, you could just take hormone therapy––but at the cost of significantly higher risk of suffering a heart attack, stroke, blood clot, breast cancer, or gallbladder disease. What can we do naturally to avoid the extra clots and cancer?
Hot flashes, also referred to as hot flushes, are the most common menopausal symptom for which women seek treatment. They afflict up to 80 to 85 percent of European and American women, lasting, along with night sweats, for an average of more than seven years. But these symptoms are not universal. Though in North America they may be considered inevitable, if you noticed, in Japan, for example, only 15 percent may be affected. In fact, there isn’t even a term for hot flash in the Japanese language.
The absence of even a word for it in Japan is all the more remarkable, because Japanese is said to be “infinitely more sensitive” than English in describing bodily states, with all sorts of extremely subtle distinctions for somatic sensations. For example, there are all sorts of specific terms describing different sensations. In Japanese there are 20 or more words just to describe the state of one’s stomach and intestines alone. But hot flashes appear to be so unusual there, researchers had to come up with ways to describe it in Japanese surveys. Investigators suspected it might be the soy.
Dietary surveys have estimated that soy isoflavone intake, the phytoestrogens in soy, is at least ten times higher than in Europe or North America. And one comparison of urine metabolites revealed Japanese women have a hundred times more phytoestrogens flowing through their body at any one time. To see if this might be playing a role, researchers followed a thousand Japanese women over time, starting before they reached menopause, to see if soy consumption was linked to whether or not they developed hot flashes. Women eating around four ounces of tofu a day only had half the risk compared to women only eating an ounce or two a day. The researchers concluded, “Our findings suggest that consumption of soy products is a practical strategy for preventing hot flashes.” But only if interventional trials prove they actually work––which I’ll cover next.
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- Freeman EW, Sherif K. Prevalence of hot flushes and night sweats around the world: a systematic review. Climacteric. 2007;10(3):197-214.
- Gold EB, Sternfeld B, Kelsey JL, et al. Relation of demographic and lifestyle factors to symptoms in a multi-racial/ethnic population of women 40-55 years of age. Am J Epidemiol. 2000;152(5):463-473.
- Liu B, Du Y, Wu Y, Snetselaar LG, Wallace RB, Bao W. Trends in obesity and adiposity measures by race or ethnicity among adults in the United States 2011-18: population based study. BMJ. 2021;372:n365.
- Huang AJ, Subak LL, Wing R, et al. An intensive behavioral weight loss intervention and hot flushes in women. Arch Intern Med. 2010;170(13):1161-1167.
- Goughnour SL, Thurston RC, Althouse AD, et al. Assessment of hot flushes and vaginal dryness among obese women undergoing bariatric surgery. Climacteric. 2016;19(1):71-76.
- Daley A, Stokes-Lampard H, Thomas A, MacArthur C. Exercise for vasomotor menopausal symptoms. Cochrane Database Syst Rev. 2014;(11):CD006108.
- Marjoribanks J, Farquhar CM, Roberts H, Lethaby A. Cochrane corner: long-term hormone therapy for perimenopausal and postmenopausal women. Heart. 2018;104(2):93-95.
- Messina M. Soy and health update: evaluation of the clinical and epidemiologic literature. Nutrients. 2016;8(12):754.
- Thomas AJ, Ismail R, Taylor-Swanson L, et al. Effects of isoflavones and amino acid therapies for hot flashes and co-occurring symptoms during the menopausal transition and early postmenopause: a systematic review. Maturitas. 2014;78(4):263-276.
- Avis NE, Crawford SL, Greendale G, et al. Duration of menopausal vasomotor symptoms over the menopause transition. JAMA Intern Med. 2015;175(4):531-539.
- Avis NE, Kaufert PA, Lock M, McKinlay SM, Vass K. The evolution of menopausal symptoms. Baillieres Clin Endocrinol Metab. 1993;7(1):17-32.
- Lock M. Contested meanings of the menopause. Lancet. 1991;337(8752):1270-1272.
- Lock M. Ambiguities of aging: Japanese experience and perceptions of menopause. Cult Med Psychiatry. 1986;10(1):23-46.
- Avis NE, Stellato R, Crawford S, et al. Is there a menopausal syndrome? Menopausal status and symptoms across racial/ethnic groups. Soc Sci Med. 2001;52(3):345-356.
- Gold EB, Block G, Crawford S, et al. Lifestyle and demographic factors in relation to vasomotor symptoms: baseline results from the Study of Women’s Health Across the Nation. Am J Epidemiol. 2004;159(12):1189-1199.
- Nagata C, Takatsuka N, Kawakami N, Shimizu H. Soy product intake and hot flashes in Japanese women: results from a community-based prospective study. Am J Epidemiol. 2001;153(8):790-793.
Motion graphics by Avo Media
Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
SWAN, which stands for Study of Women’s Health Across the Nation, is by far the largest evaluation of menopausal symptoms in history, studying 16,000 American women between the ages of 40 and 55. They found that women over a body mass index of 27 or higher were significantly more likely to suffer from hot flashes or night sweats, stiffness or soreness, and urinary leakage. A BMI over 25 is considered overweight; 30 is obese; and the average U.S. BMI is 29.8. Since fatty tissue is a source for estrogen, one might expect the reverse. But the link between excess body fat and worse menopausal symptoms indeed seems causal, since women randomized to a weight loss intervention experience significant improvement in hot flashes––an effect that may extend to bariatric surgery.
In the SWAN study, smoking and inactivity were also associated with more frequent symptoms. It’s always a good idea to quit smoking and exercise. But there are no interventional trials on smoking cessation and menopausal symptoms to prove cause and effect, and randomized controlled trials of exercise failed to show any symptom relief. Of course, you could just take hormone therapy––but at the cost of significantly higher risk of suffering a heart attack, stroke, blood clot, breast cancer, or gallbladder disease. What can we do naturally to avoid the extra clots and cancer?
Hot flashes, also referred to as hot flushes, are the most common menopausal symptom for which women seek treatment. They afflict up to 80 to 85 percent of European and American women, lasting, along with night sweats, for an average of more than seven years. But these symptoms are not universal. Though in North America they may be considered inevitable, if you noticed, in Japan, for example, only 15 percent may be affected. In fact, there isn’t even a term for hot flash in the Japanese language.
The absence of even a word for it in Japan is all the more remarkable, because Japanese is said to be “infinitely more sensitive” than English in describing bodily states, with all sorts of extremely subtle distinctions for somatic sensations. For example, there are all sorts of specific terms describing different sensations. In Japanese there are 20 or more words just to describe the state of one’s stomach and intestines alone. But hot flashes appear to be so unusual there, researchers had to come up with ways to describe it in Japanese surveys. Investigators suspected it might be the soy.
Dietary surveys have estimated that soy isoflavone intake, the phytoestrogens in soy, is at least ten times higher than in Europe or North America. And one comparison of urine metabolites revealed Japanese women have a hundred times more phytoestrogens flowing through their body at any one time. To see if this might be playing a role, researchers followed a thousand Japanese women over time, starting before they reached menopause, to see if soy consumption was linked to whether or not they developed hot flashes. Women eating around four ounces of tofu a day only had half the risk compared to women only eating an ounce or two a day. The researchers concluded, “Our findings suggest that consumption of soy products is a practical strategy for preventing hot flashes.” But only if interventional trials prove they actually work––which I’ll cover next.
Please consider volunteering to help out on the site.
- Freeman EW, Sherif K. Prevalence of hot flushes and night sweats around the world: a systematic review. Climacteric. 2007;10(3):197-214.
- Gold EB, Sternfeld B, Kelsey JL, et al. Relation of demographic and lifestyle factors to symptoms in a multi-racial/ethnic population of women 40-55 years of age. Am J Epidemiol. 2000;152(5):463-473.
- Liu B, Du Y, Wu Y, Snetselaar LG, Wallace RB, Bao W. Trends in obesity and adiposity measures by race or ethnicity among adults in the United States 2011-18: population based study. BMJ. 2021;372:n365.
- Huang AJ, Subak LL, Wing R, et al. An intensive behavioral weight loss intervention and hot flushes in women. Arch Intern Med. 2010;170(13):1161-1167.
- Goughnour SL, Thurston RC, Althouse AD, et al. Assessment of hot flushes and vaginal dryness among obese women undergoing bariatric surgery. Climacteric. 2016;19(1):71-76.
- Daley A, Stokes-Lampard H, Thomas A, MacArthur C. Exercise for vasomotor menopausal symptoms. Cochrane Database Syst Rev. 2014;(11):CD006108.
- Marjoribanks J, Farquhar CM, Roberts H, Lethaby A. Cochrane corner: long-term hormone therapy for perimenopausal and postmenopausal women. Heart. 2018;104(2):93-95.
- Messina M. Soy and health update: evaluation of the clinical and epidemiologic literature. Nutrients. 2016;8(12):754.
- Thomas AJ, Ismail R, Taylor-Swanson L, et al. Effects of isoflavones and amino acid therapies for hot flashes and co-occurring symptoms during the menopausal transition and early postmenopause: a systematic review. Maturitas. 2014;78(4):263-276.
- Avis NE, Crawford SL, Greendale G, et al. Duration of menopausal vasomotor symptoms over the menopause transition. JAMA Intern Med. 2015;175(4):531-539.
- Avis NE, Kaufert PA, Lock M, McKinlay SM, Vass K. The evolution of menopausal symptoms. Baillieres Clin Endocrinol Metab. 1993;7(1):17-32.
- Lock M. Contested meanings of the menopause. Lancet. 1991;337(8752):1270-1272.
- Lock M. Ambiguities of aging: Japanese experience and perceptions of menopause. Cult Med Psychiatry. 1986;10(1):23-46.
- Avis NE, Stellato R, Crawford S, et al. Is there a menopausal syndrome? Menopausal status and symptoms across racial/ethnic groups. Soc Sci Med. 2001;52(3):345-356.
- Gold EB, Block G, Crawford S, et al. Lifestyle and demographic factors in relation to vasomotor symptoms: baseline results from the Study of Women’s Health Across the Nation. Am J Epidemiol. 2004;159(12):1189-1199.
- Nagata C, Takatsuka N, Kawakami N, Shimizu H. Soy product intake and hot flashes in Japanese women: results from a community-based prospective study. Am J Epidemiol. 2001;153(8):790-793.
Motion graphics by Avo Media
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Menopausal Hot Flashes Are Not Inevitable
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Content URLDoctor's Note
I continue with this topic in the next video, Soy Foods for Menopause Hot Flash Symptoms. Also see Dietary Approach to Naturally Treating Menopause Symptoms.
I recently did a series on vaginal menopause symptoms, including:
- The Best Moisturizers and Lubricants for Vaginal Menopause Symptoms
- Hormone Treatment (Estrogen Pills and Creams) for Vaginal Menopause Symptoms
- Soy Milk for Vaginal Menopause Symptoms
For more on how to live your longest, healthiest life, preorder my new book How Not to Age. (As always, all proceeds I receive from all of my books are donated to charity.)
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