The thyroid is a butterfly-like gland located in the front of the neck. It produces the hormones T3 (triiodothyronine) and T4 (thyroxine). These hormones help the body use the energy it receives from the diet, balance body temperature and keep the brain, heart and other organs functioning properly. But when thyroid hormones are produced in large or small quantities significant problems can arise.

T3 is the biologically active thyroid hormone and is essential for the development of the central nervous system in fetuses and infants. T4 is a precursor hormone that is converted to T3 and its production is under strict biological control. To produce its hormones, the thyroid gland uses the iodine we get from the diet while the gland function is regulated by the thyroid-stimulating hormone (TSH).

What is hyperthyroidism?

Hyperthyroidism is the overproduction of thyroid hormones. Treatment of this condition is necessary because the body is exposed to high levels of hormones and this causes tissue damage, heart problems and bone loss. Symptoms of hyperthyroidism include weight loss, increased appetite, anxiety, irritability and nervousness, difficulty sleeping, fever, rapid heartbeat, fatigue, brittle hair, changes in menstruation, swollen urethra and swollen thyroid gland.

Some types of hyperthyroidism can be genetic. Also, Graves’ disease, an autoimmune disease, is the most common cause of hyperthyroidism and is 7-8 times more common in women than in men. It is due to antibodies produced by the body against the thyroid, which act like the thyroid hormone, ie they activate in the gland causing it to produce more hormones. There are special treatments that help balance an overactive thyroid and in some cases, treatment may include radiotherapy or gland surgery. Proper nutrition can also help.

Hyperthyroidism and diet

Iodine

The thyroid gland absorbs iodine from the blood and uses it to produce its hormones. When it produces an increased amount of hormones, it absorbs more iodine. It has been observed that the consumption of excess iodine from the diet is associated with disorders such as hyperthyroidism, autoimmune thyroid disease and the formation of nodules. So if you have these conditions you should follow a diet low in iodine.

For adults, the recommended daily dose of iodine is 150 mcg (micrograms). For pregnant women it is 220 mcg and for breastfeeding women it is 290 mcg [1]. The safe upper daily iodine intake is 1.1 mg. One teaspoon of iodized salt provides 280 micrograms of iodine and 1 gram of seaweed contains about 2 mg of iodine [2]. Some fish and seafood have enough iodine e.g. a cooked portion of 150 gram koli provides 300 mcg of iodine. In addition to seafood, dairy products also have a lot of iodine, e.g. a Greek yogurt has 115 mcg of iodine.

Nitrates and nitrites

There is concern that certain substances called nitrates and nitrites may adversely affect the thyroid gland. They are known to affect the thyroid gland in animals. These are molecules that contain nitrogen and oxygen – nitrates have 1 molecule of nitrogen and 3 molecules of oxygen (NO3) while nitrites have 1 molecule of nitrogen and 2 molecules of oxygen (NO2). Nitrates are naturally present in some plant foods, such as beets, lettuce, spinach, cabbage and radish while nitrites are found in processed meats such as sausages, bacon, and salami.

However, there is not much evidence to confirm the negative role of nitrates and nitrites in humans. In 2015 a meta-analysis of published studies found no association of nitrates with either hyperthyroidism or hypothyroidism. A recent study in which volunteers consumed 140 ml of beetroot juice for a week found no effect on thyroid hormone production [3].

Selenium

Certain minerals, especially selenium, are essential for thyroid function. The thyroid gland is among the tissues with the highest selenium content, similar to other endocrine organs. Selenium is an integral part of selenoproteins and critical enzymes in the synthesis of thyroid hormones [4]. Also, a key role is to reduce oxidative stress. So, foods rich in selenium can help balance thyroid hormone levels and protect the thyroid. Good sources of selenium are Brazilian pistachios, chia seeds, mushrooms, meat and sunflower seeds.

Hyperthyroidism causes weak and brittle bones, so vitamin D and calcium are essential to protect your bones.

At Vita4you.gr you will find a variety of selenium supplements!

References

1. Iodine.
2. Diet and thyroid – myths and facts.
3. Effect of high-nitrate beetroot juice consumption on thyroid gland hormones and iodine levels in adults.
4. Selenium and Thyroid Disease: From Pathophysiology to Treatment.