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Studies Showing Adverse Effects of Dietary Soy, 1939-2008 PDF Print E-mail
Tuesday, 26 August 2003 20:55


Additional Studies: For a list of studies showing the toxicity of soy in the US Food & Drug Administration's Poisonous Plant Database, see FDA Soy References. Also see and

Dietary Soy Study Summaries

Sharpless GR and others. Production of goiter in rats with raw and with treated soybean flour.  J Nutr 17 (Jun), 545-55. Unprocessed soybean flour, when fed as part of a diet over seven weeks to rats, makes the thyroid grow to four times its usual size. In addition the amount of iodine required by a rat on this diet is twice the normal amount.

Wilgus HS and others. The goitrogenicity of soybeans. J Nutr, 22, 43-52.  The study found that soybeans are disruptive to the proper functioning of thyroids causing goiters in chicks. When the consumption of soybean oil meal increased from 30% to 60% of their diet, the goiters doubled in size.

Almquist HJ and Merrit JB. Effect of Soybean Antitrypsin on Growth of the Chick. Arch Biochem, 35, 352-4. Raw soybean meal in amounts as small as 5% of daily protein intake in chicks was responsible for close to “maximal growth retardation.”

Pritchard WR and others. Aplastic Anemia of Cattle Associated with Ingestion of Trichloroethylene-Extracted Soybean Oil Meal (Stockman Disease, Duren Disease, Brabant Disease). J Am Vet Med Assoc. 1952 Jul;121(904):1-8. The study was conducted across 44 herds (a total of 1776 cattle), using varying amounts trichloroethylene-extracted soybean oil meal as feed. In most cases calves under six months who were fed 1-3 lbs per day were the first to die from Aplastic anemia. In some cases they died in under fives weeks of consumption. Lacatation females also experienced a mortality rate that was considerably higher. Adults 24 months and older who ate between 1-4 lbs of the feed per day experienced an average 21% death rate.

Liener IE. Soyin, a toxic protein from the soybean. I. Inhibition of rat growth. J Nutr, 49, 527-39. Soyin, in levels intended to simulate unheated soy flour, after being fed to rats was found to possibly cause “an enforced limitation of food intake with a consequent impairment of growth.”

Eveleth DF and others. Toxicosis of chickens caused by trichloroethylene-extracted soybean meal. J Am Vet Med Assoc, 123, 38-9. During the fifty day period the death rate of birds fed the soybean meal was 26.3%, the death rate of the control group was 4.8%. Of the remaining birds after the 50 day period the average weight of the control group was 1.12 lbs while the weight for those fed the soybean meal was .78 lbs.

Shepard T. Feeding of Soybean and Development of Goiter. Pediatrics 1959;24;854. The author took three cases of goiters in children in which the “thyroid enlargement (was) apparently related to intake of a soybean milk.” Two of the three children were switched to solid food and cows milk and their goiters grew smaller.

Van Wyck JJ and other. The Effects Of A Soybean Product On Thyroid Function In Humans. Pediatrics, 24, 752-60. The study analyzes the effects of soy infant formula, showing that goiters and hypothyroidism are known to occur after consumption. The hindrance of thyroid hormone synthesis cause people to have to increase their intake of iodine. In the case of one child the hypothyroidism was cured by drinking whole cows milk instead of the soy.

Gorill ADL and others. Exocrine pancreatic secretions by calves fed soybean and milk diet proteins. J Nutr, 92(1), 256. Calves fed the milk protein gained an average of 78 grams of weight per day while the calves fed the soy lost an average of 75 grams of weight per day. Those consuming soy protein also experienced a reduced flow rate and reduced levels of protein, trypsin and chemotrypsin in their pancreatic juice. “The soybean flour used in this experiment exerted a marked depression on exocrine pancreatic function of calves, which was detected after the animals had received the high soy diet for 2-5 days.”

Jensen L and others. A Foot Pad Dermatitis in Turkey Poults Associated with Soybean Meal. Poultry Sci, 49, 76-82. There was a frequents occurrence of foot pad dermatis in Turkeys fed soybean meal poults, whereas the occurrence was rare in turkeys fed a diet containing casein, gelatin and corn.

Wallace, GM. Studies on the Processing and Properties of Soymilk. J Sci Food Agri 1971 Oct;22:526-535. In order to neutralize the protease inhibitors (enzymes that inhibit the digestion of protein) in soy, it must be heated to very high temperatures under pressure and for considerable time. This process unfortunately denatures the overall protein content of soy, rendering it largely ineffective.

Joseph, JR. Biological and physiological Factors in Soybeans. JOACS, 1974 Jan;51:161A-170A. In feeding experiments, use of soy protein isolate (SPI) increased requirements for vitamins E, K, D and B12 and created deficiency symptoms of calcium, magnesium, manganese, molybdenum, copper, iron and zinc.

Nutrition during Pregnancy and Lactation. California Department of Health, 1975. Soy is listed as a minor source of protein in Japanese and Chinese diets. Major sources of protein listed were meat including organ meats, poultry, fish and eggs.

Searle CE, ed, Chemical Carcinogens, ACS Monograph 173, American Chemical Society, Washington, DC, 1976. Asians throughout the world have high rates of thyroid cancer.

Chang KC, ed, Food in Chinese Culture: Anthropological and Historical Perspectives, New Haven, 1977. This survey found that soy foods accounted for only 1.5 percent of calories in the Chinese diet, compared with 65 percent of calories from pork.

FDA ref 72/104, Report FDABF GRAS - 258. In 1972, the Nixon administration directed a reexamination of substances believed to be GRAS in the light of any scientific information then available. This reexamination included casein protein which became codified as GRAS in 1978. In 1974, the FDA obtained a literature review of soy protein because, as soy protein had not been used in food until 1959 and was not even in common use in the early 1970s, it was not eligible to have its GRAS status grandfathered under the provisions of the Food, Drug and Cosmetic Act.

Evaluation of the Health Aspects of Soy Protein Isolates as Food Ingredients. Prepared for FDA by Life Sciences Research Office, Federation of American Societies for Experimental Biology, 9650 Rockville Pike, Bethesda, MD 20014, Contract No, FDA 223-75-2004, 1979. In this document, the FDA expresses concern about nitrites and lysinoalanine in processed soy. Even at low levels of consumption--averaging one-third of a gram per day at the time--the presence of these carcinogens was considered too great a threat to public health to allow GRAS status. Soy protein did have approval for use as a binder in cardboard boxes and this approval was allowed to continue because researchers considered that migration of nitrites from the box into the food contents would be too small to constitute a cancer risk. FDA officials called for safety specifications and monitoring procedures before granting of GRAS status for food. These were never performed. To this day, use of soy protein is codified as GRAS only for limited industrial use as a cardboard binder.

Torum, B. Nutritional Quality of Soybean Protein Isolates: Studies in Children of Preschool Age. Soy Protein and Human Nutrition, Harold L Wilcke and others, eds, Academic Press, New York, 1979. A group of Central American children suffering from malnutrition was first stabilized and brought into better health by feeding them native foods, including meat and dairy products. Then for a two-week period these traditional foods were replaced by a drink made of soy protein isolate and sugar. All nitrogen taken in and all nitrogen excreted were measured. The researchers found that the children retained nitrogen and that their growth was "adequate," so the experiment was declared a success. However, the researchers noted that the children vomited "occasionally," usually after finishing a meal; over half suffered from periods of moderate diarrhea; some had upper respiratory infections; and others suffered from rash and fever. It should be noted that the researchers did not dare to use soy products to help children recover from malnutrition, and were obliged to supplement the soy? sugar mixture with nutrients largely absent in soy products, notably vitamins A, D, B12, iron, iodine and zinc.

Casey CE and others. Availability of zinc: loading tests with human milk, cow's milk, and infant formulas. Pediatrics 1981;68(3):394-6. Female subjects consumed 25 mg of zinc with milk or formula, the amount of which was calculated to provide 5 gm of protein, after an eight-hour fast. Blood samples were taken prior to (base line) and at 30-minute intervals for three hours after consumption of zinc. The plasma response with human milk was significantly greater than with cow's milk and all the formulas. The response with cow's milk and a cow's milk-based formula was one third that with human milk; responses with a soy-based and two casein hydrolysate-based formulas were even lower.

Lebenthal E and others. The development of pancreatic function in premature infants after milk-based and soy-based formulas. Pediatr Res 1981 Sep;15(9):1240-1244. Soy formula fed to premature babies caused in increase in digestive enzymes compared to milk-fed babies, indicating low digestibility of soy formula.

Murphy PA. Phytoestrogen Content of Processed Soybean Foods. Food Technology. 1982:50-54. One hundred grams of soy protein, the maximum suggested cholesterol-lowering dose in the FDA-sanctioned health claim, can contain almost 600 mg of isoflavones.

Wenk GL and Stemmer KL. Suboptimal dietary zinc intake increases aluminum accumulation into the rat brain. Brain Res 1983;288:393-395. Zinc deficiency will cause more aluminum to be absorbed into the body in general, and into the brain in particular. Aluminum will be absorbed by competing for binding sites on a zinc-containing ligand. Fluoride and phytates in soy formula will induce zinc deficiency.

Poley JR and Klein AW. Scanning electron microscopy of soy protein-induced damage of small bowel mucosa in infants. J Pediatr Gastroenterol Nutr 1983 May;2(2):271-87. Soy feeding caused damage to small bowel mucosa in 2 infants. The damage was similar to that of celiac disease and consistent with a lectin-induced toxicity.

Tait S and others. The availability of minerals in food, with particular reference to iron. Journal of Research in Society and Health, April 1983;103(2):74?77. When precipitated soy products like tofu are consumed with meat, the mineral blocking effects of the phytates are reduced. The Japanese traditionally eat a small amount of tofu or miso as part of a mineral rich fish broth, followed by a serving of meat or fish.

Ross RK. Effect of in-utero exposure to diethylstilbesterol on age at onset of puberty and on post-pubertal hormone levels in boys," Canadian Medical Association Journal 1983, May 15;128(10):1197-8. Male children exposed during gestation to diethylstilbesterol (DES), a synthetic estrogen that has effects on animals similar to those of phytoestrogens from soy, had testes smaller than normal on maturation.

Ologhobo AD and others. Distribution of phosphorus and phytate in some Nigerian varieties of legumes and some effects of processing. Journal of Food Science. January/February 1984;49(1):199-201. The phytic acid in soy is highly resistant to normal phytate-reducing techniques, such as soaking or long, slow cooking.

Rackis JJ and others. The USDA trypsin inhibitor study. I. Background, objectives and procedural details. Qualification of Plant Foods in Human Nutrition, 1985;35. Diets of soy protein isolate high in trypsin inhibitors caused depressed growth and enlargement and pathological conditions of the pancreas, including cancer, and enlarged thryoid glands in rats. Analyses for this study showed that trypsin inhibitor content of soy protein isolate can vary as much as fivefold. Even low-level-trypsin-inhibitor SPI feeding resulted in reduced weight gain compared to controls. Soy protein isolate and textured vegetable protein made from soy protein isolate are used extensively in school lunch programs, imitation foods, commercial baked goods, diet beverages, meal replacements and fast food products. They are heavily promoted in Third World countries and form the basis of many food giveaway programs.

McGraw MD and others. Aluminum content in milk formulae and intravenous fluids used in infants. Lancet I:157 (1986). Carefully collected human breast milk contained 5 to 20 micrograms aluminum per liter; concentrations were 10 to 20 fold greater in most cow's milk-based formulas and 100-fold greater in soy-based formulas.

Fort P and others. Breast feeding and insulin-dependent diabetes mellitus in children. J Am Coll Nutr 1986;5(5):439-441. Twice as many soy-fed children developed diabetes as those in a control group that was breastfed or received milk-based formula. It was based on this study that the American Academy of Pediatrics took a position of opposition to the use of soy infant formula. This objection was later dropped after the AAP received substantial grants from the Infant Formula Council.

Freni-Titulaer LW and others. Am J Dis Child 1986 Dec;140(12):1263-1267.Soy infant feeding was associated with higher rates of early development in girls, including breast development and pubic hair before the age of eights, sometimes before the age of three.

Tudor RJ and others. Comparative Subacute Effects Of Dietary Raw Soya Flour On The Pancreas Of Three Species, The Marmoset, Mouse and Rat. Food Chem Toxic. 25 (10), 739-45. Ingestion of soy produced enlarged pancreases in mice and “pancreatic adenoma and carcinoma in the rat.”


Dabeka RW and McKenzie AD. Lead, cadmium, and fluoride levels in market milk and infant formulas in Canada. J Assoc Off Anal Chem 1987;70(4):754-7 (1987). Soy based or milk-free formulas contained about 8-15 times more cadmium than milk-based formulas as well as high amounts of fluoride.

Katz SH. Food and Biocultural Evolution: A Model for the Investigation of Modern Nutritional Problems. Nutritional Anthropology, Alan R. Liss Inc., 1987, p 50. During the Chou Dynasty (1134 - 246 BC) the soybean was designated one of the five sacred grains, along with barley, wheat, millet and rice. However, the pictograph for the soybean, which dates from earlier times, indicates that it was not first used as a food; for whereas the pictographs for the other four grains show the seed and stem structure of the plant, the pictograph for the soybean emphasizes the root structure. Agricultural literature of the period speaks frequently of the soybean and its use in crop rotation. Apparently the soy plant was initially used as a method of fixing nitrogen. The soybean did not serve as a food until the discovery of fermentation techniques, sometime during the Chou Dynasty. Katz speculates that the rise of liver cancer in Africa is caused by the introduction of soy foods into the African diet.

El Tiney A. Proximate Composition and Mineral and Phytate Contents of Legumes Grown in Sudan. Journal of Food Composition and Analysis 1989;2:67-68. Soybeans are listed as having some of the highest levels of phytic acid of all legumes. Phytic acid blocks the absorption of zinc, iron, copper and magnesium.

Campbell TC. The Cornell-China-Oxford Project on Nutrition, Health and Environment. 1990; Chen J and others. Diet, Lifestyle and Mortality in China. A study of the characteristics of 65 counties. Monograph, joint publication of Oxford University Press, Cornell University Press, China People's Medical Publishing House. 1990. This exhaustive study of Chinese diets found that legume consumption ranged from 0 to 58 grams per day, with an average of 13 grams. Assuming that two-thirds of this is from soybeans, then consumption averages about 9 grams of soy products per day. Isoflavone content would probably be about 10 mg/day.

Fort P and others. Breast and soy-formula feedings in early infancy and the prevalence of autoimmune thyroid disease in children. J Am Coll Nutr 1990;9:164-167. This study documents the association of soy formula feeding in infancy with autoimmune thyroid problems.

Dabeka RW and McKenzie AD. Aluminium levels in Canadian infant formulate and estimation of aluminium intakes from formulae by infants 0-3 months old. Food Addit Contam 1990;7(2):275-82. Researchers found that aluminum content in soy formula for 1-3 month old infants could result in an intake of 363 micrograms/kg/day (2088 micrograms/day) alone, not including potential contribution from other foods or water.

Hagger C and Bachevalier J. Visual habit formation in 3-month-old monkeys (Macaca mulatta): reversal of sex difference following neonatal manipulations of androgen. Behavior and Brain Research 1991, 45:57-63. Male infants undergo a "testosterone surge" during the first few months of life, when testosterone levels may be as high as those of an adult male. During this period, the infant is programmed to express male characteristics after puberty, not only in the development of his sexual organs and other masculine physical traits, but also in setting patterns in the brain characteristic of male behavior. In monkeys, deficiency of male hormones impairs the development of spatial perception (which, in humans, is normally more acute in men than in women), of learning ability and of visual discrimination tasks (such as would be required for reading.)

Grant G and others. Pancreatic enlargement is evident in rats fed diets containing raw soybeans (Glycine max) or cowpeas (Vigna unguiculata) for 800 days but not in those fed diets based on kidney beans (Phaseolus vulgaris) or lupin seed (Lupinus angustifolius). J Nutr, 123(12), 2207-15. During the initial 150 days of the study, rats fed the soybean diet experienced abnormal levels pancreatic growth. Some of the rats fed the soybean diet also experienced the growth of nodules on the pancreas after 500 days.

Messina MJ and others. Soy Intake and Cancer Risk: A Review of the In Vitro and In Vivo Data," Nutrition and Cancer, 1994, 21:(2):113-131. This study fueled speculation on soy's anti-carcinogenic properties. The authors noted that in 26 animal studies, 65 percent reported protective effects from soy. At least one study was left out, in which soy feeding caused pancreatic cancer, the 1985 study by Rackis. In the human studies listed, the results were mixed. A few showed some protective effect but most showed no correlation at all between soy consumption and cancer rates. ". . the data in this review cannot be used as a basis for claiming that soy intake decreases cancer risk." In a subsequent book, The Simple Soybean and Your Health, Messina recommends 1 cup or 230 grams of soy products per day in his "optimal" diet as a way to prevent cancer.

Hawkins NM and others. Potential aluminium toxicity in infants fed special infant formula. J Pediatr Gastroenterol Nutr 1994;19(4):377-81 (1994). Researchers found aluminum concentrations of 534 micrograms/L in soy formula, as compared to 9.2 micrograms/L in breast milk. The authors concluded that infants might be at risk from aluminium toxicity when consuming formula containing more than 300 micrograms/L.

Chorazy PA and others. Persistent hypothyroidism in an infant receiving a soy formula: case report and review of the literature. Pediatrics 1995 Jul;96(1 Pt 1):148-50. The study describes a case of persistent hypothyroidism in an infant who had received soy formula.

Anderson JW and others. Meta-analysis of the Effects of Soy Protein Intake on Serum Lipids. New England Journal of Medicine, 1995 333:(5):276-82. The FDA’s allowance of a health claim for soy protein is based largely on this meta-analysis, sponsored by Protein Technologies International. However, the study authors discarded eight studies for various reasons, leaving a remainder of 29. The published report suggested that individuals with cholesterol levels over 250 mg/dl would experience a "significant" reduction of 7 to 20 percent in levels of serum cholesterol if they substituted soy protein for animal protein. Cholesterol reduction was insignificant for individuals whose cholesterol was lower than 250 mg/dl. In other words, for most of the population, the substitution of meat with soy will not bring blood cholesterol levels down.

Harras A, ed. Cancer Rates and Risks, 4th Edition, 1996, National Institutes of Health, National Cancer Institute. This report shows that the Japanese, and Asians in general, have lower rates of breast and prostate cancer but much higher rates of other types of cancer, particularly cancer of the esophagus, stomach, pancreas and liver.

Fukutake M and others. Quantification of genistein and genistin in soybeans and soybean products. Food Chem Toxicol 1996;34:457-461. Average Isoflavones consumption in Japan was found to be about 10 mg per day.

IEH assessment on Phytoestrogens in the Human Diet, Final Report to the Ministry of Agriculture, Fisheries and Food, UK, November 1997. This exhaustive report on phytoestrogens, prepared by the British government, failed to find much evidence of benefit and warned against potential adverse effects.

Herman-Giddens ME and others. Secondary Sexual Characteristics and Menses in Young Girls Seen in Office Practice: A Study from the Pediatric Research in Office Settings Network. Pediatrics, 1997 Apr;99:(4):505-512. Investigators found that one percent of all girls now show signs of puberty, such as breast development or pubic hair, before the age of three; by age eight, 14.7 percent of white girls and almost 50 percent of African-American girls had one or both of these characteristics. Our Comment: The widespread use of soy-based formula, beginning in the 1970s, is a likely explanation for the increase in early maturation in girls.

Nagata C and others. Decreased serum total cholesterol concentration is associated with high intake of soy products in Japanese men and women. J Nutr 1998 Feb;128(2):209-13. This study included a survey of soy consumption among Japanese men and women. Consumption of soy products was about 54 grams per day for women and 64 grams per day for men. The total amount of soy protein from these products was 7-8 grams providing about 25 mg Isoflavones.

Irvine CH and others. Phytoestrogens in soy-based infant foods: concentrations, daily intake and possible biological effects. Proc Soc Exp Biol Med 1998 Mar;217(3):247-53. Researchers found that soy formulas provide infants with a daily dose rate of 3 mg/kg body weight total isoflavones, "which is maintained at a fairly constant level between 0-4 months of age. . . . This rate of isoflavone intake is much greater than that shown in adult humans to alter reproductive hormones."

Yaffe K and others. Serum estrogen levels, cognitive performance, and risk of cognitive decline in older community women. J Am Geriatr Soc 1998 Jul;46(7):918-20. Women in the higher estrone quartiles had lower performance on two cognitive tests.

Irvine CH and others. Daily intake and urinary excretion of genistein and daidzein by infants fed soy- or dairy-based infant formulas. Am J Clin Nutr 1998 Dec;68(6 Suppl):1462S-1465S. Researchers found that "young infants are able to digest, absorb, and excrete genistein and daidzein from soy-based formulas as efficiently as do adults consuming soy products.

Eklund G and Oskarsson A. Exposure of cadmium from infant formulas and weaning foods. Food Addit Contam 16(12):509-19 (1999). Cadmium was 6 times higher in soy formulas than cow's milk formulas.

Olguin MC and others. Intestinal alterations and reduction of growth in prepuberal rats fed with soybean [Article in Spanish]. Medicina (B Aires) 1999;59:747-752. Rats fed soy-based chow had reduced growth and an increase in gastrointestinal problems compared to controls.

Nilhausen K and Meinertz H. Lipoprotein(a) and dietary proteins: casein lowers lipoprotein(a) concentrations as compared with soy protein. Am J Clin Nutr 1999;69:419-25. Many studies have shown that soy consumption can lower serum cholesterol levels. These studies have led to claims that soy can prevent heart disease. However, the theory that high cholesterol levels cause heart disease is becoming more and more untenable. Cholesterol levels are not a good marker for proneness to heart disease. However Lipoprotein(a) or Lp(a), does serve as a good marker for heart disease. This study indicates that soy raises Lp(a), meaning that it is likely to contribute to heart disease.

Food Labeling: Health Claims: Soy Protein and Coronary Heart Disease, Food and Drug Administration 21 CFR Part 101 (Docket No. 98P-0683). This US government document allows a health claim for foods containing 6.25 grams of soy protein per serving. The original petition, submitted by Protein Technologies International (a division of Dupont), requested a health claim for isoflavones, the estrogen-like compounds found plentifully in soybeans, based on assertions that "only soy protein that has been processed in a manner in which isoflavones are retained will result in cholesterol-lowering." In 1998, the FDA made the unprecedented move of rewriting PTI's petition, removing any reference to the phytoestrogens and substituting a claim for soy protein, a move that was in direct contradiction to the agency's regulations. The FDA is authorized to make rulings only on substances presented by petition. The abrupt change in direction was no doubt due to the fact that a number of researchers, including scientists employed by the US government, submitted documents indicating that isoflavones are toxic. The regulations stipulate that 25 grams of soy protein per day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of heart disease. Twenty-five grams soy protein can contain from 24-125 mg isoflavones, depending on processing methods. Many letters were written in protest, expressing concerns about mineral blocking effects, enzyme inhibitors, goitrogenicity, endocrine disruption, reproductive problems and increased allergic reactions from consumption of soy products.

Sheehan DM and Doerge DR, Letter to Dockets Management Branch (HFA-305) February 18, 1999. A strong letter of protest from two government researchers at the National Center for Toxicological Research urging that soy protein carry a warning label rather than a health claim.

Ginsburg J and Prelevic GM. Is there a proven place for phytoestrogens in the menopause?" Climacteric, 1999;2:75-78. Quantification of discomfort from hot flashes is extremely subjective and most studies show that control subjects report reduction in discomfort in amounts equal to subjects given soy.

White L. Association of High Midlife Tofu Consumption with Accelerated Brain Aging. Plenary Session #8: Cognitive Function, The Third International Soy Symposium, Program, November 1999, page 26. An ongoing study of Japanese Americans living in Hawaii found a significant statistical relationship between two or more servings of tofu per week and "accelerated brain aging." Those participants who consumed tofu in mid life had lower cognitive function in late life and a greater incidence of Alzheimer's and dementia.

Clarkson TB. Soy phytoestrogens: what will be their role in postmenopausal hormone replacement therapy? Menopause 2000 Mar-Apr;7(2):71-5. Soy did not prevent bone loss when measured at autopsy in female monkeys who had had their reproductive organs removed.

Vincent A and Fitzpatrick LA. Soy isoflavones: are they useful in menopause? Mayo Clin Proc 2000;75:1174-84. "Current data are insufficient to draw definitive conclusions regarding the use of isoflavones as an alternative to estrogen for hormone replacement in postmenopausal women."

North K and Golding J. A maternal vegetarian diet in pregnancy is associated with hypospadias. The ALSPAC Study Team. Avon Longitudinal Study of Pregnancy and Childhood. BJU Int 2000 Jan;85(1):107-113. Vegetarian women are more likely consume more soy than the general population. Incidence of hypospadias was twice as great in vegetarian mothers than in non-vegetarian mothers. Hypospadias is a birth defect due to interrupted development of the penis.

Nakamura Y and others. Determination of the levels of isoflavonoids in soybeans and soy-derived foods and estimation of isoflavonoids in the Japanese daily intake. J AOAC Int 2000;83:635-650. This survey found that average isoflavone consumption in Japan is about 28 mg per day.

Bee G. Dietary Conjugated Linoleic Acids Alter Adipose Tissue and Milk Lipids of Pregnant and Lactating Sows. J Nutr 2000;130:2292-2298. Dietary mixtures for pigs, which are carefully formulated to promote reproduction and growth, allow approximately 1 percent of the ration as soy in a diet based on grains and supplements. (Pigs have a digestive system similar to humans.) The Central Soya Company, Inc. website gives a range of 2.5 percent to 17.5 percent soy in the diet of pigs, citing a number of anti-nutritional components that "have been documented to cause gastrointestinal disturbance, intestinal damage, increased disease susceptibility and reduced performance in pigs."

Nagata C. Ecological study of the association between soy product intake and mortality from cancer and heart disease in Japan. International Journal of Epidemiology Oct 2000; 29(5):832-6. This study contained the following official conclusion: "The present study provides modest support for the preventive role of soy against stomach cancer and heart disease death." However, only the association with lower heart disease death is correct. What the study actually found was that "Soy protein intake was significantly correlated with stomach cancer mortality rate in men" and "soy product intake estimated as total amount as well as isoflavone and soy protein intake were significantly positively correlated with colorectal cancer mortality rates in both sexes." In other words, men who consumed lots of soy had more stomach cancer and men and women who consumed lots of soy had more colorectal cancer. These results are especially interesting as soy proponents often claim that Asians have lower rates of colorectal cancer because they eat more soy.

Strom BL and others. Exposure to soy-based formula in infancy and endocrinological and reproductive outcomes in young adulthood. JAMA 2001 Nov 21;286(19):2402-3. Although reported in the media as a vindication of soy infant formula, the study actually found that soy-fed infants had more reproductive problems and more asthma as adults.

Massey LK and others. Oxalate content of soybean seeds (Glycine max: Leguminosae), soyfoods, and other edible legumes. J Agric Food Chem 2001 Sep;49(9):4262-6. Soy foods were found to be high in oxalates and likely to contribute to kidney stones.

Khalil DA and others. Soy protein supplementation increases serum insulin-like growth factor-I in young and old men but does not affect markers of bone metabolism. J Nutr 2002 Sep;132(9):2605-8. Men consuming soy protein had higher levels of insulin-like growth factor-I (IGF-I) than those consuming milk protein. According to many other studies (but not stated in the report), high levels of IFG-I are also found in rBGH milk and have been implicated in causing hormonal cancers.

Sun CL and others. Dietary soy and increased risk of bladder cancer: the Singapore Chinese Health Study. Cancer Epidemiol Biomarkers Prev. 2002 Dec;11(12):1674-7. People who consumed 92.5 grams of soy per 1000 Kcal were found to be 2.3 times more likely to be at risk for bladder cancer. The results were calculated to factor in levels of education and cigarette consumption in study participants.

Lack G and others. Factors associates with the development of peanut allergy in childhood. N Engl J Med 2003 Mar 13;348(11):977-85. The number of children with life-threatening peanut allergies has tripled during the last decade. This study suggests a link between consumption of soy-based formula and the development of peanut allergies. Scientists at the University of Bristol monitored 14,000 babies in the southwest of England. Among the 49 children who developed a peanut allergy, almost a quarter had consumed soy milk during their first two years. (Less than 5 percent of babies overall receive soy formula in the UK.) According to lead researcher Gideon Lack, "These results suggest that sensitization to peanut may possibly occur. . . as a result of soya exposure."

Conrad S and others. Soy formula complicates management of congenital hypothyroidism. Archives of Disease in Childhood 2004 Jan;89(1):37-40. Soy formula was found to increase the level of thyroid stimulating hormones in infants.

Hogervorst E and others. High Tofu Intake Is Associated with Worse Memory in Elderly Indonesian Men and Women. Dementia and Geriatric Cognitive Disorders 2008;26(1):50-7. The study found that those who ate tofu regularly had worse memory than those who did not. The study also found that tempe consumption increased memory, possibly due to its high levels of folate caused by fermentation.

Banta JP and others. Whole soybean supplementation and cow age class: Effects on intake digestion, performance and reproduction of beef cows. J Anim Sci 2008.86: 1868-78. Experiments conducted found that whole soybean supplement caused increased luteal activity in mature cows at the start of the breeding season . In 2 year old cows it caused less luteal activity than normal.


Comments (20)Add Comment
To vegandr
written by Liz, Mar 01 2014
This couldn't possibly be propaganda by the dairy industry as you say. The dairy industry is all about pasteurized, hormone laden, dead milk and dairy products. This site does not promote that at all. Yes, studies can be made to appear how the person wants them to appear and that is even more probable when it comes to large industries such as soy and conventional farming.
The Sky is Falling! The Sky is Falling!
written by Brian Ansorge, Jan 21 2014
I've been using soy products for the past thirty years. I've consumed between one and two thousand gallons of soy milk.

I avoid animal products, but I am not "religious" about it. My health is great. On my 50th birthday, I biked over seventy miles (with an elevation gain of over 4,000 feet in 35 miles). I can work "circles" around most 18 year olds.

Oh, and I've smoked one cigarette a day for the past 15 years.

Guess which "habit" is worse? Did you guess smoking? Good for you.

Soy is good for me.


written by Unmani Cynthia Groves, Health Care Practice Mgmt. Consultant, Jun 16 2013
Relevant is each one's ability to metabolize foods. Our genetic makeup can be quite different, and even if we can overcome some genetic markers by environmental interaction, there is the issue of primary, secondary and accumulative effects of foods alone or combined that can create toxic burden the system can assimilate or throw off. Apparently some of your readers haven't had a problem with soy, appear to be robust; and metabolize foods very well. It's unclear at what age soy was introduced to them as well, and with the advent of GMO soy and high fructose corn syrup (also GMO) we don't know results during the first year after birth when no other foods are consumed without post market studies. I have yet to see post market studies on humans which I would like to pass on to our state legislators in the US and the FDA. Please email me them if they have been done at Most studies done for government regulation approval are on animals and approved at least in the US more recently on 3-4 month animal studies and not humans. They are often industry funded, not independent studies. Also, it is unclear whether genetic testing of mom and baby was done prior to ingesting soy and its effects on infants for example. It is not clear the difference between ingestng non gmo soy and gmo soy. I have not seen the studies that were done in European Union that "regulated no gmos--GMO soy or high fructose syrup in baby formula until after 6 mo. of age." Those would be valuable studies to see and would be useful to us in America who want to see this regulated particularly at this very young age, since there has been a claim that there are no post market studies on gmo vs non gmo baby formula on soy and high fructose corn syrup. Those studies would have been the easiest to show the impacts on the human organism since no other foods are introduced normally during that time. It could be instrumental in putting to rest the arguments on GMOs that not one meal has been shown the have harmful effects on humans--a claim made by the biotech industry."
We LOVE SOY!, Low-rated comment [Show]
written by PGT, Dec 10 2012
Danny, this not bullshit, but that is nice you can eat soy....but that is not true for many people. Soy is now one of the top 8 allergens in our diets. That is a FACT! ! ! Many people do not even realize their health issues are due to soy allergies and/or intolerance's.

About 10 years ago I was suffering from hives, rashes, violent vomiting after meals that included any type of soy (un-fermented it turns out) and weight gain, even adult acne. It turns out my body cannot tolerate soy. Many members of my family have now also been diagnosed with soy allergies or intolerance. I must avoid soy flour, soybean oil (which some people can still tolerate my allergist told me), soy isoflavones, soy protein of any type. I have had to pay more for my food, as even canned tuna can contain soy. Most bread products have some type of soy. Most diet, health and sport bars or drinks now have soy. Eating in restaurants means no sauces, dressings of any type unless I can read the ingredients. Nothing fried in the event they use soybean oil (vs. corn or olive oil) I found out by getting sick in restaurants on a regular basis but not at home where I was reading every label and eliminating the HIDDEN soy in many foods.
As I have eliminated more soy, my weight stabilized, my skin cleared and I have more energy again. I know I have been getting small amounts of soy when I get hives and rashes, difficulty breathing and stomach issues. Large doses cause violent vomiting within an hour of eating. This is NOT in my mind, as I have eaten, loved the food...and suddenly...find myself rushing to a bathroom. Within 20 minutes I am weak and itchy, but okay. Later I discovered soy in the meal someplace I didn't suspect.
I have become skilled at eating out and not getting sick, but it isn't fun. Soy free food is also more expensive.....which makes me wonder what is behind that!?!?!?!?!
Those of you that claim the "dairy people" are behind this....well, I thought I was lactose intolerant too. After I got sick on soy products and cleaned up my diet....guess what, I am no longer lactose intolerant.
It turned out that most of the "low fat" and "non fat" dairy products were made with some type of soy product or additive. I was not lactose intolerant, but SOY intolerant. Organic, less processed dairy products I can eat without a problem.

I am a 50 year old grandmother..and I am healthy, active size 2 to 4 (in women's clothing). I hike, exercise, scuba-dive and sea kayak...and I eat MEAT! ! ! ! I do focus on vegetables, fruit in moderation, look for less processed foods and lean meats as much as possible. Also, lots of water, limit sugar and caffeine.

Moderation is important, no matter what we eat.
written by Barb, Oct 22 2012
NOT Bullshit at all. There are several people our there who have smoked heavily their entire life, but have not developed lung, throat or other cancers from it.

That does not make cigarette smoking benign OR healthy. That makes those people extremely lucky. Same situation with soy. As for those people who are so quick to call foul on the oodles and OODLES of research, you are likely suffering from cognitive dissonance. This is an easy trap to fall into, and as humans none of us are immune to it.
written by vegandr, Aug 08 2012
Propaganda for the dairy industry. With all the research going on, if you can only list one study every few years... not impressive to people who know there are literally thousands of other studies that state the opposite. You can manipulate statistics to conclude whatever you want. No food is perfect, but if I have to chose between the hormone and antibiotic residues (and inhumane production) of milk or soy... I'll pick soy. Raising 2 children on soy (as part of a varied diet) - 90%+ on growth charts and no health problems.
Soy in Relation to Infants, Children, and overuse for both adults and children/infants
written by Ben, Aug 03 2012
I read every study listed above. So, from the information I gathered I'd say that adults, children and infants should not be having large amounts of soy products. In addition, infants and children should not be exposed to soy more than occasionally due to the documentation of growth and hormone changes. Although, occasional soy intake for adults, and maybe children, should not be of worry. Good site though. Very informative.
written by S Krishnan, Jun 18 2012
I would like yo know more about SOY
written by Jasmine, Apr 01 2012
I've been reading so many articles on health and nutrition lately and I have to admit I'm very confused and frustrated.
People believe fruit is really healthy for humans but research on fructose suggests otherwise. People think quinoa is a supergrain but apparently that has negative qualities too. Soy has always been considered a healthier alternative to cows milk but according to this site and others, soy is not such a healthy thing.
I know everyone's genetic makeup is different.. so I guess everyone's diet should be too.
It's just a shame that there is so much information out there that is conflicting. Apparently raw vegetables are the only safe things to eat.
(I'm awaiting the responses from people telling me how unsafe vegetables are)
written by dr rob peers, Mar 21 2012
i'll have to study your references more closely, but may i say, for openers, that the okinawan centenarians eat soy products all their life, and seem not to get any specific diseases--in fact, they seem quite unusually energetic (phytic acid activates anti-ageing genes, including the master energy gene pgc1-alpha)--see the video on the home page of [okinawa diet--official site] and watch the relay race runners, and the bouncy tai-chi oldsters---amazing

having said that, i will go and study your anti-soy stuff, which obviously deserves analysis-----cheers, dr rob
written by Louise, Jan 26 2012
@Danny, that's great, but probably best to use another age group to compare yourself too, most 20 year olds I know are not that sharp...just sayin.
written by Professor , Jan 12 2012
This research is laughable! So sad that the general public doesn't understand the difference between substantial, and gold standard studies such as clinical studies done on human beings, not on animals; any true researcher knows that researching on animals to draw conclusions to human metabolism is NOT considered credible outcomes. Also, your research lacks looking at populations as a whole, not a few subjects at at time. Also, maybe your research should look at studies that include the entire soy food (not just raw meal or isolates) in normal amounts of intake (such as 1.5 grams per day of a intact soy food vs. 96.4 g/1000 kcal's of protein soy isolate which would be impossible for a human being to consume eating foods such as tofu/soy milk/tempeh, etc. This is propaganda and very misleading information.
written by Enlightened, Jan 01 2011
Look maybe it has to do with your genetic make up. I've just recenty learned that soy has caused my thyroid to malfunction and as a result my hormones are messed up too. I've been experiencing anemia and hypoglycemia for no apparent reason and have been labled "healthy" in spite of the symptoms. Thank God I'm now at a doctor that is treating my thyroid and hormones and put me on a soy free diet. And poof! No hypoglycemia or anemia anymore. Go figure. We're not crazy. We're just saying that there is something very real we are experienceing that is made better by avoiding soy. If you have not experienced an issue with it, then maybe you are genetically different than me. is in all junk and fast food. I'ts in just about everything made by man.
written by EM, Oct 20 2011
My biggest allergy and my son's is Soy. Why do they worry about peanuts (another big allergy/legumes) and yet the FDA allows the food industry to push soy into everything. My stomach hurts every time I eat it like an ulcer. Same with aspertame. So what is a person to eat that is high protein and low fat that doesn't have artificial sugar.
written by Carmela, Sep 26 2011
I have a hard time finding ANYTHING that does not have some kind of soy in it! I found out I feel sick every time I eat it! I know when it is in food, and this economy makes it a cheap oil to put in everything, so I started making everything with coconut oil, I feel a lot better!smilies/smiley.gif
written by greggarious, Jul 04 2011
Soybeans were originally planted to improve soil fertility (nitrogen fixation), not as food. Fermentation, as in miso and tempeh, makes it better as a food, but still not optimum. Despite some protein, soy has protein uptake inhibitors, disrupting protein metabolism, and phyto-estrogens, plant hormones that disrupt endocrine function. All well-documented, all true. I believe unfermented soy products like tofu may be by-products of other soy-based products, like ink and solvents, cleverly market as healthy, to turn waste-products into questionable commodities. Soy alert!
written by G, Jun 16 2011
Checking the fda website as listed in the pdf - more hits are retrieved by typing in "corn" (342 references)than results from "soy" (196). Close behind are such plants as: onions (18smilies/cool.gif, wheat (181), oats (13smilies/cool.gif and carrots (116). Guess we should avoid those too?
written by BJ, Mar 24 2011
Don't think a bit soy based food can hurt. Better than the Junk food of nowadays Now that causes harm, including ED and that's no joke!
written by danny, Jan 29 2011
it's all bullshit. I'm a vegan and a third of what I eat is in one form or another soy. I'm 73 and fit and sharp as a 20 year old.

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Last Updated on Tuesday, 08 May 2012 15:11