Your thyroid is the main gland in your body responsible for the regulation of two important hormones known as T3 and T4. The thyroid is one of several glands involved in regulating your body's metabolism. The glands in question require several amino acids, vitamins and minerals to produce the necessary regulatory hormones, one of which is zinc. Zinc is involved in the synthesis of several hormones related to cell metabolism. A deficiency in this hormone can have a significant effect on your health.
The Thyroid Gland and Zinc
The thyroid is a gland located at the front of your neck just below the larynx. Thyroid tissue is the only tissue capable of absorbing iodine from your diet and uses this iodine in conjunction with the amino acid tyrosine to produce the regulatory hormones T3 and T4. T3 and T4 regulate cellular metabolism and, under normal conditions, the T3 to T4 ratio is about four T3 hormones for every one T4 due to the potency of the T3 hormone. The body can convert T4 to T3 when needed. Zinc is an important mineral in the conversion process. It interacts with the enzyme deiodinase, which removes the iodine from T4, which will turn the hormone into a T3 molecule.
Pituitary Gland and Zinc
The pituitary gland controls the actions of the thyroid. It is located at the base of the brain and is about the size of a quarter. When it senses that the level of T3 and T4 are too low, it releases a hormone called thyroid-stimulating hormone, or TSH. The pituitary glad has a a negative feedback system that will shut off TSH production as it senses rising levels of T3 and T4 in the bloodstream. In this case, zinc has a more indirect, but potent, effect on the thyroid. Zinc is involved in the regulation of TSH through the negative feedback system.
Effects of Zinc Deficiency
The effects of zinc deficiency are rather marked and can vary slightly depending on your age. During the growing years of a person's life, zinc deficiency will result in stunted growth due to the fact that your body cannot efficiently convert T4 to T3 when needed, leaving it stranded when it needs to increase its metabolic capabilities and stimulate growth of new cells. During the adult years, zinc deficiency can lead to a case of hyperthyroidism. In hyperthyroidism, the lack of zinc stops the regulation of TSH through feedback and causes too much TSH to be produced. This can lead to your heart racing, an increase in blood pressure and fever.
Zinc Supplementation and Considerations
The Food and Drug Administration recommends 11 milligrams per day for men and 8 milligrams for women. You can achieve this level either through supplementation or by eating foods such as beef, pork, chicken and beans. Oysters also have a large amount of zinc as well. Be careful of eating raw oysters as you run the risk of contracting a food-borne illness. Too much zinc can also be a detriment, causing anemia, low copper levels and poor immune function. It is also reported that excess zinc can decrease the absorption of antibiotics and other drugs. The FDA recommends no more than 40 milligrams of zinc per day to avoid these problems.
References
- "Thyroid Power"; Richard Shames, M.D. and Karilee Shames, Ph.D., R.N.; May 2002
- National Institutes of Health: Zinc
- Endocrine Web: How Your Thyroid Works
- "Acta Physiologica, Pharmacologica et Therapeutica Latinoamericana"; Changes Introduced by Zinc in Thyroxine Deoiodination by Rat Liver In Vitro and In Vivo; Pondal M. Gonzalez et al.; 1995
- American Cancer Society: Zinc
