A healthy diet means eating a variety of foods in the correct proportions which is not always easy to follow. Some foods or supplements could impact thyroid function or alter the results of hormonal investigations. Therefore, it is worth it to know:

Iodine

Iodine it’s essential for thyroid hormonal synthesis. Less iodine or too much iodine however could cause hormonal deficiency or overactive thyroid. Diet reach of iodine could alter thyroid hormone synthesis. Supplements could be useful if you are pregnant or have an underactive thyroid but unnecessary for example if you are on treatment for overactive thyroid. Food rich in iodine includes cheese, milk, iodized table salt, saltwater fish, seaweed, and whole eggs.

Zink

Zink is necessary for adequate thyroid hormonal synthesis. A deficiency of Zink could be associated with an underactive thyroid and excessive hair loss. In most cases, there is no need to take extra supplements if you are on a healthy diet. For adults, the recommended daily dosage is typically 15–30 mg of elemental zinc, and intake of higher doses should be monitored. Food rich in Zn includes shellfish, beef, chicken, and legumes (e.g., beans, chickpeas, lentils.

Brassicas

It is thought that Brassicas may contribute to the formation of goiter (swelling or enlargement of the thyroid gland), but consumption would need to be very high. Therefore, it is not usually a problem. Brassicas include cabbage and cauliflower.

Selenium

Selenium is important to maintain normal thyroid function and reduce oxidative stress. Some studies suggest positive effects with support of Selenium supplements in specific groups of patients with autoimmune thyroiditis. It is known to have therapeutic effects for people with mild thyroid eye disease. Excessive intake however should be avoided as too much Selenium could have toxic effects. Most of the Selenium is obtained from a healthy diet consuming: seafood (e.g., tuna, sardines, shrimps), meat (e.g., ham, beefsteak, turkey, beef liver, chicken), cereals, grains, and crops (e.g., pasta, brown rice, whole-wheat bread), milk or dairy products (e.g., cottage cheese, milk, eggs), fruit/vegetables (e.g., spinach, bananas). The food with the highest Selenium content is Brazil nuts but different brands could contain different amounts of selenium.

Gluten

People intolerant to gluten present with abdominal discomfort after consuming bread or other gluten-containing products. The condition is known as celiac disease and is also autoimmune and could be associated with Hashimoto’s thyroiditis. Some research suggests that removing gluten from the diet could improve thyroid function in patients with Hashimoto thyroiditis. Gluten is a protein in wheat and other grains, including barley, oats, and rye.

Biotin

Biotin is part of multivitamins or could be taken as additional supplements. It can not alter but could interfere with thyroid function test results. It must be stopped at least 3 days prior to the blood test to avoid misleading blood test results.

Food or supplements interfere with thyroid medications, especially levothyroxine. Therefore, should be taken or consumed in intervals 2-4 hours apart from milk or calcium supplements, Iron supplements, antacids, High-fibre foods such as bran flakes, fiber bars or drinks, and soy-based foods.