170 Evidence-Based Reasons Why Soy is Damaging to Your Health

Soy beans toxic damaging

With a mountain scientific data available showing that soy is a highly toxic, estrogenic and goitrogenic bean, it shocks me how many folks are still on the “soy is good for you” bandwagon – even people who should know better like your doctor!

I just got an email from a reader the other day who had been to multiple doctors, both holistic and conventional, and all but one of them were telling her that plenty of soy in her diet would help her menopause symptoms.

Medical doctors are expert drug dealers who know literally almost nothing about nutrition.  The reality is the recommendation to eat more soy can result in any number of health problems and diseases.

Fermented soy in small, condimental amounts as practiced in traditional Asian cultures is fine for those who have healthy thyroid function.   Only miso, tempeh, natto and soy sauce (IF traditionally brewed) fall under this category.

Eat any form of soy aside from these regularly and you’re headed for a world of hurt.  The hypothyroidism that soy’s powerful goitrogenic chemicals cause can lead to virtually all symptoms and disease pathologies that exist.

For those of you surprised by the notion that soy is not actually the health food you’ve been told it is, here are 170 scientific reasons that will show you exactly why it is so.

1) Soy is Goitrogenic

A 1991 study found that eating only 2 TBL/day of roasted and pickled soybeans for 3 months to healthy adults who were receiving adequate iodine in their diet caused thyroid suppression with symptoms of malaise, constipation, sleepiness, and goiters (Nippon Naibunpi Gakkai Zasshi 1991, 767: 622-629)!

2) Soy Causes Delayed Menstruation

Six premenopausal women with normal menstrual cycles were given 45 mg of soy isoflavones per day.  This is equivalent to only 1-2 cups of soy milk or 1/2 cup of soy flour!   

After only one month, all of the women experienced delayed
menstruation with the effects similar to tamoxifen, the anti-estrogen drug given to women with breast cancer (American Journal of Clinical Nutrition 1994 Sep;60(3):333-340).

3) Soy is Estrogenic

Dietary estrogens in the form of soy foods were found to have the potential to disrupt the endocrine system with the effects in women similar to taking the breast cancer drug tamoxifen (Proceedings of the Society for Experimental Biology and Medicine 1995 Jan;208(1):51-9).

4) Soy Can Cause Cancer

Estrogens consumed in the diet at low concentrations were found to stimulate breast cells much like DDT to increase enzymatic activity which leads to breast cancer (Environmental Health Perspectives 1997 Apr;105 (Suppl 3):633-636).

5) Soy Contains Estrogenic Isoflavones

The soy isoflavones genistein and daidzein appear to stimulate existing breast cancer growth indicating risk in consuming soy products if a woman has breast cancer. (Annals of Pharmacotherapy 2001 Sep;35(9):118-21).

6) Soy is Anti-Thyroid

Direct evidence that soy isoflavones genistein and daidzein suppress the pituitary-thyroid axis in middle-aged rats fed 10 mg soy isoflavones per kilo after only 3 weeks as compared with rats eating regular rat chow (Experimental Biology and Medicine 2010 May;235(5):590-8).

7) Soy Detrimental to developing Fetus

Scientific research has shown that the developing male fetus which is exposed to soy phytoestrogens may suffer from higher susceptibility to prostate cancer later in life (Prostate 1994;24(2):67-78).

8) Soy Causes Early Puberty

Dietary genistein (soy phytoestrogen) in developing female rats had the effect of significantly accelerated puberty (Toxicol Sci 1999 Oct;51(2):236-44).

9) Soy Reduces Testosterone

A study of 12 men aged 18 years and older experienced a 19% drop in serum testosterone in only 28 days when supplemented with 56 grams of soy protein powder over that same time period (Prev 2007;16:829–33).

10) Soy Formula Damages Reproduction

Female newborns who are orally exposed to genisin, the glycosylated form of genistein (soy phytoestrogen) experienced harm to the reproductive system in the form of “delayed vaginal opening… abnormal estrous cycles, decreased fertility, and delayed parturition.” (Environmental Health Perspective 2009 Dec;117(12):1883-9).

160 More Reasons Soy is Toxic

Still interested to see the remaining 160 reasons?  My friend Dr. Kaayla Daniel, author of the must read The Whole Soy Story, has compiled the rest of the list for you if you click here.


Still think soy is a health food?  If you’re wondering why you’ve been taught to think it is, just follow the money.  The industry selling soy products and marketing them as health foods is the reason why.

People need to understand that corporations will not hesitate to lie to you if it means profit for them.  If you value your health, avoid soy like the plague.