Part 1 is HERE

Below outlines how different foods, vitamins, minerals and toxins effect Thyroid function. Abnormalities determined by lab tests can be normalized by incorporating and/or eliminating certain foods and supplements.

DIETARY GOITROGENS – Interfere with Iodine Uptake and impair the synthesis of Thyroid Hormone

Cassava, lima beans, linseed, sorghum, sweet potato, maize, millet - Contain cyanogenic glucosides, when metabolized release free cyanide and thiocyanates which impair iodine uptake.

Cruciferous vegetables: cabbage, kale, cauliflower, broccoli, brussel sprouts, turnips, rapeseed, kohlrabi, rutabaga, mustard, and horseradish – Metabolized to goitrin or thiocyanates and isothiocyanates, causing inhibition of iodide trapping and thyroid peroxidase activity.

Rosaceae Fruits - Includes almonds, apricots, cherries, peaches, pears, plums, raspberries, and strawberries. All are goitrogenic.

Dairy - Cattle can ingest goitrogens and then pass them to humans through milk. [1][2]

Soy - Flavonoids impair thyroid peroxidase activity, can also interfere with the absorption of synthetic thyroid hormone. [3]

NOTE: Boiling and Pressure Cooking can reduce the goitrogenic content of foods, fermenting will increase it.

THYROID DISRUPTORS – Most important for those who test positive for TPO or Tg antibodies, even if you are within range. Positive test results correlate with sensitivities and allergies to the protein Gliadin. Depending on the individual, these antibody triggers can either decrease or increase T4/T3 levels. [4]

Gluten – Gliadin is a protein found in gluten which has a molecular structure similar to the thyroid gland. Sensitivities to this protein lead to an antibody attack. 35% of the population is sensitive to gluten. [5]

Casein - 50% of people with gluten sensitivity experience molecular mimicry with casein protein. This is known as cross-reactivity, where you react not only to your original trigger, but also to another trigger that resembles the first one. [6][7]

Lectins – Natural plant insecticides most abundant in Legumes and Nightshade vegetables, also found in wheat. Lectins contain a gluten-like protein known to cause inflammation in those with RA. Can damage the intestinal lining, leak through the gut wall and deposit themselves in distant organs and glands. The plant lectin, wheat germ agglutinin, can also cause insulin resistance. [8][9][10]

NOTE: Pressure cooking can reduce the amount of lectins in food, slow cooking can potentiate it.

VITAMINS & MINERALS

Selenium - Deficiency impairs thyroid hormone synthesis, inhibiting the conversion of T4 to T3. Low doses of Selenium (200 mg/day) can lower TPO-Ab.

Iron – Plays an important role in thyroid metabolism. Deficiency reduces thyroperoxidase activity and may inhibit iodine prophylaxis leading to thyroid disorders.

Vitamin A - Serum thyroxine and thyroid function is affected by the serum level of vitamin A. Deficiency causes suppression of the pituitary TSHβ gene.

Iodine – A double edged sword, iodine deficiency and excess are associated with an increased risk of thyroid disorders.

Calcium - Goitrogenic in excess of 2 g per day. Decreases iodide clearance by the thyroid causing iodine deficiency. Calcium also reduces the absorption of thyroxine. [11]

NOTE: Liver, kidney, grass fed meat and pastured eggs are good sources of Selenium, Iron, Vitamin A and Iodine.

THYROID STIMULATORS

Tyrosine – Amino Acid used by the Thyroid Gland in conjunction with iodine to make thyroid hormone.

Ginger – Subacute thyroiditis can be induced by ginger through an autoimmune process that changes antigenic properties of thyroid follicular cells. [12]

Pineapple – Can elevate serum T3 and T4 levels in subjects who are euthyroid. [13]

Desiccated thyroid (PMG, Glandular) - Contains biologically active thyroid hormone which can induce hyperthyroidism. Can also act as a dummy target organ for Thyroid antibodies to attack.

Ephedrine - Can raise both Free T4/T3 by 8% - 12%

THYROID TOXINS

Halogens - Bromine, Chlorine, and Fluorine are iodine look-alikes. These chemicals can be found in our water, food, and household products and look similar enough to iodine that your thyroid can absorb them in place of iodine, effectively displacing iodine and reducing its ability to produce thyroid hormone.

Quercetin - Flavanoid found in many plants and foods, such as red wine, onions, green tea, apples, berries, Ginkgo biloba, St. John's wort, American elder, and Buckwheat. Quercetin possesses anti-thyroid and goitrogenic effects when in excess and can cause permanent destruction of the thyroid. [14]

Heavy metals - Mercury, Cadmium, Aluminum and Lead are known to affect thyroid function. Can be detoxed using various forms of Magnesium (malate, glycinate), Zinc, Vitamin C and MSM (Methylsulfonylmethane). [15]

Glycophosphate – Roundup Weed Killer, found in GMO and Non-Organic foods such as wheat, barley, buckwheat, millet, rice, oats, wild rice, popcorn, sorghum, corn, and canola. Said to be the cause of undiagnosed (silent) celiac disease and is associated with a 4-fold increased risk of death. Can disrupt the digestive process by inhibiting enzymes protease, lipase, and amylase. [16]

SOURCES:
1. https://www.ncbi.nlm.nih.gov/books/NBK285556/table/tyd-iodine-deficienc....
2. https://www.jacionline.org/article/S0091-6749(00)15898-1/pdf
3. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4740614/
4. https://www.ncbi.nlm.nih.gov/pubmed/15244201
5. https://www.enterolab.com/StaticPages/EarlyDiagnosis.aspx
6. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5435852/
7. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5574310/
8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1115436/
9. https://www.ncbi.nlm.nih.gov/pubmed/25633332
10. https://www.ncbi.nlm.nih.gov/pubmed/6989266
11. https://www.ncbi.nlm.nih.gov/books/NBK285560/
12. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2876930/
13. http://www.innspub.net/wp-content/uploads/2017/03/IJB-V10No3-p173-184.pdf
14. https://www.ncbi.nlm.nih.gov/pubmed/24447974
15. https://www.ncbi.nlm.nih.gov/pubmed/30989610
16. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3945755/