There has been a growing interest in dietary supplements for supporting thyroid dysfunction. Many patients with thyroid dysfunction often have underlying autoimmunity or are currently taking medication. Although these individuals may have normal lab values, they are often still symptomatic and are looking for additional support. Iodine is most recognized as the major supportive nutrient of the thyroid; however, several other nutrients play an essential role as well.

According to a review published last month in Nutrients, researchers investigated various nutrients that play important roles in thyroid function and immunity, including selenium, l-carnitine, myo-inositol, melatonin, and resveratrol.

Their Findings:

Carnitine
The amino acid derivative carnitine has been used in patients with hyperthyroidism.  It was found that dosing at 2 grams per day has been shown to control hyperthyroid symptoms by acting as a peripheral antagonist of thyroid hormone.

Inositol
Inositol is commonly used to support sleep and female hormone health, as well as to help support healthy mood and relaxation. Inositol is also a second messenger regulating several hormones such as insulin and TSH. One study showed myo-inositol alone caused almost a 3.5% increase in free T4 and a 10% decrease in TSH levels. Another study showed a significant reduction in TSH levels in Hashimoto’s patients with subclinical hypothyroidism and increases in thyroid hormone concentrations with myo-inositol combined with selenium. In addition, there was a lower TPO (thyroid peroxidase) antibody concentration in both groups but only a reduction in thyroglobulin antibodies in the myo-inositol with selenium group. Dosing ranged from 600 mg up to 4 grams per day.

Selenium
Selenium has also shown to be beneficial for thyroid dysfunction. When comparing all tissues in the body, the thyroid gland has the highest concentrations of selenium. It is required for normal thyroid function as well as thyroid hormone synthesis. Studies have demonstrated benefits in Graves’ ophthalmopathy. In addition, a benefit has been seen in Hashimoto’s thyroiditis on serum thyroid autoantibodies. Selenium status has an effect on immune function and newly diagnosed autoimmune thyroid patients tend to have low selenium concentrations.

Based on this literature review, there is evidence to support the use of carnitine, inositol, and selenium in thyroid conditions. There may also be possible benefits from melatonin and resveratrol; however, there is a lack of studies to draw a definitive conclusion at this time.

By Michael Jurgelewicz, DC, DACBN, DCBCN, CNS

Source: Benvenga S, Feldt-Rasmussen U, et al. Nutraceutical Supplements in the Thyroid Setting: Health Benefits beyond Basic Nutrition. Nutrients. 2019 September 13;11(9).