Diet and Thyroid Health
- Optimal thyroid functioning is a factor of many variables that also include proper dieting. Some diets are known to improve thyroid health by improving thyroid hormone synthesis and metabolism.
- Iodine supplementation has long been proven to offer direct benefits to the thyroid. Selenium, Gluten, Coffee and Cruciferous vegetables all affects thyroid health.
- Deficiency in the right diets needed for normal thyroid function can cause a spectrum of disorders referred to as ‘Iodine Deficiency Disorders’ (IDD).
- Iodine deficiency disorders can degenerate and cause more serious diseases if not properly managed. Therefore it is recommeneded that 12.5mg of Iodine/Iodide per day should be taken.
- The Thyroflex Test is more accurate (about 98%) when compared with Thyroid Blood Test. When combined with 12.5mg of Iodine/Iodide per day
Cellular regeneration, normal metabolism, and biochemical synthesis of enzymes and body hormones are all partially depended on a diet plan that supplies the essential and traces nutrients in the right absorbable quantity. Depending on an individual’s health index –immunity status and presence of underlying diseases, the number of nutrients needed might differ significantly in a population.
Iodine has long been confirmed by different health researches to have a profound influence on the status of thyroid health in humans. Severe deficiency in this nutrients is linked with impaired synthesis of thyroid hormones and a resultant under-functioning of the thyroid. Beyond thyroid health, severe iodine deficiency has also been linked to endemic mental retardation, infertility, and cretinism. Currently, the normal recommended intake of Iodine is pegged at a range of 100-150mcg/day. Pregnant women are advised to adopt a diet that supplies about 220mcg of Iodine daily, to reduce the risk of thyroid disease associated with pregnancy, especially transient bouts of postpartum thyroiditis. The US Institute of Medicine advised a recommended dietary allowance of 290mcg/day in lactating women. However according to the research carried out by Abraham, Flechas et.al. the recommernded dose is 12.5 mg of Iodine/Iodide with 5 mg iodine and 7.5 mg of iodide in the proportions established by Lugol, per day. this was put ito practice by Browstein with outstanding results.
The body converts dietary Iodine to Iodide –a form readily absorbed from the gut. Iodine is transported in this form to the follicle cells of the thyroid where it is concentrated and stored. The deposit of Iodide in these cells are needed for the synthesis of thyroxine (T4) and triiodothyronine (T3). Individuals with an inadequate intake of Iodine are at great risk of decrease serum level of thyroxine and triiodothyronine. By a cascade of feedback mechanism, the Pituitary gland senses the depletion and release more thyroid-stimulating hormone. This hormone, in turn, increases iodine uptake, leading to the growth of the thyroid follicular cells and increased synthesis of the thyroid hormones.
The thyroid hormones ensure normal neuronal development and regulate the overall metabolic rate of the body systems. Impaired functioning of the thyroid hormones causes a spectrum of disorders collectively referred to as ‘Iodine Deficiency Disorders’ (IDD). Iodine supplementation by dieting plans has been recommended as an effective preventive measure in preventing these diseases. Dietary sources of Iodine common in the population include seafood, pieces of bread and grains. These iodine sources and selenium are micronutrients that can modify the levels of thyroid antibody titers.
A customized diet plan with food products that can influence thyroid health is sometimes beneficial as they improve the prognosis of thyroid diseases. Expert advice is, however, needed to create such plans including dietary supplementation of iodine/iodide as the disease risk and severity must be assessed.
In addition to iodine-containing diets, we have provided an outline of the different types of food products with science-based evidence of their influence on Thyroid health.
Soy and soy-derived food products are stapled constituents of common diets in the East and South Asian Countries. Soy has long been rumoured by natural product experts to offer beneficial effects in the management of breast cancer, prostate cancer and osteoporosis. In its different presentations, this product contains two main classes of bioactive components –Soy isoflavones and soy proteins. Isoflavones, as a major class of plant flavonoids, exists in food products as genistin and diazin. Specifically, in soy, isoflavones present as b-D-glycosides. Medical interests in soy products spiked when a review published by the New England Journal of Medicine reported the occurrence of goitre in infants nourished with soy-containing infant formula.
This report lends credence to the speculation within the medical community on the ability of soy to reduce the rate of absorption of synthetic thyroid hormones. In 2000, the Journal of Toxicology and Applied Pharmacology published a report that demonstrated the inhibitory effect of soy on the activity of thyroid peroxidase in rats. The experimental rats expressed thyroid impairments with typical symptoms that suggest decreases synthesis of thyroxine and triiodothyronine.
Cruciferous vegetables are common components of diets across the world. They include broccoli, cauliflower and cabbage. These vegetables contain high concentrates of glucosinolates –Sulphur-containing products which hydrolyze mostly to isothiocyanates and indole-3-carbinol. The link between cruciferous vegetables and thyroid health is established in the presence of another compound –progoitrin. The hydrolysis of this compound produces goitrin, a compound which has been proved to interfere significantly with thyroid hormone synthesis. In iodine-deficient individuals, high consumption of cruciferous vegetables increases the risk of nodular thyroid cancer as the levels of circulating goitrin increases significantly.
Upon hydrolysis, the indole glucosinolate deposits in cruciferous vegetable releases thiocyanate (TCN) ions into the body system. These ions are transported to the thyroid where they inhibit iodide transport and effect a competitive displacement of iodide ions. An overload of thiocyanate ions (detected by measuring TCN levels in the body fluids) initiates a graded anti-thyroid property in euthyroid individuals, prominently causing goitre and different ranges of thyroid impairment.
Selenium-containing Food Products
Rich dietary sources of selenium include pieces of bread, eggs, fish and meat. Brazil nuts are known to supply about 90mcg of selenium in a single nut. This micronutrient is essential in optimal metabolism of the thyroid hormones. Selenium supplementation is recommended in the adjunctive management of thyroid eye disease. Different medical enquiries have published results supporting the use of selenium in the reduction of serum thyroid antibody titers. This effects maintain normal thyroid function and also improve the prognosis of thyroid dysfunctions –especially in Thyroid Eye Disease. In 2013, Clinical Endocrinology –a journal with a focus on practical clinical endocrinology, published a review detailing the reduction of anti-thyroid antibodies in Hashimoto’s patients placed on selenium supplementation. According to this review, selenium supplementation resolves symptoms of Graves’ disease and improves the ultrasound structure of the thyroid gland. Some thyroid pathology reports have also established a link between low selenium levels and increased risk of thyroid cancer.
There are many speculations about the beneficial effects of a gluten-free diet in the management of autoimmune thyroid disorders accompanied by celiac disease. The protein portion of gluten is made of gliadin –a protein with a close resemblance to the protein component of the thyroid. In celiac disease, the body develops an immune reaction to ingested gluten in the small intestine. On breaching the protective barrier of the gut, gliadin is rapidly destroyed by the immune system, which also produces gliadin antibodies for future invasions. In some cases, these antibodies can, in turn, attack the protein component of the thyroid and lead to an onset of Hashimoto’s –an autoimmune disease of the thyroid.
Immune response to gliadin can last for about six months in some individuals. In 2019, the Journal of Experimental and Clinical Endocrinology and Diabetes published the results of a study that investigated the effects of a gluten-free diet on thyroid autoimmunity and the activity of the hypothalamic-pituitary-thyroid axis. The results obtained suggested that a gluten-free diet offers clinical benefits to women with autoimmune thyroid disease as the gluten-free diet reduced thyroid antibody titers and also increases levels of 25-hydroxyvitamin D in subject individuals.
Coffee is, no doubt a widely consumed beverage across different regions. It contains numerous bioactive compounds including polyphenols, diterpenes, melanoidins and caffeine. Currently, the results of medical reports detailing the effects of coffee on thyroid health are inconsistent. However, a report published by Thyroid confirmed that coffee significantly reduces the abdominal absorption of levothyroxine in thyroid replacement of therapy. There are also published reports suggesting that coffee also lowers serum TSH levels. These combined effects suggest that the uncontrolled intake of coffee can alter thyroid functioning and worsen thyroid disease in different patients.
It is important to note that the effects of diets of thyroid health are not definite across a population. An accurate thyroid function test is needed to determine the effects of diet on the thyroid. Thyroid Blood Tests are considered inefficient in evaluating thyroid health as it only measures the level of thyroid hormone present in the blood. According to the submissions of Dr Richard Bayliss, only a meagre percentage (about 18%) of these hormones are present in the blood with the greater percentage found in the skin, muscle and brain.
The Thyroflex Test gives an accurate picture of thyroid functioning. This test evaluates thyroid health by measuring the rate of reflex conduction through the muscles. This measurement is combined with the Resting Metabolic Rate and the range of symptom presentation to assess thyroid health.
- David Brownstein, MD., Iodine. Why You Need It Why You Can’t Live Without It. 2nd Ed. 2006
- Brownstein, D., Clinical experience with inorganic, non-radioactive iodine/iodide. The Original Internist, 12(3):105-108, 2005