By Neil Levin, CCN, DANLA. Posted August 12, 2011.
People typically seek thyroid support nutrients as a way to enhance their energy levels, enable proper control of their body temperature, and support a strong metabolic rate. We take these nutrients, both individually and in formulas, in order to assure adequate levels to support optimal thyroid function, since a deficiency or insufficiency of key nutrients could reduce the operational efficiency of the thyroid gland. Proper thyroid function supports a lean body composition and helps prevent fatigue. Under the control of complex feedback and signals from the hypothalamic-pituitary-thyroid axis, the thyroid gland regulates body temperature and metabolism rates, playing an important role in weight management and energy states. By the same token, if any of the important nutrients are not available to the thyroid in sufficient amounts, metabolic rates and energy levels could suffer. 1
Natural thyroid support supplements work primarily by providing precursors of thyroid hormones, along with various cofactors, in order to encourage proper thyroid function. In some cases, the lack of adequate nutritional resources prevent the thyroid gland from maintaining optimal efficiencies, and if the gland can’t maintain healthy levels of its important hormones, then it can’t adequately support the body’s metabolism. Unlike medical treatments, nutritional approaches focus on providing what the body needs in order to assure that the thyroid has its particular needs met and can function optimally.
The key nutrients for thyroid function are the mineral Iodine and the natural amino acid L-Tyrosine.
Humans require iodine for cellular metabolism and for normal thyroid function; specifically for the production of thyroid hormones. Thyroid hormones regulate many important biochemical reactions, including protein synthesis and enzymatic activity, and are critical determinants of metabolic activity. Iodine is a nutrient that can sometimes be obtained from the soil, but many soils are deficient. Areas that are mountainous, very rainy, or prone to floods/erosion tend to have soils that are low in iodine, increasing the risk that foods grown in those areas will be iodine-deficient. Table salt is commonly iodized, but those using non-iodized salt or on low-sodium diets can’t rely on that source. Multivitamin formulas, thyroid support formulas, kelp and some other seaweeds, and some multimineral formulas provide supplemental iodine. The U.S. Recommended Dietary Allowance (RDA) is 150 mcg (micrograms) daily for adults ages 18 and older, 220 mcg daily for pregnant women, and 290 mcg daily for lactating women. The Tolerable Upper Intake Levels (UL) for adults ages 18 and older is 1,100 micrograms daily. 2-3 ]
The common sources of iodine in dietary supplements include Potassium Iodide, Kelp, and other seaweeds. While kelp and some seaweeds are fine for getting the relatively low RDA level of iodine intake, those seeking much higher levels are usually advised to consider Potassium Iodide. This is because seaweeds typically contain less than 1% iodine, along with a lot of other metals and minerals – including some that we may want to avoid getting too much of – so consuming high doses of seaweeds on a daily basis may not be our safest option. And iodine is a mineral nutrient that needs to be replenished daily.
L-Tyrosine is an amino acid that is important to the structure of most proteins in the body. It is also the precursor of a number of neurotransmitters and hormones, including the major catecholamines dopamine, norepinephrine, and epinephrine (adrenaline), which are stress hormones made by the adrenal glands. In addition to these functions, tyrosine also helps produce melanin (the pigment responsible for hair and skin color) and helps in the function of the adrenal, thyroid, and pituitary glands. Because of these varied responsibilities and the ability of various stresses and dietary deficiencies to reduce tyrosine levels, people sometimes supplement tyrosine (as natural L-Tyrosine) in order to support proper thyroid function. 4-5
How do Iodine and L-Tyrosine affect thyroid function? The thyroid gland’s epithelial cells prepare large quantities of tyrosine into a glycoprotein “scaffold” that is the structural backbone used to form the thyroid hormones thyroxine (T4) and triiodothyronine (T3). The scaffold and iodine are both secreted into the lumen of the thyroid gland, where an enzyme facilitates the hormone synthesis. Other enzymes then separate the hormones from the scaffolding in steps, liberating them into their circulating forms. A few tyrosines are incorporated into these hormones, but most are left in the scaffolding structure’s remains that will be recycled by the body.
Selenium is an essential mineral nutrient that is necessary for normal thyroid hormone metabolism. Selenium-containing enzymes control the synthesis and degradation of the biologically active thyroid hormone, T3. Selenium deficiency may worsen the effects of iodine deficiency on thyroid function, and adequate selenium nutritional status may help protect against some of the neurological effects of iodine deficiency. Additionally, selenium-based antioxidant enzymes protect the thyroid gland from peroxides produced during the synthesis of these hormones. 2, 3, 6
Zinc, another essential mineral responsible for hundreds of critical chemical reactions in the healthy human, is also important for maintaining normal thyroid homeostasis. Its complex roles include effects on both the synthesis and mode of action of the hormones. Thyroid hormone binding transcription factors, which are essential for modulating gene expression, contain zinc bound to cysteine-related compounds. In some studies, low zinc status was associated with decreased thyroid hormone levels. 3
Copper is believed to have a role in thyroid hormone function, perhaps related to selenium status. 3
Guggul (Commiphora mukul) is an Indian Ayurvedic herb that contains the active compound Guggulsterone, which has been shown to stimulate thyroid activity. 7-8
These ingredients, both singly and as thyroid support formulas, are in demand by consumers wanting to assure adequate thyroid function in times of dietary insufficiencies and various stresses. Of course, these nutrients and their many functions in the body have a host of potential benefits to those supplementing with them if they may not get adequate amounts from their diet for their individual requirements.
- Zoeller RT, Tan SW, Tyl RW. General background on the hypothalamic-pituitary-thyroid (HPT) axis. Crit Rev Toxicol. 2007 Jan-Feb;37(1-2):11-53. Review. PubMed PMID: 17364704.
- Arthur JR, Beckett GJ. Thyroid function. Br Med Bull. 1999;55(3):658-68. Review. PubMed PMID: 10746354.