The dangers of soy are thoroughly documented in the scientific literature, which makes it hard to believe that many health and fitness communities and counselors, and most health food stores, still promote soy products as ultra-healthy foods.
Hopefully this harmful misrepresentation of soy foods will begin to change as the dangers of soy become better known.
A Summary of the Dangers of Soy
- Soybeans and soy products contain high levels of phytic acid, which inhibits assimilation of calcium, magnesium, copper, iron, and zinc.
- Soaking, sprouting, and long, slow cooking do not neutralize phytic acid.
- Diets high in phytic acid have been shown to cause growth problems in children.
- Trypsin inhibitors in soy interfere with protein digestion and may cause pancreatic disorders.
- Test animals showed stunted growth when fed trypsin inhibitors from soy.
- The plant estrogens found in soy, called phytoestrogens, disrupt endocrine function, that is, the proper functioning of the glands that produce hormones, and have the potential to cause infertility as well as to promote breast cancer in adult women.
- Hypothyroidism and thyroid cancer may be caused by soy phytoestrogens.
- Infant soy formula has been linked to autoimmune thyroid disease.
- Soy has been found to increase the body's need for vitamin B12 and vitamin D.
- Fragile soy proteins are exposed to high temperatures during processing in order to make soy protein isolate and textured vegetable protein, making them unsuitable for human digestion.
- This same process results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines. (Doesn't sound like anything anyone would want to eat, does it?)
- MSG, (also called free glutamic acid), a potent neurotoxin, is formed during soy food processing. Many soy products have extra MSG added as well. (See video on the dangers of Aspartame, MSG's chemical first cousin.)
- Soy foods contain elevated levels of toxic aluminum, which negatively effects the nervous system the kidneys and has been implicated in the onset of Alzheimer's.
- It's been found that babies given infant soy formulas have 13,000 to 22,000 times more estrogen than babies fed milk-based formulas.
- Babies fed exclusively on infant soy formula are receiving the estrogenic equivalent (based on body weight) of at least four or five birth control pills per day! You read that right. Four or five birth control pills per day! Here's the reference so you can check this out for yourself. [Irvine, C. et al., "The Potential Adverse Effects of Soybean Phytoestrogens in Infant Feeding", New Zealand Medical Journal May 24, 1995, p. 318.] By contrast, dairy-based infant formula contains almost no phytoestrogens, nor does human milk, even when the mother eats soy products. (Sally Fallon & Mary G. Enig, Ph.D.)
- There has been an increase of delayed physical maturation among boys, including lack of development of sexual organs.
- Conversely, many girls today show signs of puberty, such as breast development and pubic hair, before the age of eight, and some even before the age of three.
- Both of these abnormal conditions have been linked to the use of soy formulas as well as to exposure to "environmental estrogens" such as PCBs (polychlorinated biphenyls) and DDE (dichlorodiphenyldichloroethylene)a breakdown product of DDT.
But Don't Oriental Cultures Eat Lots of Soy?
- It seems that historically, Oriental cultures consumed mostly traditionally fermented soy products such as miso, tempeh, natto, shoyu and tamari. (Tofu is not fermented, and falls into the dangerous soy foods category.) They consumed these soy foods in small amounts, as a condiment.
- Soy foods account for only 1.5 percent of calories in the Chinese diet, researchers found. (1977 Chang KC)
- The actual soybean consumed today is not the same one used by traditional Oriental cultures.
Problems with Soy Protein Isolate
- Furthermore, modern soy foods are very different from those consumed traditionally in Asia. Most are made with soy protein isolate (SPI), which is a protein-rich powder extracted by an industrial process from the waste product of soy oil manufacturing. It is the industry's way of making a profit on a waste product. The industry spent over 30 years and billions of dollars developing SPI.
- In feeding studies, SPI caused many deficiencies in rats. That soy causes deficiencies in B12 and zinc is widely recognized, but the range of deficiencies was surprising.
- Although SPI is added to many foods, it was never granted GRAS status, meaning "Generally Recognized as Safe". The FDA only granted GRAS status to SPI for use as a binder in cardboard boxes. During the processing of soy, many additional toxins are formed, including nitrates (which are carcinogens) and a toxin called lysinoalanine. It was concerns about lysinoalanine in SPI that led the FDA to deny GRAS status for SPI as a food additive.
- In spite of all these dangers of soy protein isolate, SPI is the basic ingredient of soy infant formula. The FDA even allows a health claim for foods containing 6.25 grams SPI per serving.
The Weston Price Foundation has a list of studies carried out from 1971 to 2003 showing the adverse effects of dietary soy.
To give you an idea of how condemning these studies are, here are just a few summaries. There are over 50 more!
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 breast fed 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.
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 may be at risk from aluminium toxicity when consuming formula containing more than 300 micrograms/L.
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.
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.
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.
The FDA Had the Scientific Information about the Dangers of Soy but Chose to Ignore It
You might think that people probably just didn't know about the toxic effects of soybeans, that the food industry and the FDA must have just been misinformed about the supposed benefits, and very real dangers, of soy. Unfortunately for the FDA's credibility, this was not the case.
If you simply do a search on 'soybean' at the Poisonous Plant Database of the United States FDA's Center for Food Safety and Applied Nutrition, you can see this information yourself.
Right there in black and white you'll find 288 studies on soy, many focused on the toxic properties and effects of soybeans. It's not very easy to understand or get access to the actual studies, but it is cause for great concern that the FDA had this information and knowingly chose to ignore the dangers, just as it has done with so many other additives and pharmaceuticals.
It's tragic to think of the human suffering that could have been avoided had the FDA just been more cautious and listened to their scientific advisors.
And it's mind-boggling to think that the very federal agency whose mandate is, among other things, "to promote and protect the public health, to monitor products for continued safety after they are in use, and to help the public get the accurate, science-based information needed to improve health," could knowingly do the apparent opposite.
This is one more example that highlights the need to educate yourself by finding good sources of information to base your health and diet decisions on, rather than relying on the FDA's stamp of approval.
More Confirmation on the Dangers of Soy: Medical Conditions Possibly Attributable to Soy Consumption
- Chronic Fatigue
- Heart Arrhythmia
- Heart or Liver Disease
- Infertility/Reproductive Problems
- Irritable Bowel Syndrome
- Learning Disabilities/ADD/ADHD
- Pancreatic Disorders
- Premature or Delayed Puberty
- Rheumatoid Arthritis
- Thyroid Conditions:
- Auto-Immune Thyroid Disorders (Graves' or Hashimoto's Disease)
- Thyroid Nodules
- Thyroid Cancer
- Other thyroid disorders
- Uterine Cancer
- Weight Gain
- Always feeling cold or warm
- Behavioral problems
- Brittle nails
- Hair thinning or loss
- Learning deficiencies
- Lethargy or low blood pressure
- Sore bones and joints
- Watery or swelling eyes
When there is a pretty good possibility that something is harmful, as is the case with soy, common sense dictates that it's better to avoid it!
The corporations who make billions from selling soy would like us to believe that until the dangers of soy are proven beyond a shadow of a doubt, we shouldn't worry about them. This reminds me of Russian roulette: if a gun had a hundred chambers, and only one was loaded, I wouldn't risk putting it to my head and pulling the trigger. Would you?
Or, as Roger Eichman, DDS, succinctly summed up the precautionary principle:
"The precautionary principle requires action once the possibility of harm exists. It does not require proof beyond a shadow of a doubt."There's more than enough sound scientific evidence to convince me. I used to think soy was a good dietary choice, but not anymore. I quit eating it a long time ago.
For more information about the dangers of soy, go to the Weston Price Foundation.