Girl Planting seeds

Oh, how I gloated over the fact that I gave my kids so much soy when they were growing up.  We were vegetarians then, and I felt so proud serving them soy sausages, soy hot dogs, soy smoothies, soy milk, soy ice cream. I thought I was the best mom on the block…that is until I found out the full soy story.   See, there is a dark side to soy and since making that discovery, I must say I feel a little guilty about all that soy I placed on their plates.  Now older and with a little more humility, I council others to move away from soy unless it is fermented (tempeh, miso, etc.).  Here are a few of the reasons why when asked today if I want some soy, this corny girl from Jersey responds, “soy tinly not!”


A Few Reasons to Stir Clear of Soy:


1.    GMO:  Approximately 93% of U.S. soy crop planted in the U.S. is genetically modified.


2.    Allergies: Soy is one of the main allergens identified via 1. IgE blood testing (which identifies immediate reactions such as hives) 2. IgG blood testing (can help identify allergens that cause delayed reactions such as headaches or fatigue which present a day or two after consuming a food) and 3. An elimination diet. In addition, allergic symptoms often associated with soy are bedwetting in children, joint pain in adults and GI disturbances such as gas and bloating.


3.    Most Soy is Non-Fermented:  Most soy products (soy protein powder, soy milk, soy hot dogs or patties) are not fermented, meaning they contain “phytates” which block the absorption of certain minerals (calcium, magnesium, zinc, copper and iron).  Additionally, unfermented soy contains enzyme inhibitors which limit the body’s ability to digest and absorb the protein contained in soy.  Nature put phytates there for good reason, as these toxic substances make the plant unappetizing to foraging animals, therefore protecting it so it can live longer and reproduce.  However, if you don’t soak or ferment foods that contain these anti-nutrient and enzyme inhibitors, the food will have toxic effects on the body. Many plants have these anti-nutrients but soy is especially high in these chemicals. If soy foods are not property prepared (soaking or fermenting), then according to health author Natasha Longo,”soy is one of the worst foods a person can eat”. 


Since unfermented soy has been linked to GI disturbances, weakened immunity, reproductive problems, allergies, PMS, ADHD etc., the only sources of soy that should be consumed are the fermented ones: miso, tempeh, natto and fermented tofu.


4.    Soy Can Lead to Hormonal Imbalances: Contrary to what we once thought, soy most likely does not protect women against breast cancer:   One study done in the late 90’s showed that dietary sources of estrogens (phytoestrogens in soy) at low concentrations do not act as anti-estrogens but rather they act more like DDT and estradiol (harmful form of estrogen) and stimulate human breast cancer cells to enter the cell cycle (1).   Due to its endocrine disrupting potential, soy has also been linked to infertility, and toxicologists are now estimating that an infant exclusively fed soy formula receives the estrogenic equivalent of at least five birth control pills per day.   (4)


5.    Thyroid Problems:   Several studies have shown an association between excessive soy consumption and thyroid problems such as hypothyroidism, goiter, autoimmune thyroid disease (2) and an increased requirement for iodine (3).  In infant’s consumption of soy formula has been linked to autoimmune thyroid disease.


6.    A link to cancer: processing of soy can cause the formation of toxic lysine-alanine, a highly carcinogenic nitrosamine. 


7.    Soy Contains: free glutamic acid or MSG, a known neurotoxin formed during the processing of soy food. Additional amounts of MSG are frequently added to many soy foods.


8.    Heavy Metals: Soy foods can also contain high levels of the heavy metal aluminum which is a known nervous system toxin.


I’ll be the first to admit that in my quest to give myself and my family the most nutritious diet, I fell prey to the marketing strategies and advertising campaigns designed to convince us all that soy had incredible health benefits.   And maybe certain soy foods still do such as the fermented Miso and tempeh.   But in general, when new findings such as those I’ve listed above, as well as the one I’m about to share reveal a darker side to the soy story,  it makes me think twice about consuming my old standby.  

There haven’t been many additional studies to substantiate the findings of this one, but it’s conclusion certainly leaves those of us interested in health and longevity with food for thought: “A study of Japanese American living in Hawaii showed a significant statistical relationship between two or more servings of tofu a 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 disease and dementia and what’s more stated Dr. White (the lead researcher) “those who ate a lot of tofu, by the time they were 75 or 80 looked five years older (5).

I know how frustrating this information can be. Soy, the very food I once considered “sacred” is being shaken off its pedestal. This information can be quite humbling and makes me want to continue to grow, learn, and above all, keep an open mind as new information informs the food choices we make.



1.       Dees, C et. Al:  Environ Health Perspect. 1997 Apr;105 Suppl 3:633-6. Dietary estrogens stimulate human breast cells to enter the cell cycle.  

2.       Nihon, N et al, The Effects on the Thyroid gland of soybeans administered experimentally in healthy subjects, 1991 May 20;67(5):622-9.


3.       Tran, L, et al,  Soy Extracts suppressed iodine uptake and stimulated the production of autoimmunogen in rat thyrocytes, Exp Biol Med Maywood 2013 June;238(6) 623-30  


4.       Setchell, K.D. et al., "Isoflavone content of infant formulas and the metabolic fate of these early phytoestrogens in early life", American Journal of Clinical Nutrition, December 1998 Supplement, 1453S-1461S.


5.       White, LR, et al, Brain aging and midlife tofu consumption, J Am Coll Nutr 2000 April:19(2) 242-55


6.       General reference:

Maureen “Mo” McDonnell, RN Maureen is the Medical Coordinator of the Imus Ranch for Kids with Cancer in New Mexico, the co-founder of Saving Our Kids, Healing Our Planet (, and owner of Nutritionist’s Choice vitamins. She and her husband have seven grandkids and feel blessed to be living in the beautiful mountains of North Carolina.

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