Certain gut bacteria can supercharge the benefits of soy foods, resulting in even more bone protection, better control of menopausal symptoms, and lower prostate cancer risk, but how can we foster the growth of these good bacteria?
How to Convert Into an Equol Producer
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.
“Menopause is characterized by a decrease in estrogen, which triggers the uncomfortable symptoms of hot flushes, night sweats, sleep disturbances, and vaginal dryness. Among these menopausal symptoms, hot flushes [also known as hot flashes] are reported by many women to be the most bothersome.” I already summarized the available evidence on the role of soy phytoestrogens to help alleviate those symptoms. Here’s the latest meta-analysis. Although the balance of evidence point to soy benefits, the individual study results are all over the place. Yes, some studies show 20, 30, even 40% better than control, but some showed no effect.
This is something that’s been noted by the professional societies, like the American College of OB/GYNs. Yes, these supplements may work, but the evidence is so inconsistent. This may be partly because the supplements used were extracted from different parts of the soybean. Maybe it would be better if they just used soy foods rather than supplements. The dosing would be about “two servings of traditional soyfoods” a day—like two cups of soy milk, which is what you see older women in Japan doing, who have some of the lowest reported rates of hot flashes in the world. But, even the studies on soy foods, as opposed to supplements, have had “conflicting results.” Why all the inconsistency? It may have to do with our gut bacteria.
People who eat foods made from soybeans, which have these “health-promoting isoflavones,” tend to have lower rates of a variety of chronic diseases. So, we can garner this protection by eating more soy foods, right? Well, it may be a little “more complicated” than that. There are certain gut bacteria that can convert isoflavones in soy into a potentially even more beneficial compound, called equol. Not all individuals can make this conversion, though, because not all individuals have the specific types of good bacteria in their gut that do it. So, there’s two types of people in the world: “equol producers” and “equol nonproducers”—depending on their gut flora. And so, this may help account for the variations in health benefits we see in clinical studies. It may help explain why some people seem to benefit from soy more than others.
For example, in the study I covered before, about how soy milk appears to prevent bone loss in the spines of postmenopausal women, if you split the women into equol producers and nonproducers, soy did work in non-equol producers, but seemed to work even better in the women whose gut bacteria is able to take the soy to the next level.
The more equol Japanese women make from the soy they eat, the fewer menopausal symptoms they may have. Some studies suggest equol-producing men may get less prostate cancer. If that’s the case, maybe we should look into improving the intestinal environment to enable equol production. Only a minority “of the Western adult population” is able to produce equol, though almost every other animal species appears to produce it; no problem.
In fact, that’s how it got its name. It’s named equol because it was first discovered in horses. But, interestingly, horses during the summer, not winter—because that’s when their gut bacteria had access to the phytoestrogens in clover. That was our first clue equol was made from plants. If you’re not Mr. Ed, though, “can [you] take someone who [doesn’t] make equol and convert them [in]to an equol-producer? Certainly, [you can] do the reverse; excessive use of antibiotics” can wipe out your good bugs. But how can you acquire the right good bugs? Suggested strategies include dietary alteration or probiotics.
The standard probiotic regimens don’t seem to help; so, how about dietary alteration? Well, about half of Japanese and Korean individuals can produce equol, but only as low as one in seven Americans. Maybe it’s because more soy is eaten in Asia? I mean, that would make sense—if you eat a lot of soy, you may foster the growth of bacteria in your gut that can digest soy. But, a month of soy isoflavone supplement exposure didn’t seem to convert nonproducers into producers. But, just two weeks of drinking three glasses of soy milk a day was able to convert three of six women into producers. For example, this woman started out not making any at all, or maybe a little bump between hours 50 and 60, but after two weeks of drinking soy milk, when they had her drink some more, she had nice equol spikes.
It didn’t work for all women, though. And, when they tried the same experiment in men, nothing happened. Hmm, back to the drawing board. Is there any group of Westerners that have high equol production rates that may offer a clue? Vegetarians have among the highest equol production rates ever recorded—more than four times as “likely to be…equol producers as their nonvegetarian counterparts.” The question is, why? They don’t think it’s because of the soy, given the conflicting soy data. Maybe it’s because they’re eating more prebiotics, like fiber?
Or, maybe “dietary fat intake decreases the capacity of gut…flora to [make] equol.” Or, maybe it has something to do with cholesterol intake? Analyzing the diets of equol producers, they do seem more likely to be eating more carbs, plant protein, and fiber. But, researchers have tried giving people fiber supplements along with soy, but that didn’t seem to work. Whatever it is about those eating plant-based diets, they may soon be the only remaining majority equol producers, as Asian populations continue to Westernize their diets.
Please consider volunteering to help out on the site.
- Akaza H, Miyanaga N, Takashima N, Naito S, Hirao Y, Tsukamoto T, Fujioka T, Mori M, Kim WJ, Song JM, Pantuck AJ. Comparisons of percent equol producers between prostate cancer patients and controls: case-controlled studies of isoflavones in Japanese, Korean and American residents. Jpn J Clin Oncol. 2004 Feb;34(2):86-9.
- Lu LJ, Lin SN, Grady JJ, Nagamani M, Anderson KE. Altered kinetics and extent of urinary daidzein and genistein excretion in women during chronic soya exposure. Nutr Cancer. 1996;26(3):289-302.
- Yuan JP, Wang JH, Liu X. Metabolism of dietary soy isoflavones to equol by human intestinal microflora--implications for health. Mol Nutr Food Res. 2007 Jul;51(7):765-81.
- Chen MN, Lin CC, Liu CF. Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and systematic review. Climacteric. 2015 Apr;18(2):260-9.
- Messina M. Soybean isoflavones warrant greater consideration as a treatment for the alleviation of menopausal hot flashes. Womens Health (Lond). 2014 Nov;10(6):549-53.
- Setchell KD, Cole SJ. Method of defining equol-producer status and its frequency among vegetarians. J Nutr. 2006 Aug;136(8):2188-93.
- Védrine N, Mathey J, Morand C, Brandolini M, Davicco MJ, Guy L, Rémésy C, Coxam V, Manach C. One-month exposure to soy isoflavones did not induce the ability to produce equol in postmenopausal women. Eur J Clin Nutr. 2006 Sep;60(9):1039-45.
- Setchell KD, Brown NM, Summer S, King EC, Heubi JE, Cole S, Guy T, Hokin B. Dietary factors influence production of the soy isoflavone metabolite s-(-)equol in healthy adults. J Nutr. 2013 Dec;143(12):1950-8.
- Setchell KD, Brown NM, Lydeking-Olsen E. The clinical importance of the metabolite equol-a clue to the effectiveness of soy and its isoflavones. J Nutr. 2002 Dec;132(12):3577-84.
- Freeman EW, Sherif K. Prevalence of hot flushes and night sweats around the world: a systematic review. Climacteric. 2007 Jun;10(3):197-214.
- Kurzer MS. Soy consumption for reduction of menopausal symptoms. Inflammopharmacology. 2008 Oct;16(5):227-9.
- Levis S, Griebeler ML. The role of soy foods in the treatment of menopausal symptoms. J Nutr. 2010 Dec;140(12):2318S-2321S.
- Akaza H. Prostate cancer chemoprevention by soy isoflavones: role of intestinal bacteria as the "second human genome". Cancer Sci. 2012 Jun;103(6):969-75.
- Sugiyama Y, Masumori N, Fukuta F, Yoneta A, Hida T, Yamashita T, Minatoya M, Nagata Y, Mori M, Tsuji H, Akaza H, Tsukamoto T. Influence of isoflavone intake and equol-producing intestinal flora on prostate cancer risk. Asian Pac J Cancer Prev. 2013;14(1):1-4.
- Lampe JW, Skor HE, Li S, Wähälä K, Howald WN, Chen C. Wheat bran and soy protein feeding do not alter urinary excretion of the isoflavan equol in premenopausal women. J Nutr. 2001 Mar;131(3):740-4.
- Aso T. Equol improves menopausal symptoms in Japanese women. J Nutr. 2010 Jul;140(7):1386S-9S.
- Bonorden MJ, Greany KA, Wangen KE, Phipps WR, Feirtag J, Adlercreutz H, Kurzer MS. Consumption of Lactobacillus acidophilus and Bifidobacterium longum do not alter urinary equol excretion and plasma reproductive hormones in premenopausal women. Eur J Clin Nutr. 2004 Dec;58(12):1635-42.
- 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.
- Lampe JW, Karr SC, Hutchins AM, Slavin JL. Urinary equol excretion with a soy challenge: influence of habitual diet. Proc Soc Exp Biol Med. 1998 Mar;217(3):335-9.
- Lydeking-Olsen E, Beck-Jensen JE, Setchell KD, Holm-Jensen T. Soymilk or progesterone for prevention of bone loss--a 2 year randomized, placebo-controlled trial. Eur J Nutr. 2004 Aug;43(4):246-57.
Icons created by Vladimir Belochkin, Ben Davis, and Ross Butcher from The Noun Project.
Image credit: Devanath via Pixabay. Image has been modified.
Motion graphics by Avocado Video
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.
“Menopause is characterized by a decrease in estrogen, which triggers the uncomfortable symptoms of hot flushes, night sweats, sleep disturbances, and vaginal dryness. Among these menopausal symptoms, hot flushes [also known as hot flashes] are reported by many women to be the most bothersome.” I already summarized the available evidence on the role of soy phytoestrogens to help alleviate those symptoms. Here’s the latest meta-analysis. Although the balance of evidence point to soy benefits, the individual study results are all over the place. Yes, some studies show 20, 30, even 40% better than control, but some showed no effect.
This is something that’s been noted by the professional societies, like the American College of OB/GYNs. Yes, these supplements may work, but the evidence is so inconsistent. This may be partly because the supplements used were extracted from different parts of the soybean. Maybe it would be better if they just used soy foods rather than supplements. The dosing would be about “two servings of traditional soyfoods” a day—like two cups of soy milk, which is what you see older women in Japan doing, who have some of the lowest reported rates of hot flashes in the world. But, even the studies on soy foods, as opposed to supplements, have had “conflicting results.” Why all the inconsistency? It may have to do with our gut bacteria.
People who eat foods made from soybeans, which have these “health-promoting isoflavones,” tend to have lower rates of a variety of chronic diseases. So, we can garner this protection by eating more soy foods, right? Well, it may be a little “more complicated” than that. There are certain gut bacteria that can convert isoflavones in soy into a potentially even more beneficial compound, called equol. Not all individuals can make this conversion, though, because not all individuals have the specific types of good bacteria in their gut that do it. So, there’s two types of people in the world: “equol producers” and “equol nonproducers”—depending on their gut flora. And so, this may help account for the variations in health benefits we see in clinical studies. It may help explain why some people seem to benefit from soy more than others.
For example, in the study I covered before, about how soy milk appears to prevent bone loss in the spines of postmenopausal women, if you split the women into equol producers and nonproducers, soy did work in non-equol producers, but seemed to work even better in the women whose gut bacteria is able to take the soy to the next level.
The more equol Japanese women make from the soy they eat, the fewer menopausal symptoms they may have. Some studies suggest equol-producing men may get less prostate cancer. If that’s the case, maybe we should look into improving the intestinal environment to enable equol production. Only a minority “of the Western adult population” is able to produce equol, though almost every other animal species appears to produce it; no problem.
In fact, that’s how it got its name. It’s named equol because it was first discovered in horses. But, interestingly, horses during the summer, not winter—because that’s when their gut bacteria had access to the phytoestrogens in clover. That was our first clue equol was made from plants. If you’re not Mr. Ed, though, “can [you] take someone who [doesn’t] make equol and convert them [in]to an equol-producer? Certainly, [you can] do the reverse; excessive use of antibiotics” can wipe out your good bugs. But how can you acquire the right good bugs? Suggested strategies include dietary alteration or probiotics.
The standard probiotic regimens don’t seem to help; so, how about dietary alteration? Well, about half of Japanese and Korean individuals can produce equol, but only as low as one in seven Americans. Maybe it’s because more soy is eaten in Asia? I mean, that would make sense—if you eat a lot of soy, you may foster the growth of bacteria in your gut that can digest soy. But, a month of soy isoflavone supplement exposure didn’t seem to convert nonproducers into producers. But, just two weeks of drinking three glasses of soy milk a day was able to convert three of six women into producers. For example, this woman started out not making any at all, or maybe a little bump between hours 50 and 60, but after two weeks of drinking soy milk, when they had her drink some more, she had nice equol spikes.
It didn’t work for all women, though. And, when they tried the same experiment in men, nothing happened. Hmm, back to the drawing board. Is there any group of Westerners that have high equol production rates that may offer a clue? Vegetarians have among the highest equol production rates ever recorded—more than four times as “likely to be…equol producers as their nonvegetarian counterparts.” The question is, why? They don’t think it’s because of the soy, given the conflicting soy data. Maybe it’s because they’re eating more prebiotics, like fiber?
Or, maybe “dietary fat intake decreases the capacity of gut…flora to [make] equol.” Or, maybe it has something to do with cholesterol intake? Analyzing the diets of equol producers, they do seem more likely to be eating more carbs, plant protein, and fiber. But, researchers have tried giving people fiber supplements along with soy, but that didn’t seem to work. Whatever it is about those eating plant-based diets, they may soon be the only remaining majority equol producers, as Asian populations continue to Westernize their diets.
Please consider volunteering to help out on the site.
- Akaza H, Miyanaga N, Takashima N, Naito S, Hirao Y, Tsukamoto T, Fujioka T, Mori M, Kim WJ, Song JM, Pantuck AJ. Comparisons of percent equol producers between prostate cancer patients and controls: case-controlled studies of isoflavones in Japanese, Korean and American residents. Jpn J Clin Oncol. 2004 Feb;34(2):86-9.
- Lu LJ, Lin SN, Grady JJ, Nagamani M, Anderson KE. Altered kinetics and extent of urinary daidzein and genistein excretion in women during chronic soya exposure. Nutr Cancer. 1996;26(3):289-302.
- Yuan JP, Wang JH, Liu X. Metabolism of dietary soy isoflavones to equol by human intestinal microflora--implications for health. Mol Nutr Food Res. 2007 Jul;51(7):765-81.
- Chen MN, Lin CC, Liu CF. Efficacy of phytoestrogens for menopausal symptoms: a meta-analysis and systematic review. Climacteric. 2015 Apr;18(2):260-9.
- Messina M. Soybean isoflavones warrant greater consideration as a treatment for the alleviation of menopausal hot flashes. Womens Health (Lond). 2014 Nov;10(6):549-53.
- Setchell KD, Cole SJ. Method of defining equol-producer status and its frequency among vegetarians. J Nutr. 2006 Aug;136(8):2188-93.
- Védrine N, Mathey J, Morand C, Brandolini M, Davicco MJ, Guy L, Rémésy C, Coxam V, Manach C. One-month exposure to soy isoflavones did not induce the ability to produce equol in postmenopausal women. Eur J Clin Nutr. 2006 Sep;60(9):1039-45.
- Setchell KD, Brown NM, Summer S, King EC, Heubi JE, Cole S, Guy T, Hokin B. Dietary factors influence production of the soy isoflavone metabolite s-(-)equol in healthy adults. J Nutr. 2013 Dec;143(12):1950-8.
- Setchell KD, Brown NM, Lydeking-Olsen E. The clinical importance of the metabolite equol-a clue to the effectiveness of soy and its isoflavones. J Nutr. 2002 Dec;132(12):3577-84.
- Freeman EW, Sherif K. Prevalence of hot flushes and night sweats around the world: a systematic review. Climacteric. 2007 Jun;10(3):197-214.
- Kurzer MS. Soy consumption for reduction of menopausal symptoms. Inflammopharmacology. 2008 Oct;16(5):227-9.
- Levis S, Griebeler ML. The role of soy foods in the treatment of menopausal symptoms. J Nutr. 2010 Dec;140(12):2318S-2321S.
- Akaza H. Prostate cancer chemoprevention by soy isoflavones: role of intestinal bacteria as the "second human genome". Cancer Sci. 2012 Jun;103(6):969-75.
- Sugiyama Y, Masumori N, Fukuta F, Yoneta A, Hida T, Yamashita T, Minatoya M, Nagata Y, Mori M, Tsuji H, Akaza H, Tsukamoto T. Influence of isoflavone intake and equol-producing intestinal flora on prostate cancer risk. Asian Pac J Cancer Prev. 2013;14(1):1-4.
- Lampe JW, Skor HE, Li S, Wähälä K, Howald WN, Chen C. Wheat bran and soy protein feeding do not alter urinary excretion of the isoflavan equol in premenopausal women. J Nutr. 2001 Mar;131(3):740-4.
- Aso T. Equol improves menopausal symptoms in Japanese women. J Nutr. 2010 Jul;140(7):1386S-9S.
- Bonorden MJ, Greany KA, Wangen KE, Phipps WR, Feirtag J, Adlercreutz H, Kurzer MS. Consumption of Lactobacillus acidophilus and Bifidobacterium longum do not alter urinary equol excretion and plasma reproductive hormones in premenopausal women. Eur J Clin Nutr. 2004 Dec;58(12):1635-42.
- 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.
- Lampe JW, Karr SC, Hutchins AM, Slavin JL. Urinary equol excretion with a soy challenge: influence of habitual diet. Proc Soc Exp Biol Med. 1998 Mar;217(3):335-9.
- Lydeking-Olsen E, Beck-Jensen JE, Setchell KD, Holm-Jensen T. Soymilk or progesterone for prevention of bone loss--a 2 year randomized, placebo-controlled trial. Eur J Nutr. 2004 Aug;43(4):246-57.
Icons created by Vladimir Belochkin, Ben Davis, and Ross Butcher from The Noun Project.
Image credit: Devanath via Pixabay. Image has been modified.
Motion graphics by Avocado Video
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How to Convert Into an Equol Producer
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Content URLDoctor's Note
What was that about safely helping to control hot flashes? Check out my video Soy Phytoestrogens for Menopause Hot Flashes.
Plant-based eating has a variety of healthy effects on our good gut bacteria. See, for example:
- Microbiome: The Inside Story
- Prebiotics: Tending Our Inner Garden
- What’s Your Gut Microbiome Enterotype?
- How to Change Your Enterotype
- How to Develop a Healthy Gut Ecosystem
- How to Become a Fecal Transplant Super Donor
- How to Reduce Your TMAO Levels
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