This is Dr. Dahlman’s published article in Today’s Chiropractic March/April 2005 issue. A response to a ridiculously biased and incorrect article from the previous issue in the same magazine.
To My Website Readers: The November/December 2004 issue of Today’s Chiropractic contained an article that relentlessly attacked soy and created the incorrect perception that it’s not good for you. A perspective highly promoted by the Weston A. Price Foundation. I decided to research the studies that were used to substantiate this perspective and found that they were either all flawed or misinterpreted simply to support the author’s point of view. In addition, in doing the research, I found a basic cottage industry denouncing soy as a healthy food and amazingly, they all relied on the same flawed and misinterpreted studies. The original article follows my response that appeared in the March/April 2005 issue.
By Dr. David Dahlman, DC ©2005
The anti-soy bias has grown to a fever pitch. Embraced by numerous authors writing almost carbon copy essays and misinterpreting the same flawed studies, an unbiased review of those studies along with others, reveals a much different perspective. An example of misinterpreting a study is the linking of soy to rickets by citing a 1919 study by Mellanby using dogs and failing to note they were raised exclusively indoors in the absence of sunlight or ultraviolet light.1 Another is to link soy to goiters and fail to mention the researchers purposely eliminated iodine from the diet or severely restricted it.2 And that’s just the beginning.
There are many forms of soy consumed throughout the world such as raw soybeans, steamed (edamame), soy milk, tofu, soy oil, soy lecithin, soy meal, soy flour, soy protein concentrates (70% protein), soy protein isolates (90-95% protein), fermented soy (tempeh, tamari, natto, miso) and the active ingredients called isoflavones, the most common: genistein and daidzein. Most of the critics are in agreement that the dangers of soy revolve around the unfermented types and isoflavones of soy, without regard to the growing body of emerging data suggesting that intestinal microflora ferment unfermented soy and also affect isoflavone absorption and metabolism.3
Historically, soy foods have been an integral part of the Asian diet. This large body of accumulated epidemiological data has not shown that soy consumption poses any substantial risk to human health. The anti-soy faction are sure that soy is not a complete protein, prevents mineral absorption and the action of digestive enzymes, causes rickets, cancer, goiter and lowers thyroid hormones and is responsible for the breakdown of muscle. Let’s take a look at each of these and other claims.
Complete Protein
One controversy revolves around the completeness of soy as a protein. The old method of evaluating protein quality know as the protein efficiency ratio (PER) was based on the response of growing rats to a particular protein source. Due to different protein needs for humans compared to rats, early studies using PER values suggested soy was not a complete protein. Updated methods for determining protein quality known as the Protein Digestibility Corrected Amino Acid Score (PDCAAS) adopted by the FDA and World Health Organization show soy having the same score as egg white and milk protein.4,5,6,7
Mineral Absorption
Soy products provide a balance of nutrients including minerals and their bioavailability depends on the form of the soy product and whether fiber and/or phytic acid (inositol hexaphosphate) is present. Phytic acid can bind minerals in the gastrointestinal tract. In diets where soy represents a small percentage of total calories, other mineral rich foods contribute to offset this issue. In diets high in soy, removal of phytic acid increases mineral bioavailability and cooking partially destroys phytic acid and again, as long as used in a well balanced diet, creates no health concern.
Inhibition of Digestive Enzymes
Raw soybeans contain a family of protease inhibitors that can bind to trypsin and other proteolytic digestive enzymes and inhibit their action. As with other protease inhibitors, they can be destroyed by heat increasing the digestibility of soy.4 This is not unique to soy, protease inhibitors are ubiquitous in food. Raw soy flour has only half as much trypsin protease inhibitor activity as raw potato and a similar amount to raw egg. Animal studies suggest that protease inhibitors may cause pancreatic cancer, however there is no direct evidence of low levels being harmful to humans.4 In fact, recent studies have suggested protease inhibitors may be anti-cancer agents.8
Thyroid
In addition to the misinterpreted study previously mentioned in the first paragraph that purposely restricted iodine, there have been additional in vitro and animal studies that link soy intake to inhibition of thyroid peroxidase, lowered thyroid hormones and goiter.
Though Divi, Chang and Doerge believe they had found a link to goiter in 1996 and 1997,9,10 a subsequent study by Chang and Doerge in 2000 found cases of goiter only in those predisposed or consuming diets lacking in iodine. They also found that genistein can deactivate thyroid peroxidase with no accompanying effect on thyroid hormones.11 In fact, the University of Minnesota recently found that the consumption of isoflavone-rich soy protein, at levels that were as much as 3-4 times the isoflavone intake in Japan, had little effect on thyroid hormone levels in either pre- or postmenopausal women over a three-month period.12,13
In addition, a recently conducted double-blind study six months in duration, that involved 38 postmenopausal women who were not on hormone therapy, found no differences in thyroid function, based on measures of thyroid stimulating hormone (TSH), total T4 and T3, between subjects given daily either a placebo or a soybean isoflavone extract that provided 90 mg (equal to approximately three servings of soy) of isoflavones.14
Improper conclusions have also been drawn from a New York Times article in 1996 discussing 100 million cases of goiter in China.15 Goiter occurs in inland areas of all continents because of diets insufficient in iodine compared to costal areas that utilize fish and seaweed which are iodine rich. In contrast, developed countries have better food distribution and most salt is iodized specifically to prevent goiter.
Rickets
In the often misquoted study mentioned in the first paragraph of dogs housed in the absence of sunlight and fed one of four cereal diets, Mellanby in 1919 clearly established the role of diet in the cause of rickets, but not because of soy. Mellanby soon established that all four of his diets were relatively deficient in calcium and lacked favorable calcium/phosphorus ratios.16 Interestingly, it was his work that led to McCollum’s later discovery of Vitamin D and its deficiency as being the cause of rickets.16 Vitamin D and it’s connection to calcium and bone metabolism is now well established. It should also be noted that neither Mellanby nor McCollum ever suggested soy as the cause of rickets.
Cancer and Hormone Levels
Critics once again connect the unconnected in order to place blame on soy. Asian and Japanese populations do have higher rates of esophageal, stomach, liver and pancreatic cancer. It is a leap of logic to conclude that soy is the only responsible variable.22
Epidemiological evidence shows the responsibility for some of these cancers may well be a lack of refrigeration in the rural areas of these countries as well as the consumption of much smoked or barbecued meat. Liver cancer rates may be more specifically linked to higher rates of Hepatitis B and the presence of alflatoxins in the food supply. Clearly, there are many variables potentially responsible for high cancer rates, not just soy.
Specific hormone related cancers (breast and prostate) are low in Asia and may be linked to early intake of soy.23 It is hypothesized that isoflavones weakly bind to estrogen receptors and block estrogen from the receptors or they inhibit enzymes that promote cancer cell growth.23
Soy contains many anti-cancer agents such as isoflavones, protease inhibitors, phytic acid and phytosterols (beta-sitosterols). Saponins as well, possibly due to their anti-oxidant activity and/or ability to regulate cellular proliferation are anticarcinogenic.8
One fact should be made clear. There is no estrogen in soy! The term “phytoestogen”confuses people. A more accurate term may be “estrogen-like phytoadaptogen”. Unlike estrogens which are uniformly agonists and anti-estrogens which are uniformly antagonists, adaptogens will enhance or suppress activity depending on the physiological needs of the tissue. This response is discussed in the literature as selective estrogen response modifiers (SERMs). Most notable SERMs are tamoxifen for breast cancer reduction and raloxifene to improve bone mass.24,25 Many natural “SERMs”also exist.
Claims by critics of soy that the “amount of phytoestrogens that are in a day’s worth of soy infant formula equal 5 days of birth control pills”loses its impact when the preferential tissue response of adaptogens is better understood accompanied by the realization there is no estrogen in any soy product.
It is well documented that a low lifetime exposure to estrogen reduces the risk of breast and prostate cancer. Recent research has taken a closer look at specific estrogen metabolites, 16-alpha hydroxy-estradiol and 4-hydroxy-estradiol and determined they are genotoxic. Soy isoflavones may shift estrogen metabolism towards the production of more beneficial metabolites such as 2- hydroxy-estradiol and improve the 2:16 ratio.26,27
A word of caution for estrogen receptor positive breast cancer patients. There is no conclusive evidence that isoflavones are harmless or harmful under this circumstance.18 Unfortunate misinterpretation by critics cite a study by Dees et al. claiming that genistein causes breast cancer cell proliferation.28 This was an in vitro study testing whether genistein would prevent breast cancer cell growth (an anti-estrogen) in the presence of DDT. The study found genistein unable to offset the effects of DDT. Logic suggests that if it shifts estrogen metabolism to help eliminate the genotoxic forms of metabolites, it may be beneficial for the treatment of breast cancer.
In men, studies report there are no adverse effects from soy consumption on sperm quality though there may be small effects on sex hormone-binding globulin and steroid hormones.28 Many studies show that soy consumption may reduce prostate cancer risk.30-36
Multiple studies also suggest soy will reduce hot flashes and vasomotor symptoms in women using soy foods, soy protein isolate and soy extracts (40-80 mg. isoflavones per day).37,38,39 Bone health is also reported improved as isoflavones promote bone conservation by stimulating osteoblastic bone formation and inhibiting osteoclastic bone breakdown. Specific mechanism is believed to be related to the adaptogenic properties already discussed with regard to estrogen.40,41,42
Muscle Protein Breakdown
Critics warn athletes who use a soy based protein powder that they may actually be breaking down muscle instead of building it. In citing a study with pigs fed either a casein based or soy based diet, researchers claim the soy based diet resulted in muscle breakdown as opposed to the casein based diet. The critics fail to reveal the researchers say in the study they supplemented the casein fed pigs with methionine, threonine and tryptophan.43 Regardless, no human eats a diet of 100% soy or casein.
Cardiovascular Disease
In 1999, the FDA approved a health claim for soy protein and it’s effect on lowering cholesterol saying, “Diets low in saturated fat and cholesterol that include 25 grams of soy protein a day may reduce the risk of heart disease”.17 This health claim was approved only after an extensive, yearlong review of the studies.18
In numerous controlled human clinical trials, Anderson, et al. found that soy consumption rather than animal protein significantly decreased serum concentrations of total cholesterol, LDL and triglycerides in hypercholesterolemic individuals, but not in normolipidemic individuals.19,20,21
Other Concerns
A by-product of high temperature or alkaline processing is lysinoalanine. Critics of soy remind us that it is a toxin without also mentioning that it is also found in milk or any other processed protein. Milder processing techniques since the mid 1980’s have resulted in “dramatic decreases”of lysinoalanine in processed foods.44 Additionally, stainless steel processing tanks have replaced aluminum tanks leaving only naturally occuring aluminum in soy protein isolates.
Another complaint is the presence of hemagglutinin, a clot promoting substance proven in vitro, not in vivo where other human biochemistry and nutritional factors would negate its influence.
Studies have shown a greater incidence of insulin- dependent diabetes mellitus in children who consumed soy infant formula.45 Considering that some companies producing poor quality products will add free glutamic acid (monosodium glutamate aka MSG) and/or aspartic acid to their formulas, there is no argument that this is a product that children should avoid.
Another concern for consumers is the growing trend toward genetically modified crops including soy. Genetic modification of foods will have yet unknown long term consequences. Buying products marked “Non GM”or “Non GMO”is the safe way to avoid them.
In Summary
The most commonly quoted studies seem to be interpreted simply to advance the argument rather than to understand it. Reading of the titles or only the discussion portion of the studies by the soy critics ignore the internal design of the study and have lead to wrong conclusions. Common sense will find that one thing is certain. Rarely will you find billions of people embracing a food for centuries only to find they have been wrong.
1. Mellanby E. An experimental investigation on rickets. Lancet.1919; 1 :407 – 412
2. Drane, H.M. et al., “Oestrogenic Activity of Soya-Bean Products”, Food, Cosmetics and Technology (1980) 18:425-427.
3. Messina M, Erdman J Jr, Setchell KD. Introduction to and Perspectives from the Fifth International Symposium on the Role of Soy in Preventing and Treating Chronic Disease. J Nutr 004;134(5):1205S-06S.
4. Erdman JW Jr, Fordyce EJ. Soy products and the human diet. Am J Clin Nutr 1989;49(5):725-37
5. Sarwar G, McDonough FE. Evaluation of protein digestibility-corrected amino acid score method for assessing protein quality of foods. J Assoc Off Anal Chem 1990;73(3):346-56
6. FAO/WHO/UNU Expert Consultation. Energy and Protein Requirements. Geneva: World Health Organization;1985 (WHO techncal report, series 724)
7. U.S. Food and Drug Administration. Federal Register. 21 CFR, Part 101, et al. Part III. Food Labeling 1991
8. Kennedy AR. The evidence for soybean products as cancer preventative agents. J Nutr1995;125(3 Suppl):733S-43S
9. Divi RL, Chang HC, Doerge DR. Anti-thyroid isoflavones from soybean: isolation, characterization, and mechanisms of action. Biochem Pharmacol 1997; 54:1087-96.
10. Divi RL, Doerge DR. Inhibition of thyroid peroxidase by dietary flavonoids. Chem Res Toxicol 1996;9:16-23.
11. Chang HC, Doerge DR. Dietary genistein inactivates rat thyroid peroxidase in vivo without an apparent hypothyroid effect. Toxicol Appl Pharmacol 2000; 168:244-52.
12. Duncan AM, Merz BE, Xu X, Nagel TC, Phipps WR, Kurzer MS. Soy isoflavones exert modest hormonal effects in premenopausal women. J Clin Endocrinol Metab 1999; 84:192-7.
13. Duncan AM, Underhill KE, Xu X, Lavalleur J, Phipps WR, Kurzer MS. Modest hormonal effects of soy isoflavones in postmenopausal women [published erratum appears in J Clin Endocrinol Metab 2000 Jan;85(1):448]. J Clin Endocrinol Metab 1999; 84:3479-84.
14. Bruce B, Spiller GA, Holloway L. Soy isoflavones do not have an antithyroid effect in postmenopausal women over 64 years of age. FASEB J 2000; 11:193.
15. New York Times, June 6, 1996.
16. McCollum EV. A History of Nutrition. Cambridge, MA: Riverside Press; 1957.
17. U.S. Food and Drug Administration. Food labeling: health claims; soy protein and coronary heart disease. Fed Regist 1998;63(217):62997-63015.
18. Henkel J. U.S. Food and Drug Administration. Soy: Health Claims for soy protein, questions about other components. Available at: www.fda.gov/fdac/features/2000/300_soy.html.
19. Anderson JW, Johnstone BM,Cook-Newell ME. Meta-analysis of the effects of soy protein intake on serum lipids. N Eng J Med 1995;333(5):276-82.
20. Potter SM. Overview of the proposed mechanisms for the hypocholesterolemic effect of soy. J Nutr1995;125(3 Suppl):600S-11S.
21. Potter SM, Baum JA, Teng H, Stillman RJ, Shay NF, Erdman JW Jr. Soy protein and Isoflavones: their effects on blood lipids and bone density in post menopausal women. Am J Clin Nutr1998;68 (6 Suppl):1375S-79S.
22. Harras, A (ed.), Cancer Rates and Risks, National Institutes of Health, National Cancer Institute, 1996, 4th Edition.
23. Shu XO, Jin F, Dai Q, et al. Soyfood intake during adolescence and subsequent risk of breast cancer among Chinese women. Cancer Epidemiol Biomarkers Prev 2001;10(5):483-88
24. Riggs BL, Hartmann LC. Selective estrogen-receptor modifiers-mechanisms of action and application to clinical practice. N Eng J Med. 2003;348(7):618-29.
25. Katznellenbogen BS, Choi I, Delage-Mourroux R. Molecilar mechanisms of estrogen action: selective ligands and receptor pharmacology. J Steroid Biochem Mol Biol. 2000;74:279-85.
26. Xu X, Duncan Am, Merz BE, Kurzer MS. Effects of soy isoflavone on estrogen and phytoestrogen metabolism in premenopausal women. Cancer Epidemiol Biomarkers Prev 1998;7(12):1101-08.
27. Xu X, Duncan AM, Wangen KE, Kurzer MS. Soy consumption alters endogenous metabolism in postmenopausal women. Cancer Epidemiol Biomarkers Prev 2000;9(8):781-86.
28. Dees C., et al. Dietary estrogens stimulate human breast cells to enter the cell cycle. Environmental Health Perspectives 1997;105(Suppl. 3):633-636.
29. Persky VW, Turyk ME, Wang L et al. Effect of soy protein on endogenous hormones in post menopausal women. Am J Clin Nutr 2002;75(1):145-53.
30. Peterson G, Barnes S.Genistein and biochanin A inhibit the growth of human prostate cancer cells but not epidermal growth factor receptor tyrosine autophosphorylation. Prostate 1993;22(4):335-45. 31. Geller J, Sionit L, Partido C, et al. Genistein inhibits the growth of human-patient BPH and prostate cancer in histoculture. The Prostate. 1998; 34:75-79.
32. Barnes S. Effect of genistein on in vitro and in vivo models of cancer. J Nutr. 1995; 125:777S-783S.
33. Adlercreutz CH, Goldin BR, Gorbach SL et al. Soybean phytoestrogen intake and cancer risk. J Nutr. 1995 Mar;125(3 Suppl):757S-770S.
34. Nagata C, Takatsuka N, Inaba S, et al. Effect of soymilk consumption on serum estrogen concentrations in premenopausal Japanese women. J Natl Cancer Inst 1998;90:1830- 5.
35. Habito RC, Montalto J, Leslie E, Ball M.J. Effects of replacing meat with soyabean in the diet on sex hormone concentrations in healthy adult males. Br J Nutr, October 2000, vol. 84, no. 4, pp. 557-563(7)
36. Mitchell JH, Cawood E, Kinniburgh D, Provan A, Collins AR, Irvine DS. Effect of a phyto-estrogen food supplement on reproductive health in normal males. Clin Sci 2001 Jun;100(6):613-8.
37. The role of isoflavones in menopausal health: consensus opinion of The North American Menopause Society . Menopause 2000 Jul-Aug;7(4):215-29.
38. Eden J. Phytoestrogens and the menopause. Baillieres clin Endocrinol Metab 1998;12(4):581-87.
39. Dallas FS, Rice GE, Wahlqvist ML, et al. Effects of dietary phytoestrogens in post menopausal women. Climacteric 1998;1(2):124-29.
40. Brynin R. Soy and its isoflavones: a review of their effects on bone density. Altern Med Rev 2002;7(4):317-27.
41. Migliaccio S, Anderson JJ. Isoflavones and skeletal health: are these molecules ready for clinical application? Osteoporos Int. 2003 Jun;14(5):361-8.
42. Setchell KD, Lydeking-Olsen E. Dietary phytoestrogens and their effect on bone: evidence from in vitro and in vivo, human observational, and dietary intervention studies. Am J Clin Nutr. 2003;78(3 Suppl):593S-609S.
43. Lohrke, B. “Activation of Skeletal Muscle Protein Breakdown Following Consumption of Soybean Protein in Pigs,”Br J Nutr, 2001 Apr; 85 (4): 447-57.
44. Boschin G, D’Agostina A, Rinaldi A, Arnoldi A. Lysinoalanine Content of Formulas for Enteral Nutrition 2003. J. Dairy Sci. 86:2283- 2287
45. Fort P, Lanes R, Dahlem, S, Recker, B, Weyman-Daum, M, Pugliese, M, Lifshitz, FJ, “Breast-feeding and insulin-dependent diabetes mellitus in children,”Am Coll Nutr 1986; 5(5): 439-41.
Here is the original article that generated my article:
Dispelling the “Joy of Soy” Myth
By Raquel Martin
A few decades ago, soybeans were not used as a food but were used instead, and more appropriately, in crop rotation. However, the discovery of long periods of fermentation has been found to be essential in transferring soy into a healthy food. This process significantly reduces the phytate content of soybeans, as well as the trypsin inhibitors that interfere with many vital enzymes and amino acids. Fortunately, fermented soy such as tempeh, miso, natto, tamari and other fermented soy products can provide nourishment that is easily assimilated.
When precipitated soy products like tofu are consumed with meat, the mineral-blocking effects of the phytates are reduced.i However, when consuming soy (tofu/bean curds) as a replacement for meat and dairy products, mineral deficiencies occur. Such a diet can lead to an amino acid deficiency.ii “Asian and Western children, who do not get enough meat and fish products to counteract the effects of a high phytate diet, are subject to rickets, and other growth problems.”iii Contrary to popular opinion concerning the healthy effect of consuming soy food has on Asians, a New York Times article (June 6, 1996) cited 100 million cases of goiters at present in China.
We are told that soybeans are high in protein, but what we are not told is that soybeans also block the action of the enzymes that are essential in digestion of protein. Soy damages the enzymes that manufacture thyroid hormones, as well as those enzymes essential to proper thyroid functioning.iv v Besides this bad news, scientists have known for years that isoflavones in soy products can cause enlarged thyroid glands (goiter)vi.
How are soy protein isolates (S.P.I) made? They are manufactured by mixing an alkaline solution to it in order to remove fiber. A toxin called lysinoalanine is formed during alkaline processing.vii Then it is separated by adding an acid. This is done in aluminum tanks, which leach high levels of aluminum into the final product. It is then spray-dried at high temperatures to make a protein powder. Nitrites, which are potent carcinogens, are formed during spray drying. A final indignity to this substance is brought on by the use of additional high-temperature and pressure. This is what produces textured soy protein. However when the soy is denatured in this way, the resulting product becomes ineffective.viii And even though much of the trypsin inhibitor content can be removed through high-temperature processing, it’s note all removed during this processing. This remnant can vary as much as fivefold.ix
This leftover anti-nutrient (a toxin) becomes more of a concern when MSG is added in order to mask the unpleasant taste of this texturized soy product. This in turn often creates more allergic reactions as well as a need to increase vitamins E, K, D, B12, calcium, magnesium, manganese, molybdenum, copper, iron and of course, zinc.x The effect of mineral blocking enzyme inhibitors in soy can result in any number of conditions, such as endocrine disruption (goiters), reproductive disorders and allergic reactions.xi
Test animals fed soy protein isolates (SPI) develop enlarged thyroid, as well as the enlargement of other glands, most particularly the pancreas. Their diets, which are high in trypsin inhibitors, are also subjected to pathological conditions of the pancreas, including cancer.xii A biochemical pharmacology study confirms that fatigue, as well as goiter problems, are associated with soy food.xiii
The National Center for Toxicological Research reports that soy isoflavones (genistein and daidzein) “inhibit thyroid peroxidase-catalyzed reactions essential to thyroid hormone synthesis.”xiv Japanese researchers studied the effects of consuming as little as two tablespoons of soybean a day. Even when healthy people were put on this diet for a short period of time suppressed thyroid function and goiters developed, “especially elderly subjects.”xv Infants have also been found to suffer from hypothyroid problem when on a soybean diet.xvi Another study confirms that autoimmune thyroid disease is linked to children who have consumed soymilk formula on a regular basis.xvii Doctors should be aware of the “potential interaction between soy infant formula and thyroid function,”xviii says the New Zealand Ministry of Health.
And a study comparing consumption of soy formula in non-diabetic children found those who drank it, as infants were prone to diabetes.xix Also, it is possible that allergies, so prevalent these days, may have been exacerbated from consuming soy formula. For instance, “the amount of phytoestrogens that are in a day’s worth of soy infant formula equals 5 birth control pills,”says Mary G. Enig, Ph.D., president of the Maryland Nutritionists Association. Nutritional experts believe that this high amount of phytoestrogens can be linked with early puberty in girls and hinders physical maturation in boys.xx In 1998, the FDA had even received warnings from the British Government’s final account on phytoestrogens, about their harmful reactions.xxi But for reasons beyond the consumer’s knowledge FDA bureaucrats have engaged in a “rigorous approval process”for S.P.I. However, we can now protect ourselves by learning more about what’s behind all these inconsistent reports as we become more aware of the health industry’s claims and political propaganda concerning food supplements.
Soy phytates reduce zinc and iron absorption. This is a concern because numerous people, who are taking iron supplements due to low levels of this mineral, are not realizing the cause of their iron deficiency. Soybeans have one of the highest phytate levels of any grain or legume that has been studied,xxii and even long periods of cooking at high temperatures will not completely eliminate the phytate levels.xxiii Phytates (an organic acid found within the outer portion of all seeds) block the absorption of essential minerals (e.g. calcium, magnesium, iron, and especially zinc. This is a concern because high levels of zinc are needed in the brain, especially the hippocampus. Zinc plays an important role in the transmission of the nerve impulse between brain cells. Deficiency in zinc can be serious, as it’s needed in the development of brain, immune and nervous system functioning. It also plays a role in collagen formation and protein synthesis, as well as our blood-sugar control mechanism and other systems in the body.
The U.S. Department of Agriculture, Agricultural Research Service, Food & Nutrition Research Briefs (July 1997) provides information showing how changes in zinc intake can affect cognitive function.xxiv This suggests the importance of zinc in the pathological functioning of the cerebral cortex.xxv Furthermore, age-related zinc deficiency in cells may contribute to brain cell death in Alzheimer’s dementia.xxvi
Congenital abnormalities in an infant’s nervous system can be caused by a deficiency of zinc during pregnancy and lactation. In children, “insufficient levels of zinc have been associated with lowered learning ability, apathy, lethargy, and mental retardation.”xxvii The USDA references a study of 372 Chinese school children with very low levels of zinc in their bodies. The children who received zinc supplements had the most improved performance�”especially in perception, memory, reasoning, and psychomotor skills such as eye-hand coordination. “Both phytate and soy protein reduce iron absorption so that the iron in soy foods is generally poorly absorbed.”xxviii
As early as 1967, researchers found soy formula to have a negative effect on zinc absorption and also a strong correlation between phytate content and poor growth. Author Sally Fallon warns “a reduced rate of growth is especially serious in the infant as it causes a delay in the accumulation of lipids in the myelin, and hence jeopardizes the development of the brain and nervous system.”xxix It has even been found to increase the deposition of fatty acids in the liver.xxx
Soy and Cancer
The promotional health claims about soy products that come from vitamin/food manufacturer’s ads and multi-level marketers is then passed on to medical doctors, as well as the media and are received as gospel truth. Is this how we, the consumer, want to obtain information that will affect our future health? Some of the hype about soy alleges to aid in weight loss, protect the heart, prevent female discomforts and the list goes on. One piece of literature from a vitamin company goes so far as to state that the “Japanese, who eat 30 times as much soy as North Americans, have a lower incidence of cancers of the breast, uterus and prostate.”xxxi I have not found clinical studies to back this up and if it is true, it should also be pointed out that these Asians and Japanese have a higher rate of other kinds of cancer (esophagus, stomach, pancreas and liver).xxxii xxxiii Other literature confirms that a high rate of thyroid cancer is linked to soy consumption.xxxiv
In a 1996 study, researchers discovered that women who consumed the soy protein isolates had a greater risk of experiencing abnormally excessive cell growth, a symptom that can be a predecessor to malignancies.xxxv A study called “Dietary Estrogens Stimulate Human Breast Cells to Enter the Cell Cycle,”led researchers to conclude that women should not consume soy products, thinking that they were preventing breast cancer, when in fact dietary genistein found in soy food actually stimulates breast cell growth xxxvi In fact, according to Cancer Research “Genistein…is more carcinogenic than DES.”xxxvii That’s right DES the drug that caused death and disfigurement for countless women.
Additionally, it takes a mere 45 mg of isoflavones in premenopausal women to create a biological effect that will cause a reduction in hormones needed for proper thyroid activity. Numerous women are on thyroid medication, yet at the same time they are increasing their soy intake. The two seem to be defeating each other’s purposes. Other problems concerning a diet rich in soy food are highlighted from animal studies at Brigham Young University’s Neuroscience Center. Researchers found that consumption of phytoestrogens from soy for a relatively short interval can significantly elevate estrogen levels in the brain and can interfere with and thus decrease calcium-binding proteins in the brain.xxxviii
Athletes should be aware that the “soy protein”drinks they are consuming in order to build muscle tissue, may actually cause muscle protein breakdown.xxxix Take a look at some of the studies, such as the British Journal of Nutrition, which correlates strongly to weight-training athletes, whose diets consist of inferior soy protein, which may increase protein breakdown in skeletal muscle. Soybean protein isolates were given to pigs for fifteen weeks. Cortisol levels began to rise after their morning meal. Soy meals were causing the body to break down muscle protein in order for it to get its required amino acids.xl
This soy fad is resulting in numerous physiological abnormalities. Shocking news on this subject comes from investigations made by toxicologist, Mike Fitzpatrick, Ph.D., who confirms the facts that soy consumption has been linked to disorders, such as infertility and leukemia, and that soy foods are highly estrogenic. In 1992, the Swiss health service estimated that 299 grams of soy protein provided the estrogenic equivalent of the Pill.xli In fact other studies suggest that isoflavones inhibit synthesis of estradiol and other steroid hormones as well.xlii xliii But soy food can be very disruptive as their isoflavones, genistein and diadzen, can create endocrine dysfunction.
Elaine Hollingsworth in her book Take Control of Your Health and Escape the Sickness Industry says, “Soybeans contain Hemagglutinin, a clot-promoting substance that causes red blood cells to clump together. These clustered blood cells are unable to properly absorb oxygen for distribution to the body’s tissues, which can damage the heart.”xliv In his classic book, A Cancer Therapy – Results of 50 Cases, (p. 237) Dr. Charlotte Gerson warns to stay away from soy products. “Genistein, a component of soy, is more carcinogenic than DES.”xlv
Hollingsworth says: “Increased level of tofu consumption was found to be associated with indications of brain atrophy and cognitive impairment in later life. They even found, at autopsy, swelling of the brain cavities and a decrease in brain weight among heavy tofu eaters.xlvi “Few people are aware that most soil contains aluminium. It is one of the most prevalent minerals, but it doesn’t affect most crops. Soy, however, has an affinity for aluminium and extracts it from the soil and concentrates it in the beans. This contamination is exacerbated by the aluminium tanks, which are used in the acid wash soy, is subjected to. So, when you ingest soy in any form, you also ingest aluminium, known for causing many health problems.”xlvii
It seems like we, the consumer, have been duped by the producers and their ad campaigns regarding the so-called “health”benefits obtained from soy products. Dr. Joseph Mercola tells us that the propaganda, from so many sources in the industry, has spread like a wild fire; and that this aggressive publicity is just another “nail in the coffin…”concerning a food that is not “designed to be eaten.”xlviii Never has there been a mention of the many studies that demonstrate the toxicity to our thyroid, liver or endocrine glands.xlix
Portions of this article have been excerpted from The Estrogen Alternative and Preventing Arthritis naturally: The Untold Story by Raquel Martin. (Healing Arts Press, 2004)
i Sandstrom, B. et al., “Effect of protein level and protein source on zinc absorption in humans”, Journal of Nutrition 119(1): 48-53, January 1989; Tait, Susan et al., “The availability of minerals in food, with particular reference to iron”, Journal of Research in Society and Health 103(2): 74-77, April 1983.
ii Enig MG, Fallon SA, Tragedy and Hype, The Third International Soy Symposium. Nexus Magazine, Vol. 7, No. 3, April-May 2000.
iii Martin, R., Gerstung, J, The Estrogen Alternative: Natural Hormone Therapy with Botanical Progesterone (Foreword by John Hart, M.D.) (4th Ed. 2004 in print) Healing Arts Press, Rochester, Vt. Citing: Mellanby, Edward, “Experimental rickets: The effect of cereals and their interaction with other factors of diet and environment in producing rickets”, Journal of the Medical Research Council 93:265, March 1925; Wills, M.R. et al., “Phytic Acid and Nutritional Rickets in Immigrants”, The Lancet, April 8,1972, pp. 771-773.
iv Ishizuki, Y. et al., “The Effects on the Thyroid Gland of Soybeans Administered Experimentally in Healthy Subjects”, Nippon Naibunpi Gakkai Zasshi (1991) 767:622-629.
v Doerge, Daniel R., “Inactivation of Thyroid Peroxidase by Genistein and Daidzein in Vitro and in Vivo; Mechanism for Anti-Thyroid Activity of Soy”, presented at the November 1999 Soy Symposium in Washington, DC, National Center for Toxicological Research, Jefferson, AR 72029, USA.
viDrane, H.M. et al., “Oestrogenic Activity of Soya-Bean Products”, Food, Cosmetics and Technology (1980) 18:425-427.
vii Rackis et al., ibid., p. 22; Rackis, et al., “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), USA, Contract No. FDA 223-75-2004, 1979.
viii Wallace, G.M., “Studies on the Processing and Properties of Soymilk”, Journal of Science and Food Agriculture, 22:526-535, October 1971.
ix Rackis et al., ibid
x Rackis, Joseph, J., “Biological and Physiological Factors in Soybeans”, Journal of the American Oil Chemists’ Society, 51:161A-170A, January 1974.
xi “Food Labeling: Health Claims: Soy Protein and Coronary Heart Disease,”Food and Drug Administration 21 CFR, Part 101 (Docket No. 98P-0683).
xii Rackis, Joseph J. et al., “The USDA trypsin inhibitor study. I. Background, objectives and procedural details”, Qualification of Plant Foods in Human Nutrition, vol. 35, 1985. p. 232.
xiii Martin, R., Gerstung, J, The Estrogen Alternative: Natural Hormone Therapy with Botanical Progesterone (Foreword by John Hart, M.D.) (4th Ed. 2004 in print) Healing Arts Press, Rochester, Vt. Citing: Divi, RL, Chang HC, Doerge, DR, “Anti-thyroid Isoflavones from Soybean: Isolation, Characterization, and Mechanisms of Action,”Biochem. Pharmacol., 1997 Nov 15; 54(10):1087-96.
xiv Ibid: Divi, RL, Chang HC, Doerge, DR, “Anti-thyroid Isoflavones from Soybean: Isolation, Characterization, and Mechanisms of Action,”Biochem. Pharmacol.
xv Ishizuki, Y, Hirooka, Y, Murata, Y, Togashi, K, “The Effects on the Thyroid Gland of Soybeans Administered Experimentally in Healthy Subjects,”Nippon Naibunpi Gakkai Zasshi 1991 May 20; 67(5): 622-29.
xvi Shepard TH, Soybean goiter. New Eng J Med 1960; 262:1099-1103.
xvii Fort P, Moses N, Fusion, M, Goldberg, T, Leftists, F, “Breast and Soy-Formula Feedings in Early Infancy and the Prevalence of Autoimmune Thyroid Disease in Children,”J Am Coll Nutr 1990 Apr; 9(2): 164-67.
xviii Regulatory Guidance in Other Countries: New Zealand Ministry of Health Position Statement on Soy Formulas (Adobe Acrobat file).
xix Fort P, Lanes R, Dahlem, S, Recker, B, Weyman-Daum, M, Pugliese, M, Lifshitz, FJ, “Breast-feeding and insulin-dependent diabetes mellitus in children,”Am Coll Nutr 1986; 5(5): 439-41.
xx Martin, R., Gerstung, J, The Estrogen Alternative: Natural Hormone Therapy with Botanical Progesterone (Foreword by John Hart, M.D.) (4th Ed. 2004 in print) Healing Arts Press, Rochester, Vt. Citing: “Soy Infant Formula Could Be Harmful to Infants: Groups Want it Pulled,”Nutrition Week, Dec 10, 1999; 29(46): 1-2.
xxi “IEH Assessment on Phytoestrogens in the Human Diet,”Final Report to the Ministry of Agriculture, Fisheries and Food, UK, November 1997, p. 11.
xxii El Tiney, A.H., “Proximate Composition and Mineral and Phytate Contents of Legumes Grown in Sudan”, Journal of Food Composition and Analysis (1989) 2:6778.
xxiii Ologhobo, A.D. et al., “Distribution of phosphorus and phytate in some Nigerian varieties of legumes and some effects of processing”, Journal of Food Science 49(1): 199-201, January/February 1984.
xxiv U.S. Department of Agriculture, Agricultural Research Service, Food & Nutrition Research Briefs, July 1997.
xxv Frederickson, CJ, Suh, SW, Silva, D, Frederickson, CJ, Thompson, RB, “Importance of Zinc in the Central Nervous System: The Zinc-containing Neuron,”J Nutr 2000 May; 130(5S Suppl): 1471S-83S.
xxvi Ho, LH, Ratnaike, RN, Zalewski, PD, “Involvement of Intracellular Labile Zinc in Suppression of DEVD-Caspase Activity in Human Neuroblastoma Cells,”Biochem Biophys Res Commun, 2000 Feb 5; 268(1): 148-54.
xxvii Pfeiffer CC, Braverman, E.R., “Zinc, The brain and behavior,”Biol Psychiatry, 1982 Apr; 17(4): 513-32.
xxviii Soy Nutritive Content, United Soybean Board. Enig, M. G., Fallon, S.A., “Tragedy and Hype, The Third International Soy Symposium,”Nexus Magazine Vol. 7, No 3, April-May 2000. Enig, Mary G. and Sally Fallon, “The Oiling of America”, NEXUS Magazine, December 1998-January 1999 and February-March 1999; also available at www.WestonAPrice.org.
xxix Sally Fallon, Nourishing Traditions: The Cookbook that Challenges Politically Correct Nutrition and The Diet Dictocrats, 2nd edition, New Trends Publishing, 1999.
xxx Rackis, Joseph J. et al., “The USDA trypsin inhibitor study. I. Background, objectives and procedural details”, Qualification of Plant Foods in Human Nutrition, vol. 35, 1985.
xxxi Natural Medicine News (L & H Vitamins, 32-33 47th Avenue, Long Island City, NY 11101), USA, January/February 2000, p. 8.
xxxii Harras, Angela (ed.), Cancer Rates and Risks, National Institutes of Health, National Cancer Institute, 1996, 4th edition; AND Rackis, Joseph J. et al., “The USDA trypsin inhibitor study. I. Background, Objectives and Procedural Details”, Qualification of Plant Foods in Human Nutrition, vol. 35, 1985.
xxxiii Rackis, Joseph J. et al., “The USDA trypsin inhibitor study. I. Background, objectives and procedural details”, Qualification of Plant Foods in Human Nutrition, vol. 35, 1985.
xxxiv Searle, Charles E. (ed.), Chemical Carcinogens, ACS Monograph 173, American Chemical Society, Washington, DC, 1976.
xxxv Petrakis, N.L. et al., “Stimulatory Influence of Soy Protein Isolate on Breast Secretion in Pre- and Post-Menopausal Women”, Cancer Epid. Bio. Prev. (1996) 5:785-794
xxxvi Dees, C. et al., “Dietary estrogens stimulate human breast cells to enter the cell cycle”, Environmental Health Perspectives (1997) 105(Suppl. 3): 633-636.
xxxvii Cancer Research, June 1, 2001 – 61 (11): 4325-8.
xxxviii Lephart, E.D., Thompson, J.M., Setchell, K.D., Adlercreutz H, Weber KS, Phytoestrogens decrease brain calcium-binding proteins… Brain Res., (2000 Mar) 17; 859(1): 123-31.
xxxix Martin, R., Gerstung, J, The Estrogen Alternative: Natural Hormone Therapy with Botanical Progesterone, (4th Ed.) Healing Arts Press, Rochester, Vt. (2004 in print) Citing: Lohrke, B. “Activation of Skeletal Muscle Protein Breakdown Following Consumption of Soybean Protein in Pigs,”Br J Nutr, 2001 Apr; 85 (4): 447-57.
xl Lohrke, B. “Activation of Skeletal Muscle Protein Breakdown Following Consumption of Soybean Protein in Pigs,”Br J Nutr, 2001 Apr; 85 (4): 447-57.
xli Bulletin de L’Office Fédéral de la Santé Publique, No. 28, July 20, 1992.
xlii Keung, W.M., “Dietary Oestrogenic Isoflavones are Potent Inhibitors of B-hydroxysteroid Dehydrogenase of P. Testosteronii”, Biochemical and Biophysical Research Committee (1995) 215:1137-1144.
xliii Makela, S.I. et al., “Estrogen-specific 12 B-Hydroxysteroid Oxidoreductase Type 1 (E.C. 1.1.1.62) as a Possible Target for the Action of Phytoestrogens”, PSEBM (1995) 208:51-59.
xliv Elaine Hollingsworth, “Take Control of Your Health and Escape the Sickness Industry”(6th edition) Empowerment Press International. Australia, 2000, http://www.doctorsaredangerous.com citing Charlotte Gerson, of the Gerson Cancer Clinic in the U.S.A., Gerson Healing Newsletter.
xlv (Cancer Research, June 1, 2001, 61(11): 4325-8).
xlvi Ibid: Hollingsworth, “Take Control of Your Health and Escape the Sickness Industry,”cited in Journal Of The American College Of Nutrition, April, 2000, and reprinted in Dr. William Campbell Douglass’ Second Opinion Newsletter.
xlvii Ibid: Hollingsworth, “Take Control of Your Health and Escape the Sickness Industry.”
xlviii http://www.mercola.com/fcgi/pf/2004/jan/21/soy.htm
xlix Setchell, K.D.R. et al., “Dietary oestrogens – a probable cause of infertility and liver disease in captive cheetahs”, Gastroenterology (1987) 93:225-233; Leopold, A.S., “Phytoestrogens: Adverse effects on reproduction in California Quail,”Science (1976) 191:98-100; Kimura, S. et al., “Development of Malignant Goiter by Defatted Soybean with Iodine-free Diet in Rats”, Gann. (1976) 67:763-765; Pelissero, C. et al., “Oestrogenic Effect of Dietary Soybean Meal on Vitellogenesis in Cultured Siberian Sturgeon Acipenser baeri”.
Published: 3/1/2005
