The current article is content from dr. Shishkov, endocrinologist. It provides information on new aspects related to nutrition in autoimmune thyroid diseases.

The question of what the diet should be in autoimmune thyroid diseases has been addressed in numerous clinical studies. However, there is no definite and definitive answer to what is the most appropriate diet for Hashimoto's.

Adequate availability and metabolism of three essential trace elements - iodine, selenium and iron - provide the necessary conditions for the functioning and action of the thyroid hormone system in humans and vertebrates. An imbalance between the thyroid content of these elements challenges the negative feedback regulation of the hypothalamus-pituitary-thyroid axis, causing or facilitating common diseases associated with abnormal thyroid hormonal status, such as autoimmune thyroid diseases and metabolic disorders.

The association of some micronutrients with autoimmunity determines the studies conducted in the field as well as the resulting recommendations for nutrition in Hashimoto's disease.

Iron (Fe)

The relationship of iron (Fe) to thyroid hormone biosynthesis and thyroid function is also categorical [12]. Inadequate Fe supply can impair hormone production even with sufficient iodine supply. Women of reproductive age are particularly vulnerable to this constellation given their monthly iron loss during menstruation. (Köhrle et al. 2023)

Anemias associated with iron deficiency may be associated with hypothyroidism. Iron is an important part of the enzyme tyroperoxidase (TPO) (Luo et. al. 2021) In the presence of autoantibodies, iron deficiency can further impair thyroid function. For this reason, iron deficiency needs to be targeted and treated in Hashimoto's thyroiditis. Intake of iron-containing foods is an important element of proper nutrition in Hashimoto's.

In Hashimoto's thyroiditis, iron deficiency needs to be purposefully sought and treated.

Selenium (Se)

Selenium deficiency impairs thyroid function and TH production and secretion, and various studies are examining whether and which thyroid hormone-related disorders can be prevented or treated by (supplemental) dietary Se supply or Se-containing drugs. (Winther et al. 2020)

Thyroid function disorders have been found to be more common in regions with low selenium (Se) intake. At lower selenium levels higher anti-TPO values were found. There is evidence that selenium replacement may have an effect on TSH and anti-TPO values. (Huwiler et al. 2024) Despite these data, there is no definitive scientific evidence that selenium (Se) supplementation is recommended for Hashimoto's thyroiditis.

What direct implications might this information have on our nutrition in Hashimoto's? 

In view of these data, diets poor in selenium (Se) should be avoided. These are vegan diets, as they exclude the main sources of selenium - meat and dairy products.

Best food sources of selenium:

• Brazil walnuts
• tuna
• oysters
• sardines
• lobster
• liver
• beef
• sunflower seeds
• eggs

Adequate selenium intake is important in thyroid autoimmunity.

Iodine

The need of iodine for the proper function of the thyroid gland has been known for a long time, since a century ago iodine prophylaxis was started in Bulgaria. However, a decrease in the production and consumption of iodine in salt is reported, especially in the more developed regions of the world and Western Europe. (Zimmeramman et. al. 2021) In addition to non-iodized salt, paleo diets also require limiting some of the major sources of iodine. (Manousou S et al. 2017)

Foods rich in iodine: 

• Seaweed
• Fish
• Ракообразни
• Dairy products
• Eggs
• Iodized salt
• Liver
• Prunes

Adequate dietary iodine intake is key to proper thyroid function.

Mediterranean diet

Several studies have focused on diet and eating patterns ("too much", "too fatty", "too salty", "too sweet") as risk factors for the development of autoimmune diseases in Western societies and have consistently shown that these dietary characteristics are risk factors for autoimmune diseases, including Hashimoto's thyroiditis. (Ruggeri et. al 2023)

The Mediterraneanrx diet may be protective for Hashimoto's autoimmune thyroiditis. For comparison, we can see an example from the scientific literature that societies consuming more meat and meat products have a higher incidence of Hashimoto's thyroiditis. (Kaličanin D. et al. 2020)

Thanks to its nutritional components, the Mediterranean diet has a positive impact on the intestinal microflora, redox homeostasis and immune system function, in contrast to the Western diet, and can be proposed for the prevention and treatment of autoimmune thyroid disorders (a "precision nutrition" approach).

Ruggeri RM, et. al. Autoimmune Thyroid Disorders: The Mediterranean Diet as a Protective Choice. Nutrients. 2023 Sep 12;15(18):3953. doi: 10.3390/nu15183953.

Hashimoto's nutrition tips:

In conclusion, the following recommendations can be made when tailoring your Hashimoto's diet:

• Iron deficiency search and replacement.
• Avoid a diet leading to iodine deficiency (e.g. Himalayan salt).
• Vitamin D and selenium can be taken in patients with proven deficiency.
• The Mediterranean diet has a beneficial effect on autoimmunity in Hashimoto's thyroiditis.
• There is a lack of definitive evidence for the benefits of a gluten-free diet.

If you need to be examined, diagnosed or treated for Hashimoto's thyroiditis, we recommend that you see an endocrinologist. At SanaMedic we have a team of endocrinologists.