Think of the thyroid as the gas and brake pedals on the metabolism. Depending on the level of hormones released by this butterfly-shaped gland located just below the Adam’s apple, metabolism speeds up or slows down. Far more common in the United States is hypothyroidism, when the metabolism slows.

While your staff can’t take the place of medical professionals in advising hypothyroidism treatment, which usually means taking prescription hormones, your vitamin and supplement aisle holds some key ingredients for a thriving thyroid no matter the health status of your customer. With a little know-how, you and your staff will be able to discuss this complicated condition with customers.

Hypo vs. hyperthyroidism
A properly running thyroid gland produces a steady flow of the hormone thyroxine, commonly called T4, which the body then converts to triiodothyronine, or T3, the active hormone that regulates metabolism.

Hyperthyroidism, when the thyroid produces too much T4 hormone, can make you feel hot, anxious and revved up. “The patient’s heart starts jumping out of their chest. They lose weight, have diarrhea. It can be pretty scary,” says Dean Neary, ND, a faculty member in naturopathic medicine at Bastyr University in Kenmore, Wash. Fortunately, hyperthyroidism is extremely rare, affecting only around 1 percent of all Americans, according to the National Institutes of Health.

Far more common is hypothyroidism, when the gland produces too little T4 hormone. The metabolism slows down, potentially causing the person to gain weight and to feel overly tired, constipated and depressed. Medical professionals theorize that due to hormonal fluctuations, women are more susceptible to hypothyroidism than men, and the risk increases with age.

“If a woman in her 30s, 40s or 50s experiences new-onset fatigue, weight gain, hair loss, high cholesterol—or even just two of those symptoms, I think those are good reasons to have the thyroid tested by a doctor,” says Theodore Friedman, MD, author of The Everything Guide to Thyroid Disease (ITS, 2007).

Neary says mineral deficiency and the daily onslaught of stressors we face in the modern world may play a role in the growing number of hypothyroid cases. “The thyroid gland is very sensitive to toxins, even to miniscule amounts of radiation,” he says. “Fifty years ago we weren’t all plopped in front of computer screens; maybe that’s taking a little bit of a toll as far as glandular function.”

Supplements to promote a healthy thyroid
Minerals. The mineral most often referenced with regard to thyroid function is selenium, a trace mineral found in soil and in some meat, seafood and plants—Brazil nuts may contain as much as 544 mcg per ounce. “Selenium is critical in turning the thyroid hormone into its active form,” says Jacob Teitelbaum, MD, author of From Fatigued to Fantastic (Penguin/Avery, 2007). Selenium has antioxidant properties, decreasing the free radicals (oxidants) that can block the conversion of the inactive T4 hormone to the active T3 hormone your body needs. A 2008 blind, placebo-controlled study of 132 patients with autoimmune thyroiditis, a disease in which the immune system attacks the thyroid gland, found that patients given 200 mcg of selenium combined with the amino acid methionine had far fewer anti-thyroid antibodies at the end of the study.

Neary suggests complementing selenium with other minerals, such as zinc and copper, to support overall cellular function. “In general, these minerals are essential to the biochemical pathways converting T4 to T3,” he says. According to the book Thyroid Power: 10 Steps to Total Health (Harper, 2002) by Richard Shames, MD, and Karilee Shames, PhD, RN, zinc aids the process that signals the thyroid gland to produce thyroid hormones.

Even if customers eat a balanced diet, they may still need to supplement with these minerals. Because modern agricultural practices such as over-farming and monocropping deplete soil nutrients, minerals we used to get from food grown in nutrient-rich soil are less available. “Take selenium as an example,” Neary says. “Plants aren’t getting selenium from the soil, so what we’re getting on a dietary level is not sufficient many times.”

Antioxidants. In addition to minerals, antioxidant vitamins such as C, E and the B family are key elements in thyroid function, Neary says. These vitamins are necessary for the biochemical transformations involved in manufacturing the T4 hormone and the conversion of T4 to T3. Antioxidants also protect cells from damage caused by free radicals created during the conversion process. According to Shames and Shames, the amount of antioxidants necessary for proper thyroid function may have been underestimated in the past, and they recommend a “full-symphony antioxidant,” including vitamins E and A.

Iodine. Iodine is a naturally occurring trace element found in some soils, but primarily in seafood, sea vegetables and kelp. It is also used by the body to make T4. Iodine deficiency can lead to enlargement of the thyroid gland, called a goiter. Goiters in some parts of the United States—primarily around the Great Lakes area, which was once referred to as the “Goiter Belt”—were so common that major salt producers began to iodize their products in the early 1920s.

Iodine deficiency may be a problem once again due to changes in our eating patterns. “Some populations have migrated away from excessive salt intake and have inadvertently taken away some of that iodine intake,” Neary says. “We’ve also seen people move toward more sea salts that may not contain the levels of an iodized salt.” Another key factor may be the hidden sources of our salt intake. According to the Mayo Clinic, 77 percent of the sodium in the average diet comes from prepared or processed foods and is therefore not iodized.

“The number-one deficiency when it comes to thyroid is iodine,” Teitelbaum says. “Iodine deficiency used to be epidemic in this country, and it is now becoming epidemic once again.”

L-tyrosine. Teitelbaum calls the amino acid L-tyrosine “the backbone” of the thyroid system. It is a precursor to T4, and it assists all the body’s hormone processes. According to Shames and Shames, the thyroid hormone is basically tyrosine plus iodine.

Cara Hopkins is an Austin, Texas-based freelance writer.