Soy Foods: Studies & Doctors Report Great Health Benefits & Debunk Myths.
Page Menu – to jump to sections below regards:
1. Reports from Science Journals about the Health Benefits of Consuming Soy
– Regards Soy & Male Hormones
– Regards Soy Versus Breast Cancer
– Regards Soy versus Prostate Cancer
– Regards Other Health Benefits Associated with Soy Consumption
– Regards Soy & Thyroid Health
1. Reports from Science Journals about the Health Benefits of Consuming Soy:
A 2010 report in The Journal of Nutrition is titled “Insights gained from 20 years of soy research.” Summary: “over the past 20 y an impressive amount of soy-related research has evaluated the role of these foods in REDUCING CHRONIC DISEASE RISK…
There is intriguing animal and epidemiologic evidence indicating that modest amounts of soy consumed during childhood and/or adolescence REDUCES BREAST CANCER RISK.
EVIDENCE ALSO SUGGESTS THAT SOY REDUCES PROSTATE CANCER RISK and inhibits prostate tumor metastasis…
there is suggestive epidemiologic evidence that soyfoods LOWER RISK OF CORONARY HEART DISEASE (CHD) independent of effects on cholesterol.
In clinical studies, soy favorably affects multiple CHD risk factors…
In regard to bone health… 2 large prospective epidemiologic studies found SOY INTAKE IS ASSOCIATED WITH MARKED REDUCTIONS IN FRACTURE RISK.
Soybean isoflavones also modestly alleviate hot flashes in menopausal women.
Finally, other than allergic reactions, there is almost NO CREDIBLE EVIDENCE to suggest traditional soyfoods exert clinically relevant adverse effects in healthy individuals when consumed in amounts consistent with Asian intake.”
Reference: “Insights gained from 20 years of soy research”, J Nutr., 2010 Dec; 140(12):2289S-2295S at https://www.ncbi.nlm.nih.gov/pubmed/20980639
According to the MedlinePlus website, care of the U.S. National Library of Medicine: “Soy in your diet can lower cholesterol. Many research studies support this claim. The U.S. Food and Drug Administration (FDA) agrees that 25 grams per day of soy protein may reduce the risk of heart disease. Health benefits of soy products may be due to their high levels of polyunsaturated fats, fiber, minerals, vitamins, and low saturated fat content.
Isoflavones that occur naturally in soy product may play a part in preventing some hormone-related cancers. Eating a diet that has a moderate amount of soy prior to adulthood may lower the risk of breast and ovarian cancer in women …
Whole soy in products like tofu, soy milk and edamame is preferable to processed soy such as the soy protein isolates that are found in many snack products.”
Dr Michael Greger’s 2016 youtube clip titled “Who Shouldn’t Eat Soy?” introduction: “How can soy foods have it both ways, pro-estrogenic effects in some organs (protecting bones and reducing hot flash symptoms) but anti-estrogenic effects in others (protecting against breast and endometrial cancer)?” is at https://www.youtube.com/watch?v=vltbg3NUSQs
Some excerpts: “Women who ate the most soy had 30% less endometrial cancer, and appeared to cut their ovarian cancer risk nearly in half…
In terms of bone health… The study clearly shows that the soy phytoestrogen prevents bone loss, and enhances new bone formation, in turn producing a net gain of bone mass… A significantly lower risk of bone fracture associated with just a single serving of soy a day — the equivalent of 5 to 7 grams of soy protein, or 20 to 30 milligrams of phytoestrogens. So, that’s just like one cup of soy milk — or, even better, a serving of a whole soy food, like tempeh or edamame, or the beans themselves…
Is there anyone who should avoid soy? Well, some people have soy allergies. A national survey found that only about 1 in 2,000 people report a soy allergy. That’s 40 times less than the most common allergen—dairy milk—and about ten times less than all the other common allergens—like fish, eggs, shellfish, nuts, wheat, or peanuts.”
The text transcript is at https://nutritionfacts.org/video/who-shouldnt-eat-soy/
A 2009 article in the peer-reviewed medical journal American Family Physician is titled “Soy: a complete source of protein“. The abstract states: “Soybeans contain all of the essential amino acids necessary for human nutrition and have been grown and harvested for thousands of years. Populations with diets high in soy protein and low in animal protein have lower risks of prostate and breast cancers than other populations. Increasing dietary whole soy protein lowers levels of total cholesterol, low-density lipoproteins, and triglycerides; may improve menopausal hot flashes; and may help maintain bone density and decrease fractures in postmenopausal women. There are not enough data to make recommendations concerning soy intake in women with a history of breast cancer. The refined soy isoflavone components, when given as supplements, have not yielded the same results as increasing dietary whole soy protein. Overall, soy is well tolerated, and because it is a complete source of protein shown to lower cholesterol, it is recommended as a dietary substitution for higher-fat animal products.”
Reference: “Soy: a complete source of protein”, Am Fam Physician, 2009 Jan 1;79(1):43-7; https://www.ncbi.nlm.nih.gov/pubmed/19145965/
“American Family Physician is a biweekly peer-reviewed medical journal published by the American Academy of Family Physicians” https://en.wikipedia.org/wiki/American_Family_Physician
From an article in Permanente Journal co-authored by several medical doctors: “Soybeans and foods made from soybeans are good sources of protein and may help lower levels of low-density lipoprotein in the blood and reduce the risk of hip fractures and some cancers…
A study in the Journal of the American Medical Association reported that women with breast cancer who regularly consumed soy products had a 32% lower risk of breast cancer recurrence and a 29% decreased risk of death, compared with women who consumed little or no soy. An analysis of 14 studies, published in the American Journal of Clinical Nutrition, showed that increased intake of soy resulted in a 26% reduction in prostate cancer risk.
Because of concerns over the estrogenic nature of soy products, women with a history of breast cancer should discuss soy foods with their oncologists. Also, overly processed, soy-based meat substitutes are often high in isolated soy proteins and other ingredients that may not be as healthy as less processed soy products (ie, tofu, tempeh, and soy milk)…”
Reference: “Nutritional Update for Physicians: Plant-Based Diets”, Perm J. 2013 Spring; 17(2): 61–66. doi: 10.7812/TPP/12-085; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3662288/
From a 2016 report in the science journal ‘Nutrients‘ – “Soyfoods have long been recognized as sources of high-quality protein and healthful fat, but over the past 25 years these foods have been rigorously investigated for their role in chronic disease prevention and treatment.
There is evidence, for example, that they reduce risk of coronary heart disease and breast and prostate cancer. In addition, soy alleviates hot flashes and may favorably affect renal function, alleviate depressive symptoms and improve skin health…
Despite the many proposed benefits, the presence of isoflavones has led to concerns that soy may exert untoward effects in some individuals. However, these concerns are based primarily on animal studies, whereas the human research supports the safety and benefits of soyfoods.
In support of safety is the recent conclusion of the European Food Safety Authority that isoflavones do NOT adversely affect the breast, thyroid or uterus of postmenopausal women.
This review covers each of the major research areas involving soy focusing primarily on the clinical and epidemiologic research…” (emphasis added)
Reference: “Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature”, Nutrients, 2016 Dec; 8(12): 754; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5188409/
The British Dietetic Association (BDA) has put together this factsheet regards the health benefits of soya and dispelling the negative scare stories about it – see: https://www.bda.uk.com/foodfacts/soya_and_health.pdf
The BDA “is the only body in the UK representing the whole of the dietetic workforce”.
Regards Soy & Male Hormones:
Regards Soy & Male Hormones this 2010 report in the science journal ‘Fertility & Sterility’concluded: “The results of this meta-analysis suggest that neither soy foods nor isoflavone supplements alter measures of bioavailable T[estosterone] concentrations in men.”
Reference: “Clinical studies show no effects of soy protein or isoflavones on reproductive hormones in men: results of a meta-analysis”, Fertility & Sterility, 2010, Aug;94(3): 997-1007; at https://www.ncbi.nlm.nih.gov/pubmed/19524224
Regards Male Hormones & Soy Consumption another 2010 report in the science journal ‘Fertility & Sterility’ reports: “findings from a recently published metaanalysis and subsequently published studies show that neither isoflavone supplements nor isoflavone-rich soy affect total or free testosterone (T) levels. Similarly, there is essentially no evidence from the nine identified clinical studies that isoflavone exposure affects circulating estrogen levels in men. Clinical evidence also indicates that isoflavones have no effect on sperm or semen parameters, although only three intervention studies were identified and none were longer than 3 months in duration. Finally, findings from animal studies… are not applicable to men, because of differences in isoflavone metabolism between rodents and humans and the excessively high amount of isoflavones to which the animals were exposed.
CONCLUSION(S): The intervention data indicate that isoflavones do not exert feminizing effects on men at intake levels equal to and even considerably higher than are typical for Asian males.”
Reference: “Soybean isoflavone exposure does not have feminizing effects on men: a critical examination of the clinical evidence”, Fertility and Sterility, 2010 May 1;93(7):2095-104; at https://www.ncbi.nlm.nih.gov/pubmed/20378106 and at http://www.fertstert.org/article/S0015-0282(10)00368-7/fulltext
In contrast, regards the lowering of testosterone levels due to “the effect of animal protein on stress hormones…” see this clip by Dr Michael Greger at https://www.youtube.com/watch?v=kXty_-3o7X8
Excerpts: “High-protein diets suppress testosterone. That’s why if you take men eating plant-based diets, and have them start eating meat every day, their testosterone levels go down, and actually some estrogens go up.
That’s why bodybuilders can get such low testosterone levels. It’s not the steroids they’re taking. If you look at natural bodybuilders, who don’t use steroids, 75% drop in testosterone levels in the months leading up to a competition. Testosterone levels cut by more than half; enough to drop a guy into an abnormally low range. It’s ironic that they’re eating protein to look manly on the outside, but it makes them less and less manly on the inside. And, from an obesity standpoint, in general, a drop in testosterone levels may increase the risk of gaining weight – gaining body fat…”
Text transcript at: https://nutritionfacts.org/video/the-effect-of-animal-protein-on-stress-hormones-testosterone-and-pregnancy/
Click the following links for many more science and news reports on:
i) the increasing rates of infertility in men and women associated with the hormone-disrupting consumption of meat and dairy as well as
ii) articles on the health advantages and benefits of consuming proteins from plants instead of from animals.
Regards Soy Versus Breast Cancer:
From the journal of the American Cancer Society: “Soy consumption is associated with decreased incidence of many cancers, including breast cancer … The totality of the evidence suggests that increased soy food consumption decreases the risk of breast cancer and results in better treatment outcomes in both Western and Asian women.”
Reference: “Soy foods, isoflavones, and breast cancer”, Cancer, Volume 123, Issue 11, June 1, 2017, Pages 1901-1903; https://onlinelibrary.wiley.com/doi/full/10.1002/cncr.30614
Short clip by Dr Michael Greger MD – “Is Soy Healthy for Breast Cancer Survivors?” at https://www.youtube.com/watch?v=6yeZ-rRJz0A
Summary – He highlights medical studies on soy consumption and breast cancer survival and comments: “they all point in the same direction, 5 out of 5 [studies], tracking more than 10,000 breast cancer patients. Pooling all the results, soy food intake after breast cancer diagnosis was associated with reduced mortality – meaning a longer lifespan – and reduced recurrence, so less likely the cancer comes back. Anyone who says otherwise hasn’t cracked a [medical] journal open in seven years…
So where did this outdated notion that soy could increase breast cancer risk come from? The concern was based largely on research… in a type of mouse. But it turns out we’re not actually mice. We metabolize soy isoflavones very differently from rodents…”
Text and sources at: https://nutritionfacts.org/video/is-soy-healthy-for-breast-cancer-survivors/
Regards Soy & Higher Survival Rates of Women with Breast Cancer – The journal of the American Cancer Society: “A 21% decrease was observed in all-cause mortality for women who had the highest versus lowest quartile of dietary [soy] isoflavone intake… In this large, ethnically diverse cohort of women with breast cancer living in North America, a higher dietary intake of isoflavone was associated with REDUCED all-cause mortality…” as “examined in 6235 women with breast cancer enrolled in the Breast Cancer Family Registry…”
Reference: “Dietary isoflavone intake and all-cause mortality in breast cancer survivors: The Breast Cancer Family Registry”, Cancer, Volume 123, Issue 11 June 1, 2017 Pages 2070–2079; https://www.ncbi.nlm.nih.gov/pubmed/28263368 and http://onlinelibrary.wiley.com/doi/10.1002/cncr.30615/abstract
A study reported in the Nutrients science journal in 2016 declared: “Higher total red meat, fresh red meat, and processed meat intake may be risk factors for breast cancer, whereas higher soy food… may reduce the risk of breast cancer.”
Reference: “Dietary Protein Sources and Incidence of Breast Cancer: A Dose-Response Meta-Analysis of Prospective Studies”, Nutrients, 2016 Nov 17;8(11); at https://www.ncbi.nlm.nih.gov/pubmed/27869663
Regards Soy versus Breast Cancer a 2013 report in the PLoS One science journal concluded: “Soy consumption may be associated with reduced risk of breast cancer incidence, recurrence, and mortality. Soy does not have estrogenic effects in humans...”
More specifically that: “Soy intake consistent with that of a traditional Japanese diet (2-3 servings daily, containing 25-50mg isoflavones) may be protective against breast cancer and recurrence. Human trials show that soy does not increase circulating estradiol or affect estrogen-responsive target tissues.”
About the report: “Of 4179 records, we included a total of 131 articles: 40 RCTs, 11 uncontrolled trials, and 80 observational studies.”
Reference: “Soy, red clover, and isoflavones and breast cancer: a systematic review”, PLoS One. 2013 Nov 28;8(11):e81968; at https://www.ncbi.nlm.nih.gov/pubmed/24312387
Regards Soy versus Breast Cancer a 2006 report in the Journal of Nutritional Science and Vitaminology concludes: “This meta-analysis supported the hypotheses that soyfood intake may be associated with a decreased risk of breast cancer due to the isoflavones. ”
Their specific findings: “The pooled RR of breast cancer for soyfood intake was 0.75 with a 95% CI of 0.59-0.95. As the main types of soyfood in Japan and China, tofu and miso showed clear protective effects. Isoflavone intake resulted in a 20% decrease in risk (RR = 0.81, 95% CI 0.67-0.99)…”
Reference: “Soyfood intake in the prevention of breast cancer risk in women: a meta-analysis of observational epidemiological studies”, J Nutr Sci Vitaminol (Tokyo). 2006 Dec;52(6):428-36; at https://www.ncbi.nlm.nih.gov/pubmed/17330506
Dr Greger clip “Should Women at High Risk for Breast Cancer Avoid Soy?” at https://www.youtube.com/watch?v=PWwCgATx-kU
Excerpt: “Five studies have been performed on breast cancer survival and soy foods, involving more than 10,000 breast cancer patients. And, those who eat more soy live longer, and have a lower risk of the cancer coming back…
in vitro, soy phytoestrogens could turn back on BRCA protection suppressed by breast cancer, upregulating BRCA expression as much as 1,000% within 48 hours. But, does that translate out of the petri dish and into the person? Apparently so.
Soy intake was only associated with 27% breast cancer risk reduction in people with normal BRCA genes, but a 73% risk reduction in carriers of BRCA gene mutations. So, a healthy diet may be particularly important in those at high genetic risk. Meat consumption, for example, was linked to twice as much risk in those with BRCA mutations—97% increased risk, instead of just 41% increased risk of breast cancer in those with normal BRCA genes…”
Text at https://nutritionfacts.org/video/should-women-at-high-risk-for-breast-cancer-avoid-soy/
Regards the lower rates of Breast Cancer and Soy Consumption the Cancer Science journal reported in 2010: “We observed a statistically significant inverse association between soy isoflavone and soy protein intake with breast cancer risk. The multivariate ORs (95% CIs) of breast cancer risk for the highest quartile compared with the lowest quartile were 0.54 (0.34-0.84) for soy isoflavone and 0.62 (0.40-0.96) for soy protein, respectively. A preventive effect of soy food was found for all subtypes of ER [estrogen receptor] and/or [progesterone receptor ] PR status of breast cancer…”
Reference: “Soy product and isoflavone intake and breast cancer risk defined by hormone receptor status”, Cancer Science, 2010 Feb;101(2):501-7; at https://www.ncbi.nlm.nih.gov/pubmed/19860847
Regards Breast Cancer prevention a 2017 report in Nutrition Reviews states: “Soyfoods have been intensely researched, primarily because they provide such abundant amounts of isoflavones … evidence suggests that soy does not exert adverse hormonal effects in children or affect pubertal development … there is intriguing evidence indicating that when soy is consumed during childhood and/or adolescence, risk of developing breast cancer is markedly reduced. Relatively few children are allergic to soy protein, and most of those who initially are outgrow their soy allergy by 10 years of age. The totality of the available evidence indicates that soyfoods can be healthful additions to the diets of children, but more research is required to allow definitive conclusions to be made.”
Reference: “Health impact of childhood and adolescent soy consumption,” Nutrition Reviews, 2017 Jul 1;75(7):500-515; at https://www.ncbi.nlm.nih.gov/pubmed/28838083
Regards Soy Versus Breast Cancer a 2008 report in the British Journal of Cancer concludes: “the evidence to date, based largely on case-control studies, suggest that soy food intake in the amount consumed in Asian populations may have protective effects against breast cancer.”
Their “Meta-analysis of the 8 (1 cohort, 7 case-control) studies conducted in high-soy-consuming Asians show a significant trend of decreasing risk with increasing soy food intake.”
The study found that “Compared to the lowest level of soy food intake (<or=5 mg isoflavones per day)” the odds ratios of developing breast cancer were just:
– 0.71 “among those with high intake (>or=20 mg isoflavones per day)”
– 0.88 “among those with modest (approximately 10 mg isoflavones per day)”
The report found “soy intake was unrelated to breast cancer risk in studies conducted in the 11 low-soy-consuming Western populations whose average highest and lowest soy isoflavone intake levels were around 0.8 and 0.15 mg per day, respectively.” Note how small those Western intakes are compared to the Asian intakes listed above.
Reference: “Epidemiology of soy exposures and breast cancer risk”, British Journal of Cancer, 2008 Jan 15;98(1):9-14; at https://www.ncbi.nlm.nih.gov/pubmed/18182974
Dr Greger MD clip “BRCA Breast Cancer Genes & Soy” at https://www.youtube.com/watch?v=ZCFxoUKOJYU
Summary: “One reason why soy consumption is associated with improved survival and lower recurrence rates in breast cancer patients may be because soy phytonutrients appear to improve the expression of tumor-suppressing BRCA genes.”
Excerpt: “we know that breast cancer survivors who eat soy foods, for example, have a significantly lower likelihood of the cancer recurrence… This 2012 review looked at three prospective human studies done to date, and found that women who ate the most soy had a 29% lower risk of dying from breast cancer, and a 36% lower risk of cancer recurrence. And, a fourth study was since published, and it showed the same thing. “[S]oy food intake is associated with longer survival and lower recurrence among breast cancer patients. With an average intake of soy phytonutrients above 17 milligrams a day, which is about what’s found in a single cup of soy milk, the mortality of breast cancer may be able to be reduced by as much as 38%…
only about 5% of breast cancers run in families. So, 95% of breast cancer victims have fully functional BRCA genes. So, if their DNA-repair mechanisms are intact, how did breast cancer form, grow, and spread? Well, tumors do it by suppressing the expression of the gene, through a process called methylation. The gene’s fine, but cancer found a way to turn it off, or at least turn it down—potentially facilitating the metastatic spread of the tumor.
And, that’s where soy may come in. Maybe the reason soy intake is associated with increased survival and decreased cancer recurrence is because the phytonutrients in soy turn back on your BRCA protection—removing the methyl straightjacket the tumor tried to place on it.”
Text at https://nutritionfacts.org/video/brca-breast-cancer-genes-and-soy/
A study on Soy versus Breast Cancer, as reported in the Journal of the American Medical Association, concluded: “Among women with breast cancer, soy food consumption was significantly associated with decreased risk of death and recurrence.”
It was “a large, population-based cohort study of 5,042 female breast cancer survivors” with “median follow-up of 3.9 years”. Also known as the “Shanghai Breast Cancer Survival Study.”
Specific findings include: “Soy food intake, as measured either by soy protein or soy isoflavone intake, was inversely associated [meaning lower rates] with mortality and recurrence. The hazard ratio (HR) associated with highest quartile of soy protein intake was 0.67… for total mortality and 0.66… for recurrence compared with the lowest quartile of intake.”
In other words people in the highest quarter of soy consumption had 33% lower rates of dying – total mortality – and 34% lower rates of recurrence of breast cancer.
Additionally, “The multivariate adjusted 5-year mortality rates” were:
– 13.1% for women in the lowest quartile of soy protein intake ie. more died.
– 9.2% for women in the highest quartile of soy protein intake ie. less died.
The “5-year recurrence rates” were:
– 13.0% for women in the lowest quartile of soy protein intake ie. more recurrences.
– 8.9% for women in the highest quartile of soy protein intake ie. less recurrences.
From the report: “The inverse association was evident among women with either ER‐positive or ER-negative breast cancer and was present in both users and non-users of tamoxifen.”
Reference: “Soy Food Intake and Breast Cancer Survival”, Journal of the American Medical Association, 2009 Dec 9; 302(22): 2437–2443; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2874068/
In Contrast, the Association of Animal Hormones in Meat & Dairy Products with Cancers of the Female Reproductive System:
A 2005 science report concludes: “increased consumption of animal-derived food may have adverse effects on the development of hormone-dependent cancers.”
They state: “Meat was most closely correlated with the breast cancer incidence (r=0.827), followed by milk (0.817) and cheese (0.751)… Milk was most closely correlated with the incidence of ovarian cancer (r=0.779), followed by animal fats (0.717) and cheese (0.697)… Milk was most closely correlated with corpus uteri cancer (r=0.814), followed by cheese (0.787). SMRA revealed that milk plus cheese make the most significant contribution to the incidence of corpus uteri cancer ([R]=0.861)...
Among dietary risk factors, we are most concerned with milk and dairy products, because the milk we drink today is produced from pregnant cows, in which estrogen and progesterone levels are markedly elevated.”
Reference: “The possible role of female sex hormones in milk from pregnant cows in the development of breast, ovarian and corpus uteri cancers”, Medical Hypotheses, 2005;65(6):1028-37; at http://www.sciencedirect.com/science/article/pii/S0306987705003543 and https://www.ncbi.nlm.nih.gov/pubmed/16125328
Click the following links for many more science and news reports on:
i) the Diseases Associated with Red Meat Consumption and
ii) the Diseases Associated with Dairy Consumption and
iii) the Diseases Associated with Chicken Consumption
Regards Soy versus Prostate Cancer:
“The Role of Soy Foods in Prostate Cancer Prevention and Treatment” is a video clip
by Dr Michael Greger MD at https://www.youtube.com/watch?v=oPZk6AEP0IY – Some excerpts “A compilation of 13 “observational studies” on soy food consumption and the risk of prostate cancer found that soy foods appear to be “protective.” … In the 70s, more than 12,000 Adventist men were asked about their use of soy milk, and then, they were followed for up to 16 years to see who got cancer, and who did not. So: “Does high soy milk intake reduce prostate cancer incidence?” “Frequent consumption…of soy milk was associated with [a whopping] 70 per cent reduction of the risk of prostate cancer.” Similarly, in a “Multiethnic…Study” that involved a number of groups, soy intake appeared protective in Latinos, too…
Do you think the amazing results Dean Ornish and colleagues got – apparently reversing the progression of prostate cancer with a plant-based diet and lifestyle program – was because of the soy? It wasn’t just a vegan diet, but “a vegan diet supplemented with…[a] daily serving of tofu [and] a…soy protein [isolate powder].” There have been studies showing men given soy protein powders develop less prostate cancer than the control group, but what was the control group getting? Milk protein powder.
Those randomized to the [dairy] milk group got six times more prostate cancer. But is that from the beneficial effects of soy, or the deleterious effects of the dairy? Dairy products are not just associated with getting prostate cancer, but also dying from prostate cancer. Men diagnosed with prostate cancer who then ate more dairy tended to die sooner. And, “[b]oth low-fat and high-fat dairy consumption were…associated with an increased risk of [a] fatal outcome.”…
the protection associated with plant-based diets may be due to eating a variety of healthy foods.”
The text transcript is at https://nutritionfacts.org/video/the-role-of-soy-foods-in-prostate-cancer-prevention-and-treatment/
From Cancer Causes & Control science journal, a study of 12,395 men: “Frequent consumption (more than once a day) of soy milk was associated with 70 per cent reduction of the risk of prostate cancer.”
Reference: “Does high soy milk intake reduce prostate cancer incidence? The Adventist Health Study (United States)”, Cancer Causes Control. 1998 Dec;9(6):553-7; https://www.ncbi.nlm.nih.gov/pubmed/10189040
From a 2018 Nutrients science journal report: “Prostate cancer (PCa) is the second most commonly diagnosed cancer in men … This meta-analysis provides a comprehensive updated analysis that builds on previously published meta-analyses, demonstrating that soy foods and their isoflavones (genistein & daidzein) are associated with a lower risk of prostate carcinogenesis.”
Reference: “Soy Consumption and the Risk of Prostate Cancer: An Updated Systematic Review and Meta-Analysis”, Nutrients, 2018 Jan 4;10(1); https://www.ncbi.nlm.nih.gov/pubmed/29300347
A study on Soy versus Prostate Cancer, as reported in The American Journal of Clinical Nutrition, concluded: “The results of this analysis suggest that consumption of soy foods is associated with a reduction in prostate cancer risk in men. This protection may be associated with the type and quantity of soy foods consumed.”
The study was a meta-analysis of “15 epidemiologic publications on soy consumption and 9 on isoflavones in association with prostate cancer risk.”
Specifically they found: “Our analysis of studies on soy intake yielded a combined RR/OR [relative risks / odds ratios] of 0.74…” That infers a 26% lower risk of prostate cancer among people with the higher intakes of soy.
Furthermore “When separately analyzed, studies on nonfermented soy foods yielded a combined RR/OR of 0.70…” That infers a 30% lower risk.
Also that “those on fermented soy foods yielded a combined RR/OR of 1.02…” which infers no significant change in risk.
And “The analysis of studies on isoflavones yielded a combined RR/OR of 0.88” which infers a 12% lower risk.
Reference: “Soy consumption and prostate cancer risk in men: a revisit of a meta-analysis”, The American Journal of Clinical Nutrition, April 2009, vol. 89 no. 4 1155-1163; at http://ajcn.nutrition.org/content/89/4/1155
A 2017 study concludes that “some phytoestrogens may have a role in DECREASING the risk of prostate cancer.” Soy contains phytoestrogens like daidzein, genistein and glycitein among others. Published in the International Journal of Food Science Nutrition: “This updated meta-analysis was performed to clarify the relationship between phytoestrogens and prostate cancer risk.
Twenty one case-control and two cohort studies were finally selected for this meta-analysis, totaling 11,346 cases and 140,177 controls.
Regards the Odds Ratios (ORs) for the disease: “Analytical results showed that daidzein (OR = 0.85; 95% CI: 0.75-0.96), genistein (OR = 0.87; 95% CI: 0.78-0.98), and glycitein (OR = 0.89; 95% CI: 0.81-0.98) were associated with a reduction of prostate cancer risk…
The results support the notion that some phytoestrogens may have a role in decreasing the risk of prostate cancer…”
Reference: “Phytoestrogens and risk of prostate cancer: an updated meta-analysis of epidemiologic studies”, Int J Food Sci Nutr. 2017 Feb;68(1):28-42; at https://www.ncbi.nlm.nih.gov/pubmed/27687296
Other Health Benefits Associated with Soy Consumption:
Dr Greger clip on soy as a “Waistline Slimming Food: A biological understanding of why soy may result in less abdominal fat” at https://www.youtube.com/watch?v=pMMEZ41DGVM
Text transcript at https://nutritionfacts.org/video/waistline-slimming-food/
From the Scientific Reports journal, regards colorectal cancer (CRC): “Fourteen cohort studies … containing a total of 1,903,459 participants … soybean intake was associated with a decreased risk of CRC…” The relative risk (RR) was 0.85; a 15% lower risk.
In conclusion: “Findings from our meta-analysis supported an association between higher intake of legume and a reduced risk of CRC.”
Reference: “Dietary legume consumption reduces risk of colorectal cancer: evidence from a meta-analysis of cohort studies.” Sci Rep. 2015 Mar 5;5:8797; https://www.ncbi.nlm.nih.gov/pubmed/25739376
Regards Soy versus Lung Cancer a report in the American Journal of Clinical Nutrition concluded: “In a large-scale, population-based, prospective study in Japan, isoflavone intake was associated with a decreased risk of lung cancer in never smokers.”
The study was of 36,177 men and 40,484 women. The isoflavone intake “was estimated by genistein content from soy foods.” Specific findings include: “In men we found an inverse association between isoflavone intake and risk of lung cancer in never smokers”. Inverse means that higher intake was associated with lower rates of cancer. The hazard ratio (HR) for the “highest compared with the lowest quartile of isoflavone intake” was 0.43. A similar association was seen in never-smoking women with a HR of 0.67.
Reference: “Isoflavone intake and risk of lung cancer: a prospective cohort study in Japan”, Am J Clin Nutr. 2010 Mar;91(3):722-8; at https://www.ncbi.nlm.nih.gov/pubmed/20071645
The Official Journal of the European Menopause and Andropause Society: “Long-term safety studies suggest that women who consume a diet high in [soy] isoflavones may have a lower risk of endometrial and ovarian cancer.”
Reference: “Phytoestrogens for menopausal symptoms: A review”, Maturitas, June 2012, Volume 72, Issue 2, Pages 157–159; at http://www.maturitas.org/article/S0378-5122(12)00110-7/fulltext
Regards endometrial cancer a 2012 report in the Journal of the National Cancer Instituteconcluded: “This study suggests that greater consumption of isoflavone-containing foods is associated with a reduced risk of endometrial cancer in this population of nonhysterectomized postmenopausal women.”
The study of 46,027 women assessed risks for “endometrial cancer associated with dietary intake of legumes, soy, and tofu, and for total isoflavones and specific isoflavones (daidzein, genistein, or glycitein)” the three of which are present in soy.
Specifically they found that the reduced relative risks (RR) were:
– 0.66 for isoflavone intake, highest vs lowest quintile, ≥7.82 vs <1.59 mg per 1000 kcal/d.
– 0.64 for daidzein intake, highest vs lowest quintile, ≥3.54 vs <0.70 mg per 1000 kcal/d.
– 0.66 for genistein intake, highest vs lowest quintile, ≥3.40 vs <0.69 mg per 1000 kcal/d
Reference: “Legume, soy, tofu, and isoflavone intake and endometrial cancer risk in postmenopausal women in the multiethnic cohort study”, Journal of the National Cancer Institute, 2012 Jan 4;104(1):67-76; at https://www.ncbi.nlm.nih.gov/pubmed/22158125
From a 2013 article titled “Soy isoflavone: The multipurpose phytochemical (Review)” the introduction: “Soy isoflavones are compounds found in soybean and soybean products. They have been reported to possess numerous physiological properties, such as antitumor, anti-menopausal (female) osteoporosis and anti-aging. They have also been reported to improve learning and memory skills in menopausal women and aid in the prevention and treatment of heart disease, diabetes and Kawasaki disease (KD). In this review, the effects of soy isoflavones on various diseases were analyzed. Based on the analysis, it was hypothesized that the function of soybean isoflavones in the prevention and treatment of various diseases results from their phytoestrogen and antioxidant properties…”
Reference: Biomedical Reports, 2013 Sep; 1(5): 697–701; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3916987/
A 2017 Report on Soy Isoflavone and Improved Mental (Cognitive) Ability states: “Six soy isoflavone studies showed positive cognitive effects of medium size. Greater benefits were seen in women who were <10 years postmenopausal and supplemented for <6 months… Supplementation with either soy isoflavone or resveratrol improved executive function and memory domains of cognitively normal older adults in half of the included studies, mostly with medium effect sizes…”
Reference: “Does phytoestrogen supplementation improve cognition in humans? A systematic review”, Annals of the New York Academy of Science, 2017 Sep;1403(1):150-163; at https://www.ncbi.nlm.nih.gov/pubmed/28945939
Soy Foods Reduce Inflammation? 2013 report in the Journal of the Academy of Nutrition and Dietetics concluded: “This study suggests that soy food consumption is related to lower circulating levels of [these inflammatory markers] IL-6, TNFα, and soluble TNF receptors 1 and 2 in Chinese women.”
Further notes: “Our aim was to evaluate whether higher intake of soy foods was inversely associated with inflammatory markers in 1,005 middle-aged Chinese women… including interleukin-6 (IL-6), IL-1β, tumor necrosis factor-α (TNFα), soluble IL-6 receptor, soluble GP130, soluble TNF receptors 1 and 2, and C-reactive protein, across categories of soy food intake…”
Reference: “Soy Food Intake and Circulating Levels of Inflammatory Markers in Chinese Women, J Acad Nutr Diet. 2012 Jul; 112(7): 996–1004.e4; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC
Regards Soy and Bone Mineral Density and Content the Osteoporosis International journal stated: “Recent interest has been shown in the potential beneficial effects of phytoestrogens on bone health. As the early years of menopause are a period of rapid bone loss, and the risk for osteoporosis increases substantially, the habitual intake of soy protein and isoflavones may play a role in the retardation of bone loss… This study demonstrated that, among women after the initial few years postmenopausal, soy protein/isoflavones intake had a modest but significant association with hip BMD [bone mineral density] as well as total body BMC [bone mineral content)… among the later postmenopausal women, we noted a dose-response relationship with increasing higher BMD values at the trochanter, intertrochanter as well as the total hip and total body with increasing soy protein intake quartiles…”
Reference: “Soy protein consumption and bone mass in early postmenopausal Chinese women”, Osteoporos Int. 2003 Oct;14(10):835-42; at https://www.ncbi.nlm.nih.gov/pubmed/12920508
Regards Soy & Thyroid Health:
From the official journal of the American Thyroid Association, 2006: “hypothyroid adults need NOT avoid soy foods.”
Further quote: “In total, 14 trials… were identified in which the effects of soy foods or isoflavones on at least one measure of thyroid function was assessed in presumably healthy subjects… With only one exception, either NO effects or only very MODEST changes were noted in these trials. Thus, collectively the findings provide LITTLE evidence that in euthyroid, iodine-replete individuals, soy foods, or isoflavones adversely affect thyroid function.
In contrast, some evidence suggests that soy foods, by inhibiting absorption, may increase the dose of thyroid hormone required by hypothyroid patients. However, hypothyroid adults need NOT avoid soy foods…”
Reference: “Effects of soy protein and soybean isoflavones on thyroid function in healthy adults and hypothyroid patients: a review of the relevant literature”, Thyroid, 2006 Mar;16(3):249-58; at http://www.ncbi.nlm.nih.gov/pubmed/16571087
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From Nutrients journal, 2016: “the human research SUPPORTS the safety and benefits of soyfoods. In support of safety is the recent conclusion of the European Food Safety Authority that isoflavones do NOT adversely affect the breast, thyroid or uterus of postmenopausal women.”
Reference: “Soy and Health Update: Evaluation of the Clinical and Epidemiologic Literature”, Nutrients, 2016 Dec; 8(12): 754; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5188409/
From the 2015 report of the European Food Safety Authority (EFSA): “Thyroid hormones levels were NOT changed following intake of isoflavones from food supplements.” And that was at supplemental doses of 35–150 mg/day.
Further notes from the abstract: “Isoflavones are naturally occurring substances which can be found in, among other sources, soy, red clover and kudzu root… A systematic review was performed to investigate whether an association could be found between intake of isoflavones from food supplements and adverse effects on the three target organs in peri- and post-menopausal women…” The target organs being “mammary gland, uterus and thyroid.”
Reference: “Scientific opinion on the risk assessment for peri‐ and post‐menopausal women taking food supplements containing isolated isoflavones”, EFSA Journal Volume 13, Issue 10, October 2015; at http://onlinelibrary.wiley.com/doi/10.2903/j.efsa.2015.4246/full
From Menopause journal 2014: “The outcomes observed in this study suggest soy protein and isoflavone consumption does NOT adversely affect and MAY EVEN PRESERVE thyroid functionin postmenopausal women…”
Reference: “Effect of Soy Isoflavones on Thyroid Hormones…”, Menopause, 2014 Oct; 21(10): 1136–1142; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4160414/
Journal of Medicinal Food – the study’s conclusion: “These results indicate that in this group of healthy iodine-replete subjects, soy isoflavones do NOT adversely affect thyroid function.”
Further notes: “In a randomized, double blind, placebo-controlled study, we investigated the effect on thyroid function of a daily supplement containing 90 mg (aglycone weight) of total isoflavones/day versus placebo in 38 postmenopausal women, 64-83 years old, not on hormone replacement therapy… Intragroup differences for all three measures were statistically indistinguishable at 6 months, and levels were similar between the isoflavone supplement and placebo groups at each measurement…”
Reference: “Isoflavone supplements do not affect thyroid function in iodine-replete postmenopausal women”, Journal of Medicinal Food, 2003 Winter;6(4):309-16; at https://www.ncbi.nlm.nih.gov/pubmed/14977438
According to Dr Todd B. Nippoldt, MD of the highly-respected Mayo clinic: “there’s no evidence that people who have hypothyroidism should avoid soy completely.”
A report in the Indian Journal of Medical Research states: “Modest reduction in serum free T3 levels in the isoflavone group in the absence of any effect on other thyroid parameters might be considered clinically unimportant.”
That was regards a study titled “Evaluation of effect of isoflavone on thyroid economy & autoimmunity in oophorectomised women: A randomised, double-blind, placebo-controlled trial.”
They also noted: “the mean change in various thyroid parameters at 12 wk from baseline was NOT significantly different between the two groups. MSS [menopause symptom score] was also significantly DECREASED at 9 and 12 wk from baseline with isoflavones… with significant improvement in urogenital symptoms compared to placebo.
Isoflavones did NOT significantly affect other parameters during study period. There were NO serious adverse events reported and the proportion of patients experiencing adverse events was similar between the two groups.”
(Capitalised emphasis added)
Reference: “Evaluation of effect of isoflavone on thyroid economy & autoimmunity in oophorectomised women: A randomised, double-blind, placebo-controlled trial”, Indian Journal of Medical Research, 2011 Jun; 133(6): 633–640; at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3135991/
Soy Consumption Associated with Reduced Incidence of Thyroid Cancer.
From the American Association for Cancer Research: “The consumption of traditional and nontraditional soy-based foods and alfalfa sprouts were associated with REDUCED RISK of thyroid cancer.”
Further: “Of the seven specific phytoestrogenic compounds examined, the isoflavones, daidzein and genistein… and the lignan, secoisolariciresinol… were most strongly associated with RISK REDUCTION. Findings were similar for white and Asian women and for pre- and postmenopausal women…”
Reference: “Phytoestrogens and thyroid cancer risk: the San Francisco Bay Area thyroid cancer study”, Cancer Epidemiology, Biomarkers & Prevention, 2002 Jan;11(1):43-9; at https://www.ncbi.nlm.nih.gov/pubmed/11815400
Click this link for a page with many science reports on the association of eating meat with higher rates of several cancers, heart disease, diabetes & mortality; also this link for a page with many reports on the association of dairy consumption and higher rates of several cancers, diabetes, osteoporitic bone fractures, parkinsons disease & mortality (meaning earlier premature death).
2. Reports by Doctors & Nutrition Experts on the Benefits of Soy:
From an article by Dr Holly Wilson MD: “A Vegan Doctor Addresses Soy Myths and Misinformation” some excerpts: “Misinformation regarding soy’s relationship to cancer largely stems from confusion around the presence of phytoestrogens in soy. Phytoestrogen is not estrogen. Estrogen and testosterone are steroid hormones, and occur naturally in both sexes of humans, as well as in animals used for food. They help regulate sexual function and secondary sexual characteristics, in addition to nonsexual cellular functions. While estrogen plays many important beneficial roles in humans, it also naturally promotes proliferation of cells, and, at high levels, can increase risk of some cancers by encouraging cells to multiply more than they usually would. Hormone replacement therapy in postmenopausal women (specifically, taking only estrogen) has also been implicated in cancer growth.
While soy does not contain estrogen, animal foods do. Many consumers are aware that animals used for meat and dairy are commonly supplemented with synthetic growth hormones, but what they don’t consider is that animal flesh and cow milk also contain their own naturally occurring estrogen— and this is true even of “grass-fed” and “organic” animals. Furthermore, meat, dairy and eggs all contain phytoestrogens; they are pervasive in our food, both plant and animal-derived, and you are not avoiding them entirely by avoiding soy…”
Article at http://freefromharm.org/health-nutrition/vegan-doctor-addresses-soy-myths-and-misinformation/
From an article by Dr Neal Barnard with Dr Xiao Ou Shu titled “No Debate: Soy is Beneficial to Health” an excerpt: “There’s no debate: Soy is beneficial to your health. Soy products have been shown beneficial for lung cancer prevention and survival, prostate cancer prevention, heart health and diabetes, bone health, inflammation, and hot flashes, among other conditions…”
Article at http://www.pcrm.org/nbBlog/no-debate-soy-is-beneficial-to-health
From “The Startling Truth About Soy” by Dr. Rosane Oliveira, DVM, PhD – some excerpts: “there is a large body of scientific work which convincingly demonstrates that soy decreases… cancer risks and also lowers cancer recurrence rates.
Early research conducted at University of Southern California suggests that women who have one serving of soy-milk or tofu daily are 30 percent less likely to develop breast cancer.
Another study shows that soy can help breast cancer survivors; women who ate more soy had 29 percent lower mortality rates and 36 percent lower recurrence rates.
Further research shows that the increased survival rate and decreased risk of cancer recurrence may be due to soy phytoestrogens’ effect on BRCA and other breast cancer genes (turning those tumor suppressor genes back “on”.)…
A meta-analysis published in Fertility and Sterility which was based on more than 50 treatment groups, showed that soy products do NOT affect reproductive hormones, including testosterone levels, in men.
The American Journal of Clinical Nutrition published an analysis of 14 studies which showed that an increased intake of soy actually reduced the risk of prostate cancer by 25% while risk was reduced 30% when ingesting nonfermented soy products like soymilk and tofu…
Soy can be found in both its GMO and non-GMO forms. Most GMO in the U.S. is fed to livestock while the majority of soy food manufacturers use non-GMO soy; non-GMO tofu, tempeh, and soymilk are widely available and clearly labeled non-GMO. And by law all “organic” products in the U.S. exclude GMOs. If this is a concern for you, just make sure to choose organic soy products to ensure you are buying non-GMO soy.
A Few Rules Of Thumb When Eating Soy… Like many foods, too much of a good thing is still too much. A good guideline is to keep your soy consumption down to three or five servings daily of whole and minimally-processed soy.
Stick to whole, unprocessed forms of soy which provide you with good quality, health promoting protein. Whole soy includes edamame and roasted soynuts. Minimally-processed soy includes tofu and soymilk. Fermented soy can be enjoyed as tempeh, natto and miso. For an added bonus, try calcium-set tofu which can be one of the richest sources of calcium in a plant-based diet.
Avoid or drastically reduce consumption of highly-processed soy, i.e. soy protein concentrates or isolates, and soy ‘junk’ food like soy cheese and some meat substitutes…”
From the article at http://ucdintegrativemedicine.com/2015/06/the-startling-truth-about-soy/
From an article titled “The Truth About Soy” by best-selling author John Robbins – excerpt: “What follows is my attempt to provide an objective appraisal of both the benefits and the dangers of soy… In my view, the best way to take advantage of soy’s health benefits is to follow the example of the traditional Asian diets. As a population, these are cultures that, when they have eaten their traditional diets, have tended to be healthier and live longer than Americans. The Okinawa Japanese, the longest living people in the world, average 1-2 servings of soy each day. They have traditionally eaten regular but moderate amounts of whole soy foods such as tofu, soymilk, and edamame, as well as the fermented versions, tamari, and miso. These are the soy foods that I prefer to eat — rather than the soy products made with soy protein isolates, soy protein concentrates, hydrolyzed soy protein, partially hydrogenated soy oil, etc. Whole soy foods are more natural, and are the soy foods that have nourished entire civilizations for centuries…
John Robbins is the author of nine bestsellers that have collectively sold more than 3 million copies and been translated into 31 languages. He is founder of EarthSave and co-founder and president of The Food Revolution Network.”
Article at https://foodrevolution.org/blog/the-truth-about-soy/
Article by Dr. Joel Kahn “Is Soy Really A Health Food? A Doctor Settles The Debate…” some excerpts: “There is both older and brand-new data regarding soy and health that should put you at ease about eating organic tofu, edamame, and tempeh…
The Singapore Chinese Health Study examined more than 52,000 men and women free of chronic diseases at entry between 1993 and 1998 and followed them all the way through 2011. During that time, there were more than 10,000 deaths. A pattern of eating a vegetable-, fruit- and soy-rich diet was associated with up to a 25 percent LOWER risk of dying during the study period and was also linked to fewer heart and cancer deaths…
Japanese researchers performed an evaluation of research and identified studies that showed everything from a slight to a significant reduction in breast cancer with increased soy food intake. Additionally, a meta-analysis of 35 studies from Asian countries was performed to examine soy intake and breast cancer risk. Soy intake significantly reduced breast cancer risk by 40 percent in both pre- and postmenopausal women in these countries…
Chinese researchers studied 1,312 cases of first-time heart attack sufferers and 2,235 control subjects. An unhealthy dietary pattern increased the risk of heart attack while an increased intake of vegetables, fruits, and tofu were associated with a significant drop in heart attack rates…
A meta-analysis of men diagnosed with prostate cancer found that the risk of this serious disease was cut in half by regular ingestion of soy and soy isoflavones…
In southern China, 500 women with ovarian cancer were compared to 500 controls, and the amount of soy products eaten was assessed. Regular soy intake was associated with a dramatically lower rate of ovarian cancer with a dose-response relationship, meaning the more soy the women ate the lower their risk became…”
Article at https://www.mindbodygreen.com/0-29364/is-soy-really-a-health-food-a-doctor-settles-the-debate.html
From a Dr Joel Fuhrman article “Don’t Fall for the Myths About Soy” – excerpts: “Contrary to the negative soy information floating about in today’s technological world, the scientific consensus shows soy is essentially beneficial. Actually, soy is the subject of some of the worst health misinformation on the internet. We need to tune out this misinformation and follow the science. Greater intake of soy foods is linked to a decrease in the risk of breast cancer, prostate cancer, and cardiovascular disease…
Since estrogen causes breast cancer cells to proliferate, and cumulative estrogen exposure increases breast cancer risk, there was an early theory that there might be a link between soy foods and breast cancer. At that time, however, in Asian countries, where soy was a staple food, breast cancer rates were much lower than those in the United States. This paradox launched hundreds of studies. The results of some individual studies were neutral, and, importantly, no studies in humans have suggested an increase in breast cancer risk; most show a decrease.
Overall, the research suggests that soy intake helps to protect against initial breast cancer development (especially postmenopausal breast cancer), breast cancer recurrence, and breast cancer mortality. There is no more soy breast cancer controversy.
Important to note: soy appears to be most protective when eaten during adolescence, when breast tissue is most sensitive to influences from the diet and environment.
Does soy reduce the risk of other cancers? Yes. Soy isoflavones have additional anti-cancer effects. In a 2009 meta-analysis, higher soy intake was associated with a 26 percent decrease in prostate cancer risk. Soy has also been linked to decreases in risk of lung, stomach, and colorectal cancers….”
Article at https://www.drfuhrman.com/learn/library/articles/104/dont-fall-for-the-myths-about-soy
From “Is Soy Safe?” by Brenda Davis RD (Registered Dietitian) – excerpt: “In my opinion, soy is not only safe, but potentially beneficial. Soy has a long history of use in Asia, and within vegetarian populations throughout the world. Two of the healthiest, long-lived populations in the world – the Okinawan Japanese and the Seventh-day Adventists in Loma Linda California – are frequent soy consumers. The traditional Okinawan diet derives about 5-6% of calories from soy or about 2 servings a day. If soy foods were dangerous, its effects would be reflected in the health and longevity of these populations. Soy has been extensively researched – about 2,000 new studies on soy are released yearly. The value of soybeans for human health depends on the form and quantity eaten…”
Article at http://www.brendadavisrd.com/is-soy-safe/
For more reports about the long living people of Okinawa and the Californian Seventh-day Adventists – with the longest known lifespans and healthspans of any human populations – see further below and also this page about the health benefits of diets high in unrefined carbohydrates and also this page on the health benefits of plant-based vegan vegetarian diets.
Article titled “The Top 5 Soy Myths” by Judith C. Thalheimer, RD (Registered Dietitian) – quote: “Soyfoods are the subject of several popular misconceptions. Today’s Dietitian looks at the latest research to bring the facts to light.
Soy: It’s a high-quality source of protein, containing all of the essential amino acids; it’s packed with vitamins and minerals; it has fiber (both soluble and insoluble), omega-3 and omega-6 fatty acids, no cholesterol, and very little saturated fat compared with meat. It’s been touted for reducing the risk of coronary heart disease, osteoporosis, and some forms of cancer, and there’s clinical evidence to back up these assertions. But there’s also research (and media speculation) saying that soy can be detrimental to our health.
What accounts for the conflict, what are the facts, and what advice should nutrition professionals give to clients? Here’s the latest information on five common concerns about soy…”
The myths that she then rebuts are in regards to misinformation that is spread about GMO soy, thyroid illness, breast cancer, feminization in men, infant formula, childhood growth and reproductive development.
See the full article at: http://www.todaysdietitian.com/newarchives/040114p52.shtml
Dr Greger clip “Too Much Soy May Neutralize Benefits: Vegans consuming 7 to 18 servings of soy foods a day may end up with circulating IGF-1 levels comparable to those who eat meat” at https://www.youtube.com/watch?v=Rul79Nxxhy4
Text at https://nutritionfacts.org/video/too-much-soy-may-neutralize-plant-based-benefits/
Dr Greger clip “How Much Soy Is Too Much? To maintain the low IGF-1 levels associated with a plant-based diet, one should probably eat no more than 3-5 servings of soy foods a day” at https://www.youtube.com/watch?v=osAJOlSFdEo
Text at https://nutritionfacts.org/video/how-much-soy-is-too-much/
Dr Greger clip “How Much Soy Is Too Much? To maintain the low IGF-1 levels associated with a plant-based diet, one should probably eat no more than 3-5 servings of soy foods a day” at https://www.youtube.com/watch?v=osAJOlSFdEo
Text at https://nutritionfacts.org/video/how-much-soy-is-too-much/
“All About Soy…” Molly Patrick with Brenda Davis RD – “A few weeks ago I video chatted with author and Registered Dietitian Brenda Davis, and we dedicated an entire hour to the heated, misunderstood, scrutinized, feared and often villainized topic of soy…” Article & audio are at http://cleanfooddirtygirl.com/all-about-soy-i-brought-in-an-expert-green-goddess-golden-milk-smoothie/
3. Reports on the Soy-consuming Japanese Okinawans, their Long Lives & Good Health:
Some items regards one of the best-documented examples of a long-living population, low rates of chronic disease and a plant-based diet including soy foods:
“The elderly of Okinawa [islands south of Japan] enjoy what may be the longest life-expectancy in the world, and are also known for enjoying the relatively good health while doing so. The three leading killers in the West – coronary heart disease, stroke, and cancer – occur in Okinawans with the lowest frequency in the world…
Compared to Westerners, the islanders age slowly and are about 80% less likely to get heart disease. They’re also a quarter less likely to get breast or prostate cancer. In addition, they have half the risk of getting colon cancer and are less likely than Westerners to get dementia. On average they spend 97% of their lives free of any disabilities…”
“People from the Ryukyu Islands (of which Okinawa is the largest) have a life expectancy among the highest in the world… the daily diet is almost entirely plant based… The traditional Okinawan diet… ”
“A 25-year study of elder Okinawans credits at least two-thirds of their robust health to lifestyle choices rather than good genes. In stark contrast to American habits, Okinawans eat a vegetable-based diet low in both calories and fats, and rich in soy foods, and they exercise regularly.
“Never in the history of nutrition research has the evidence been more clear and consistent,” wrote Bradley J. and D. Craig Willcox, twin brothers who have written “The Okinawa Program” about the long-running study with co-author Dr. Makoto Suzuki. “A high-carbohydrate, low-calorie, plant-based diet is the best for long-term health.”
Indeed, Okinawans seem to lose their longevity when they migrate to the West or adopt a US-style diet. For instance, the life expectancy of Okinawans living in Brazil drops 17 years, researchers say. Even young people remaining in Okinawa are succumbing to the lure of McDonald’s and the fast-food way of life, the scientists say, driving up their cholesterol levels and other heart-disease risks.
But it’s not just diet that has helped 400 living Okinawans reach age 100 – a rate three to six times higher than in the United States. Also in the Okinawans’ favor, the researchers say, is their practice of martial arts exercises, a positive spiritual attitude, and a low-stress way of living with its own, slower pace they call “Okinawa time.”…
– from http://www.okicent.org/news/boston_globe.html
“Elderly Okinawans have among the lowest mortality rates in the world from a multitude of chronic diseases of aging and as a result enjoy not only what may be the world’s longest life expectancy but the world’s longest health expectancy. Centenarians, in particular, have a history of aging slowly and delaying or sometimes escaping the chronic diseases of aging including dementia, cardiovascular disease (coronary heart disease and stroke) and cancer. The goal of the Okinawa Centenarian Study is to uncover the genetic and lifestyle factors responsible for this remarkable successful aging phenomenon for the betterment of the health and lives of all people…”
2015 Article: “Why Japan’s Longest-Lived Women Hold the Key to Better Health.” Excerpts: “Okinawa is sort of a Japanese Hawaii… For almost a thousand years, this Pacific archipelago has maintained a reputation for nurturing extreme longevity. Okinawans over the age of 65 enjoy the world’s highest life expectancy: Men are expected to live to about 84, while women are expected to live to almost age 90. They suffer only a fraction of diseases that kill Americans: a fifth the rate of cardiovascular disease, a fifth the rate of breast and prostate cancer, and less than half the rate of dementia seen among similarly aged Americans…
The traditional Okinawan diet was about 80 percent carbohydrates…
Dairy and meat represented only about 3 percent of their calories…
Top Longevity Foods from Okinawa… bitter melon… Tofu is to Okinawans what bread is to the French and potatoes are to Eastern Europeans: a daily habit. Okinawans eat about eight times more tofu than Americans do today. Along with other soy products, tofu is renowned for helping to protect the heart. Studies show that people who eat soy products in place of meat have lower cholesterol and triglyceride levels, which reduce their risk of heart disease… Okinawan imo is a supercharged purple sweet potato, a cousin of the yellow-orange sweet varieties… turmeric figures prominently in the Okinawan diet as both a spice and a tea… In Okinawa, where centenarians eat rice every day, both brown and white rice are enjoyed. Nutritionally, brown rice is superior. Okinawan brown rice, tastier than the brown rice we know, is soaked in water to germinate until it just begins to sprout, unlocking enzymes that break down sugar and protein and giving the rice a sweet flavor and softer texture… Shiitake mushrooms… Seaweeds in general provide a filling, low-calorie, nutrient-rich boost to the diet. Kombu and wakame are the most common seaweeds eaten in Okinawa…”
Article at http://www.huffingtonpost.com/dan-buettner/okinawa-blue-zone_b_7012042.html
4. Reports that Most Soy is Fed to Livestock Animals:
The Union of Concerned Scientists: “Only about 6% of soybeans grown worldwide are turned directly into food products for human consumption … 70-75% of the world’s soy ends up as feed for chickens, pigs, cows, and farmed fish.”
“An April 2006 report from the USDA Economic Research Service indicates that only a small amount of whole soybeans are used to produce soy foods, and just 2% of soy protein meal is used for human consumption; the rest is used for animal feed…”
Reference: Environmental Health Perspectives, 2006 Jun; 114(6): A352–A358; at
“About 85 percent of the world’s soybeans are processed, or “crushed,” annually into soybean meal and oil. Approximately 98 percent of the soybean meal that is crushed is further processed into animal feed with the balance used to make soy flour and proteins. Of the oil fraction, 95 percent is consumed as edible oil; the rest is used for industrial products such as fatty acids, soaps and biodiesel…” at http://www.oilseedandgrain.com/soy-facts
“Soy cultivation is a major driver of deforestation in the Amazon basin. Seeds from the soybean plant provide high protein animal feed for livestock, and 80% of Amazon soy is destined for animal feed; smaller percentages are used for oil or eaten directly…” at Reference: “Soy Agriculture in the Amazon Basin” at https://globalforestatlas.yale.edu/amazon/land-use/soy
From a 2015 article titled “Soy: The Biggest Food Crop We Never Talk About.
It has slipped quietly into much of what we consume—and its production is straining ecosystems around the world…” Excerpts: “A whopping 75% of the soy produced worldwide in 2013-2014 became animal feed. Here’s how much soy went into making some of the most common animal products on our plates:
CHICKEN: Soy in a 3-oz. serving: 1.87 oz
PORK CHOP: Soy in a 4-oz.serving: 2.74 oz
HAMBURGER: Soy in a 4-oz. serving: 1.57 oz
OMELETTE: Soy in a two-egg (3.09-oz. total) serving: 3.12 oz
GLASS OF MILK: Soy in an 8-oz. serving: 0.22 oz
CHEESE: Soy in a 3.53-oz. serving: 1.11 oz…
The rising demand for soybeans has encouraged farmers large and small around the world to plant more of the crop. Unfortunately, that cultivation is creeping into native forests and grasslands… threatening vulnerable wildlife and increasing carbon emissions through land conversion…”
2017 news report: “Protein-rich soy is now produced in such huge quantities that the average European consumes approximately 61kg each year, largely indirectly by eating animal products such as chicken, pork, salmon, cheese, milk and eggs.
In 2010, the British livestock industry needed an area the size of Yorkshire to produce the soy used in feed. But if global demand for meat grows as expected, the report says, soy production would need to increase by nearly 80% by 2050.
“The world is consuming more animal protein than it needs and this is having a devastating effect on wildlife,” said Duncan Williamson, WWF food policy manager. “A staggering 60% of global biodiversity loss is down to the food we eat. We know a lot of people are aware that a meat-based diet has an impact on water and land, as well as causing greenhouse gas emissions, but few know the biggest issue of all comes from the crop-based feed the animals eat.”
With 23bn chickens, turkeys, geese, ducks and guinea fowl on the planet – more than three per person – the biggest user of crop-based feed globally is poultry. The second largest, with 30% of the world’s feed in 2009, is the pig industry…”
Source article title: “Vast animal-feed crops to satisfy our meat needs are destroying planet”, The Guardian UK newspaper 2017 at https://www.theguardian.com/environment/2017/oct/05/vast-animal-feed-crops-meat-needs-destroying-planet
From AgriFutures Australia: “Of the average 260 million tonnes produced worldwide each year, about 10% is used directly for human foods, about 20% is extracted for oil and the remainder is used for livestock feeds.” That implies around 70% is used for livestock feed. Source: https://www.agrifutures.com.au/farm-diversity/soybeans/
2017 news report: “The hamburger chain Burger King has been buying animal feed produced in soy plantations carved out by the burning of tropical forests in Brazil and Bolivia, according to a new report.
Jaguars, giant anteaters and sloths have all been affected by the disappearance of around 700,000 hectares (1,729,738 acres) of forest land between 2011 and 2015.
The campaign group Mighty Earth says that evidence gathered from aerial drones, satellite imaging, supply-chain mapping and field research shows a systematic pattern of forest-burning.
Local farmers carried out the forest-burning to grow soybeans for Burger King’s suppliers Cargill and Bunge, the only two agricultural traders known to be operating in the area…”
From a 2016 article titled “The Story of Soy” – “Behind beef, soy is the second largest agricultural driver of deforestation worldwide... The main European importers of soy are countries with large industrial-scale pig and chicken production… Consumers should be mindful of the environmental impacts of their diets, and in particular the relationship between soy and animal products. Around 75% of soy worldwide is used for livestock feed. While many people imagine soy is eaten mainly by vegetarians, most of it is consumed indirectly in the form of chicken, pork, beef and farmed fish as well as eggs, milk, cheese and yogurt…” Source: https://www.worldwildlife.org/stories/the-story-of-soy
“Explain Like I’m 5: Why Tofu Consumption Is Not Responsible for Soy-Related Deforestation” at http://www.onegreenplanet.org/environment/why-tofu-consumption-is-not-responsible-for-soy-related-deforestation/
2019 report: “The Cerrado, Brazil’s savanna, covers over 20 percent of the nation’s territory, but it is seeing severe deforestation. A recent report uncovered links between municipalities with the highest levels of deforestation and with significant soy production. Soy is Brazil’s most important and profitable export, but is also used domestically as animal feed and as a biodiesel energy crop.
In 2017, Brazil produced 16.3 million tons of soymeal for its domestic market, and more than 90 percent of that became animal feed, with 50 percent used as chicken feed, 25 percent as pig feed, and 12 percent for beef and dairy cattle feed.”
From World Wide Fund For Nature (WWF): “Most people associate soy with tofu and soy milk. However, only a small portion of soy is consumed directly by humans. In fact, most of the world’s soy crop ends up in feed for poultry, pork, cattle and even farmed fish.
Unbeknownst to most of us, soy is found in almost all commercially produced meat or chicken that we eat.
And unfortunately, the expansion of soy to feed the world’s growing demand for meat often contributes to deforestation and the loss of other valuable ecosystems…
In South America, almost 4 million hectares of forests are destroyed every year, 2.6 million of them in Brazil alone. Although this is lower than in the 1990s, it is still far too high and can largely be blamed on heavily soy-dependent livestock farming.
Limiting consumption of animal-based food products, particularly meat, is one thing people can do to help end this devastating trend…”
5. Debunking Sources of Anti-Soy Misinformation:
Who spreads anti-soy misinformation? In the words of Dr Justine Butler “most anti-soya stories can be traced back to one single group in the US called the Weston A Price Foundation (WAPF).” She adds that the nutrition advice given by the WAPF, which encourages high consumption of animals and their secretions, frequently “contradicts all the leading health advisory bodies in the world.” See below for a larger quote and link to Dr Butler’s article plus links to other debunkings of the WAPF.
In brief the WAPF promotes the consumption of animals. They appear to be behind numerous “astroturf”* websites that are set up to look independent yet have the same sorts of features: a) they’re supposedly run by a kindly and trustworthy mom-like figure; b) the mom-like figure has an apparent qualification in food matters; c) the articles make many claims that encourage people to avoid plant foods and to eat more animals – including saturated animal fats – which is considered to be very unhealthy by respected scientific studies and health institutions; d) the articles lack adequate references to scientific studies or other reports in science journals; e) the links within the articles – that give the surface impression there is independent substance to back up the claims – are very often to other pages on the same or similar sites, in a rather circular manner; f) the articles are written at a basic level of comprehension; g) different articles target a large number of health concerns to funnel people to their websites; h) the general recommendation is to eat more animals; i) the sites often contain praise for the WAPF as well as for articles and books by WAPF-associated people.
Such sites include: EmpoweredSustenance(dot)com, ButterBeliever(dot)com, theHealthyHomeEconomist(dot)com and ButterNutrition(dot)com.
re: * See this TED talk for a general explanation about “Astroturf and manipulation of media messages… veteran investigative journalist Sharyl Attkisson shows how astroturf, or fake grassroots movements funded by political, corporate, or other special interests very effectively manipulate and distort media messages…” at https://www.youtube.com/watch?v=-bYAQ-ZZtEU
Here are excerpts from some refutations – or debunkings – of the Weston Price Foundation:
1/. A general refutation of Weston Price Foundation information by Dr Joel Fuhrman MD … “a board-certified family physician who specializes in preventing and reversing disease through nutritional and natural methods. Author of Eat To Live…”
Excerpts: “This series of articles is devoted entirely to debunking some of today’s most popular – and potentially most dangerous – diet and nutrition myths… because the scientific data is so clear about the fact that eating more that a few small portions of animal products each week is associated with a host of serious diseases.
Conclusive scientific warnings notwithstanding, people continue to flock to diets like these because a) they reinforce existing bad habits, and b) numerous organizations encourage this behavior. One of the more influential organizations is the Weston A. Price Foundation (WAPF)… named in honor of a Cleveland dentist…
WAPF advocates a severely deficient and dangerous diet for infants and children that has the potential to cause a lifetime of medical problems, reduced brain function, and an early death from cancer.
Infants have their best chance of developing normally when they consume breast milk from well-fed mothers. But contrary to a plethora of scientific studies indicating that breast milk should be the only food for the first six months, Sally Fellon, founder and president of WAPF and coauthor (with Mary Enig) of the book ‘Nourishing Traditions’ says that pureed meat (including organ meats) is an excellent early food for babies…
It is well established in the scientific literature that a diet high in saturated fats and low in fruits and vegetables in early childhood is the leading cause of adult cancers. Infants fed cow’s milk instead of breast milk or formula do not get sufficient iron, vitamin C, linoleic acid, or vitamin E, and take in excessive amounts of sodium, potassium, and protein, which can lead to dehydration and kidney damage.
For many years, the American Academy of Pediatricians has warned against the use of any whole cow’s milk during the first year of life after it was found that infants given cow’s milk developed iron deficiency and occult (silent) bleeding of the digestive tract.
The resultant iron deficiency seen in children raised on cow’s milk in early childhood leads to long-term changes in behavior and loss of intelligence that can not be reversed even with correction of the iron deficiency later on in life.
In other words, permanent brain damage can occur from the feeding of whole cow’s milk to babies…
How can an organization offer nutritional advice so out of step with the world’s scientific literature? Part of the blame can be placed at the feet of those who remain loyal to some of the original observations of Weston Price rather than his original intent…
To advocate eating a diet high in saturated fat is to ignore all of the nutritional research-especially of the past 40 years – that links this diet to shorter life spans and higher rates of heart disease and cancer is unconscionable…”
See the full article at http://www.vegsource.com/news/2010/07/the-truth-about-the-weston-price-foundation.html …
2/. A 2010 article by Dr Justine Butler in The Guardian titled “Ignore the anti-soya scaremongers.”
Excerpts: “There’s no evidence that soya is harmful to humans. In fact, both we and the planet would benefit tremendously from eating more…
Soya is the great divider; you’re either for it, or against it. Is this humble pulse really such a demon bean, or is the anti-soya brigade using scare stories and pseudo science to further their own agenda? If you look carefully, most anti-soya stories can be traced back to one single group in the US called the Weston A Price Foundation (WAPF).
WAPF claims to be dedicated to promoting good nutrition by restoring nutrient-dense animal products to the diet – particularly unpasteurised “raw” whole milk. It claims that saturated animal fat is essential for good health and that animal fat intake and high cholesterol levels have no link with heart disease or cancer. They say that vegetarians have lower life expectancy than meat-eaters, and that historically humans have always eaten large amounts of animal fat.
All this, of course, contradicts all the leading health advisory bodies in the world, including the World Health Organisation, American Dietetic Association and the British Medical Association.
This US-based fringe organisation is bent on citing scientifically flawed studies to promote their own agenda and has influenced a vast number of consumers, duping them into thinking of soya as some sort of dietary pariah…
Another of the organisation’s supporters is a man called Dr Stephen Byrnes, who published an article in the Ecologist magazine claiming that vegetarianism is unhealthy and is destroying the environment. He boasted of his high animal fat diet and robust health – and, unfortunately, died of a stroke at 42. There were more than 40 scientific inaccuracies in the said article, including the direct misquoting of scientific studies. Incidentally, the editor of the Ecologist, Zac Goldsmith, is also an honorary board member of the WAPF.
Another of the organisation’s supporters, Kaayla Daniel PhD, sits on the board of directors and has written an entire book attacking soya (The Whole Soy Story). Curiously, this group appears to spend more time attacking soya than promoting the foods they say we should be eating (unpasteurised “raw” milk, cream, cheese, eggs, liver, etc).
One of the concerns raised about soya is that the phytoestrogens (plant hormones) found in soya foods may disrupt sexual development and affect fertility. If there was any evidence for this in humans at all, the UK government would have banned soya infant formula or at least issued health warnings.
Even after commissioning a 440-page investigation into the safety of soya – they have not issued such warnings because there was no evidence for any harmful effect. The 2003 Department of Health’s committee on toxicity report acknowledged that there was no evidence that people who regularly eat high quantities of soya, such as the Chinese and Japanese, have altered sexual development or impaired fertility. It should be remembered that China is the world’s most populous nation, with over 1.3 billion citizens, and who have been consuming soya for over 3,000 years.
In reality, there is no scientific evidence that the consumption of soya is harmful to humans.The majority of what the WAPF says is anecdotal, untrue or based on scientifically flawed animal experiments. First, phytoestrogens behave differently in different species, so animal studies are not applicable to humans. Second, the intestines act as a barrier to phytoestrogens, so artificially boosting levels in animals by injection has no relevance. Finally, many of these experiments have exposed animals to phytoestrogens at levels many, many times higher than those absorbed by people eating soya.
More and more scientists and doctors are acknowledging that the results of animal experiments should not form the basis of a public health policy. Dr Kenneth Setchell, professor of paediatrics at Cincinnati Children’s Hospital, states that mice, rats and monkeys all metabolise soya isoflavones differently from humans and that the only appropriate model for examining human reproductive development is the human infant. About 25% of infants in the US are fed soya formula. Many of them are now well into their late 30s and early 40s. The absence of any reported ill-effects would suggest there are none, either biological or clinical.
In fact, soya beans contain a wide range of valuable nutrients and are an excellent source of protein. Evidence shows that soya protein lowers cholesterol and protects against cardiovascular disease. Soya foods protect against diabetes, menopausal hot flushes and certain cancers. There is good evidence that eating soya foods in adolescence and as an adult lowers the risk of breast cancer. Recent evidence showed that this protective effect of soya also applies to women who have been diagnosed with breast cancer. Soya foods may also help boost bone health and cognitive ability in some people. The number of peer-reviewed scientific studies reporting the beneficial health effects of soya continues to grow.
As a last resort, the soya detractors have attempted to condemn soya by citing the environmental impact soya farming is having on the Amazonian rain forest. They are quite right to be concerned, but people eating soya is not the problem; 80% of the world’s soya production is fed to livestock so that people can eat meat and dairy foods.
Both the rain forests and our health would benefit tremendously if more people switched from animal-based foods to a more plant-based diet, including soya.
The next time you hear some daft story about soya wreaking havoc on human health or the environment, ask where the evidence is.”
3/. Commentary on the Weston A. Price Foundation by John Robbins... “author of Healthy At 100, The Food Revolution, Diet For A New America, and many other bestsellers.” Excerpts: “speaking as someone who has great respect for the work of Weston A. Price, I am sorry to say that to my eyes, the foundation that carries Price’s name today is unfortunately exaggerating what was unbalanced in his work, and abandoning much of what was good… Price discovered many native cultures that were extremely healthy while eating lacto-vegetarian or pesco-vegan diets. Describing one lacto-vegetarian people, for example, he called them, “The most physically perfect people in northern India… the people are very tall and are free of tooth decay.” Yet the foundation that operates under his name is strikingly hostile to vegetarians.Sally Fallon, the foundation’s president, denounces vegetarianism…
I regret to say that those running the Weston A. Price Foundation today seem to have their own agenda. They are proponents of the philosophy that in order to be healthy, people must eat large amounts of saturated fat from animal products. They insist that only with the regular consumption of lard, butter and other full-fat dairy products, and beef, can people derive the nutrients they need to be healthy.
Toward that end, the Foundation has widely publicized an article written by a former member of the Foundation’s Board of Directors, Stephen Byrnes, titled “The Myths of Vegetarianism.”
The article is harshly critical of vegetarian diets, and concludes with an “About the Author” section which states: “Stephen Byrnes… enjoys robust health on a diet that includes butter, cream, eggs, meat, whole milk, dairy products and offal.” In fact, Stephen Byrnes suffered a fatal stroke in June, 2004. According to reports of his death, he had yet to reach his 40th birthday…
(My thorough response to their specific accusations against soy foods can be seen in my latest book — No Happy Cows: Dispatches from the Frontlines of the Food Revolution.)…” For the fuller articles see http://www.vegsource.com/news/2009/11/reflections-on-the-weston-a-price-foundation.html
4/. An article titled “Weston Price’s Appalling Legacy” is at this link https://sciencebasedmedicine.org/sbm-weston-prices-appalling-legacy/