Avoid Soy for Thyroid Health

. 4 min read

Everybody’s eating soy these days. Soy is a not good for you for many reasons. One of the biggest reasons is that soy depresses thyroid function.

Soy products increase the risk of thyroid disease. Source
For adults, just 30 mg of soy isoflavones per day is the amount found to have a negative impact on thyroid function. This amount of soy isoflavones is found in just 5-8 ounces of soy milk, or 1.5 ounces of miso. Source

30 mg of isoflavones daily will depress thyroid function in an adult. What about a child? If I had to guess, I’d say half that amount — 15 mg of isoflavones per day. According to the Soy Online Service, for infants, any soy is too much.

I worry about vegans the most, because they eat copious amounts of soy. Just look at this list of 101 vegan meals — over half of them are made with soy.

Read more about the dangers of soy on the Soundness of Body & Mind blog.

Bread with added soy flour, 2 slices 4 mg
Meatless chicken nuggets, 1/2 cup 15 mg
Soy hot dog 15 mg
Soymilk, 8-ounce glass 20 mg
Green soybeans, raw, 1/2 cup 20 mg
Miso, 1/4 cup 21 mg
Tofu, 1/2 cup 28 mg
Soy cheese, 1/2 cup 31 mg
Tempeh, cooked, 1/2 cup 53 mg
Soybean chips , 1/2 cup 54 mg
Mature soybeans, cooked, 1/2 cup 55 mg
Dry roasted soybeans , 1/2 cup 128 mg
Revival soy-based meal replacement, 1 serving 160 mg Source

OK, you say, I’m not a vegetarian and I don’t drink soy milk, nor do I feed it to my kids. So I’m probably OK, right?


What’s scary about this is how ubiquitous soy is. It’s really hard to avoid it since it’s in almost everything. No wonder Americans are getting so fat. It’s the thyroid that controls our metabolism.

Many restaurant foods contain soy. Almost all restaurants fry their foods in soybean oil. Mayonnaise, salad dressings, and anything fried — including French fries — are the worst.

And almost all packaged foods contain soy. Take a look at some of the following popular packaged foods. Every single one of them contains soy.

Wheat Thins Ingredients: Enriched flour (wheat flour, niacin, reduced iron, thiamine mononitrate (vitamin B1), riboflavin (vitamin B2), folic acid), soybean oil, whole grain wheat four, sugar, defatted wheat germ, cornstarch, malt syrup (from barley and corn), high fructose corn syrup, monoglycerides, salt, vegetable color (annatto extract, turmeric oleoresin), soy lecithin.

Campbell’s Tomato Soup Ingredients: Tomato Puree (Water, Tomato Paste), Water, High Fructose Corn Syrup, Wheat Flour, Salt, Vegetable Oil (Corn, Cottonseed, Canola and/or Soybean), Flavoring, Ascorbic Acid, and Citric Acid.

Doritos Nacho Cheesier Tortilla Chips Ingredients: Whole Corn, Vegetable Oil (Contains One or More of the Following: Corn, Soybean and/or Sunflower Oil), Salt, Cheddar Cheese (Cultured Milk, Salt, Enzymes), Maltodextrin, Wheat Flour, Whey, Monosodium Glutamate, Buttermilk Solids, Romano Cheese from Cow’s Milk (Part-Skim Milk, Cheese Cultures, Salt, Enzymes), Whey Protein Concentrate, Onion Powder, Partially Hydrogenated Soybean and Cottonseed Oil, Corn Flour, Disodium Phosphate, Lactose, Natural and Artificial Flavor, Dextrose, Tomato Powder, Spices, Lactic Acid, Artificial Color (Including Yellow 6, Yellow 5, Red 40), Citric Acid, Sugar, Garlic Powder, Red and Green Bell Pepper Powder, Sodium Caseinate, Disodium Inosinate, Disodium Guanylate, Nonfat Milk Solids, Whey Protein Isolate, and Corn Syrup Solids.

Similac Infant Formula Ingredients: Nonfat Milk, Lactose, High Oleic Safflower Oil, Soy Oil, Coconut Oil, Galacto-Oligosaccharides – GOS – Sourced from Milk, Whey Protein Concentrate, C. Cohnii Oil – DHA – Source of Docosahexaenoic Acid, M. Alpina Oil – ARA – Source of Arachidonic Acid, Beta-Carotene, Lutein, Lycopene, Potassium Citrate, Calcium Carbonate, Ascorbic Acid, Soy Lecithin, Potassium Chloride, Magnesium Chloride, Ferrous Sulfate, Choline Bitartrate, Choline Chloride, Ascorbyl Palmitate, Sodium Chloride, M-Inositol, Zinc Sulfate, Mixed Tocopherols, D-Alpha-Tocopheryl Acetate, Niacinamide, Calcium Pantothenate, L-Carnitine, Vitamin A Palmitate, Cupric Sulfate, Thiamine Chloride Hydrochloride, Riboflavin, Pyridoxine Hydrochloride, Folic Acid, Manganese Sulfate, Phylloquinone, Biotin, Sodium Selenate, Vitamin D3, Cyanocobalamin, Calcium Phosphate, Potassium Phosphate, Potassium Hydroxide, Nucleotides, Adenosine 5′-Monophosphate, Cytidine 5′-Monophosphate, Disodium Guanosine 5′-Monophosphate, Disodium Uridine 5′-Monophosphate.

Kirkwood Chicken Nuggets Ingredients: Chicken Breast with Rib Meat, Water, Bleached Wheat Flour, Enriched Bleached and Unbleached Wheat Flour (Enriched with Niacin, Reduced Iron, Thiamine Mononitrate, Riboflavin, Folic Acid), Textured Soy Protein Concentrate, Contains 2% or Less of Salt, Modified Food Starch, Dextrose, Spice, Wheat Flour, Sodium Phosphates, Yellow Corn Flour, Soybean Oil, Wheat Gluten, Yeast, Extractives of Paprika, Dried Egg Whites, Leavening (Sodium Acid Pyrophosphate, Sodium Bicarbonate), Dried Whey, Hydrolyzed Soy Protein.

Hellman’s Real Mayonnaise Ingredients: Soybean Oil, Water, Whole Eggs and Egg Yolks, Vinegar, Salt, Sugar, Lemon Juice, Natural Flavors, Calcium Disodium EDTA (Used to Protect Quality).

Newman’s Own Olive Oil and Vinegar Salad Dressing Ingredients: Olive Oil, Vegetable Oil, Soybean Oil and/or Canola Oil, Water, Red Wine, Vinegar, Onion, Spices, Salt, Garlic, Lemon Juice, and Distilled Vinegar.

Photo credit: Morgan Tepsic