The Truth About Soy

Soy is a controversial subject in many circles. It is claimed to be a health food, but the reality of the matter is that the type of soy we are consuming these days is very different from the traditional fermented soy. I used to drink soy milk and eat protein bars loaded with soy back in the day before I ever learned about its real dangers. Today we want to clear up some of the confusion with this topic by turning to the research.

What We Have Been Told About Soy

  • Soy foods provide complete protein.
  • Soy formula is safe for infants.
  • Soy foods can prevent osteoporosis.
  • Soy foods protect against many types of cancer and heart disease.
  • Soy estrogens (isoflavones) are good for you.
  • Soy foods are good for postmenopausal women.

Dangers found in Soy

The consumption of soy as food dates back to the Chou Dynasty, where it was fermented into foods known as tempeh, miso, natto, and soy sauce. If the soybeans were unfermented they were inedible due to the fact that they contained large amounts of natural toxins or “antinutrients.” Most modern soy foods are not fermented to neutralize these toxins and are processed in ways that increase levels of carcinogens, which are agents directly involved in causing cancer. The Weston A. Price Foundation does an amazing job at summarizing these dangers:

  • High levels of phytic acid in soy reduces assimilation of calcium, magnesium, copper, iron, and zinc. This can only be neutralized by long fermentation as mentioned above. High phytate diets have been known to cause growth problems in children.
  • Trypsin inhibitors in soy interfere with protein digestion, may cause pancreatic disorders, and lead to stunted growth.
  • Soy phytoestrogens disrupt endocrine function and have the potential to cause infertility and promote breast cancer in adult women. These phytoestrogens are potent antithyroid agents that cause hypothyroidism and may cause thyroid cancer. In infants, consumption of soy formula has been linked to autoimmune thyroid disease. (Remember too that, they are also recognized by both the male and female body as a reproductive hormone, as estrogen. They can have different effects on breast, uterine, and prostate tissues).
  • Vitamin B12 in soy is not absorbed and actually increases the body’s requirement for B12. (Most vegetarians consume soy for the Vit B12, but sadly it’s not doing much good).
  • Soy foods increase the body’s requirement for Vitamin D, and toxic synthetic vitamin D2 is added to soy milk. (We have already discussed how important Vitamin D is for our bodies).
  • Processing of soy protein results in the formation of toxic lysinoalanine and highly carcinogenic nitrosamines.
  • MSG, a potent neurotoxin, is formed during soy food processing and additional amounts are added to many soy foods to mask soy’s unpleasant taste.
  • Soy foods contain high levels of aluminum, which is toxic to the nervous system and the kidneys.

Soy and Estrogen

I want to expand a little more on this subject as mentioned above and for good reason… soy really can screw up our hormones.

  1. Soy and Men- if there is an imbalance of testosterone to estrogen in men this can lead to decreased sex drive, loss of energy, fat accumulation, and gynecomastia, which is the enlargement of breast tissue in males. 
  2. Soy and Women-high levels of estrogen in women can disrupt periods, fertility, and increase breast cancer risk.
  3. Soy and Infants- According to The Weston A. Price Foundation, babies fed soy-based formula have 13,000-22,000 times more estrogen compounds in their blood than babies fed milk-based formula. Infants exclusively fed soy formula receive the estrogenic equivalent of at least four birth control pills per day. Soy infant feeding- which flood the bloodstream with female hormones that inhibit testosterone cannot be ignored as a possible cause of disrupted development patterns in boys, including learning disabilities and ADD. Some girls are showing sexual development before the age of three. Intake of phytoestrogens even at moderate levels during pregnancy can have adverse affects on the developing fetus and the timing of puberty later in life.

Soy- Based American Diet

You may be thinking that you are ok because you do not eat soy products. Well, the average American probably does not realize just how much soy there truly is in his or her diet. According to the article Soy and Seizures by Kaayla T. Daniel, PhD, soy ingredients are found in more than 60 percent of packaged and processed foods (foods such as canned tuna, cereals, margarine, infant formulas, even cosmetics, vitamins, and prescription drugs) and nearly 100 percent of fast foods. Another interesting fact is that most animal products (commercial eggs, milk, and meats) contain residual isoflavones from soy-based feeds. Needless to say we have all eaten soy whether we wanted to or not. Do not be fooled into believing that Asians are eating lots of soy foods either. In reality Asians eat very little soy and the soy that they do eat is fermented.

Where Does This Leave Us?

In general, if soy is not fermented, stay away from it. If you do choose to eat fermented soy do so in small amounts. Here are some of the soy “foods” you want to avoid:

  • soymilk
  • soybean oil
  • soy protein
  • edamame
  • soy cheese, ice cream, or yogurt
  • tofu
  • soy protein powders
  • soy infant formula

The absolute best way to avoid soy foods is to eat real whole food. Avoid processed foods and you are well on your way!

Additional Research:
  1. The Dangers of Soy
  2. The Soy Ploy
  3. Soy can Damage Your Health
  4. Myths and Truths About Soy
  5. The Truth About Unfermented Soy and its Harmful Effects
  6. Avoid Soy
  7. Soy and the Brain
  8. Soy Formula Birth Control Pills for Babies
  9. The Tragedy of Soy Infant Formula
  10. The Whole Soy Story

15 thoughts on “The Truth About Soy

  1. AdamLehman says:

    When I talk about this to people, they look at me like I’m nuts. Soy is so much thought to be a health food. Great post here Mary!

  2. Natalie @ NS Pottery says:

    Love that top photo- “No Joy in Soy” :) I, too, used to eat soy years ago when I was first wanting to eat healthier. Thank goodness it didn’t take long for me to learn that it really isn’t good for us because after that tofu cake for my 15th birthday… :P

  3. Anna Pedersen says:

    Hi Mary, Interesting article! Why is edamame (something I consider a “real whole food”) on the avoid list?

    1. Considering You says:

      Anna, I chose to list it there because it is not fermented. It’s a personal choice if you want to eat it, but I recommend moderation because it is still goitrogenic (thyroid suppressing). Hope that helps!

  4. Spark Your Self says:

    Yes! I couldn’t agree with this more – I was drinking soy for about 10 years thinking I was making the ‘healthy’ choice, but stopped drinking it about a year ago and feel so much better for it. I had adult acne for so many years which disappeared as soon as I stopped drinking soy, and my skin flares up every time I drink soy. Thanks for posting!

  5. Laura Armstrong says:

    This is great to think about. What are your recommendations for someone like me who chooses soymilk in my lattes over regular milk because of a lactose intolerance? Should I switch over to almond or rice milk? It just seems harder to come by in coffee shops!

    1. Considering You says:

      I would switch over to full fat coconut milk or try almond milk instead. There really is no alternative in a coffee shop unless you learn to love black coffee. Not sure if that helps but at least switch over at home for sure!!

  6. Katie Gunser says:

    What kind of protein power can I use then in my smoothies? It seems like soy is in EVERYTHING! ugh!


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