Hashimoto’s Thyroiditis: Exploring the Role of Diet in Managing Autoimmune Thyroid Disease

Hashimoto’s Thyroiditis is an autoimmune thyroid diseases (AITD) mediated by immune cells and antibodies, TPOAb and TgAb, leading to the destruction of the thyroid cells.  The disease usually results in a decline in hormone production (hypothyroidism).

Dysbiosis is Implicated in Hashimoto’s Disease

A case control study found that the gut microbiota of Hashimoto’s patients differs from that of healthy individuals, but the gut microbiota of Hashimoto’s patients is very similar to each other and is correlated with clinical symptoms. [1]

The use of antibiotics affects gut microbiota [2], and there are many patients who suffer from both gut diseases and AITD (autoimmune thyroid diseases).

A 2020 research paper from Austria highlighted the connection between the gut and AITD, showing that Hashimoto’s and Graves’ diseases are often associated with celiac disease or gluten intolerance. Intestinal permeability allows antigens to enter the bloodstream, triggering the immune system. Gut microbiota and environment impact the absorption of essential trace nutrients for thyroid function, such as iodine, iron, copper, and selenium. AITD patients commonly experience trace nutrient deficiencies, indicating the significant gut-AITD relationship [3].

Dietary Factors Affect Hashimoto’s Disease

Soy Products

Soy products can affect thyroid medication absorption [4,5] due to the presence of isoflavones, especially genistein, which inhibits crucial thyroid peroxidase (TPO) activity [6]. Research on mice consuming large soy product doses revealed a 50% decrease in TPO function in the blood, yet they did not experience hypothyroidism, suggesting soy products didn’t cause hypothyroid symptoms in mice. A clinical trial involving Hashimoto’s thyroiditis patients [7] found that continuous consumption of isoflavones (genistein) for one month resulted in increased T4 and Ft4 levels, decreased TSH, TPOAb, TgAb, and inflammation, indicating potential benefits in improving thyroid function and reducing immune system stress.

Cruciferous Vegetables

Cruciferous vegetables contain goitrogens that may affect thyroid hormone production due to glucosinolates interfering with iodine absorption. While animal experiments have shown suppressed thyroid function, human clinical studies haven’t shown similar effects [8]. For Hashimoto’s patients, a controlled clinical study with 45 women found that consuming a beverage containing broccoli sprout extract (rich in glucosinolates) for 84 days did not impact thyroid function [9]. Most functional medicine practitioners believe cruciferous vegetables are generally safe for Hashimoto’s thyroiditis, as they contain organic sulfur antioxidants that can help reduce inflammation. If concerned about goitrogens, cooking the vegetables before consumption further reduces the risk [8, 10,11].

Meat and Dairy Diet

A study found that Hashimoto’s patients had a higher consumption of red meat and dairy products, while the healthy control group consumed more vegetables and poultry. The study also found that the Mediterranean diet may have a protective effect on AITD, and reducing animal based diets may reduce oxidative stress and have a protective effect on Hashimoto’s patients. [12]

Gluten-Free Diet

 A study in 2018 examined 16 Hashimoto’s patients who followed a gluten-free diet for six months. Patients had reduced thyroid antibodies, slightly increased vitamin D levels compared to the control group, and improved SPINA-GT (thyroid’s maximum secretion capacity) index, which is associated with TPOAb and TgAb autoantibodies. However, the gluten-free diet did not significantly improve thyroid function in the intervention group. Gluten-free diet may have clinical benefits for patients with Hashimoto’s Disease [13].

AIP Diet

A 2019 study with 17 female Hashimoto’s patients, following the Autoimmune Protocol (AIP) Diet for 10 weeks, showed no significant improvement in thyroid-related indicators and autoantibodies. However, there was a 29% decrease in the inflammation marker CRP, and an improvement in health-related quality of life (HRQL). The study suggested that providing guidance on the AIP Diet may improve inflammation markers and HRQL in female Hashimoto’s patients [14].

Artificial Sweeteners

A 2018 case study highlighted a 52-year-old female Hashimoto’s patient who consumed “sugar-free” beverages daily for three years, resulting in hypothyroidism symptoms with elevated TSH and reduced T3 and T4 levels, along with increased TPOAb autoantibodies. Stopping the intake of these beverages led to a quick return to normal thyroid function and TPOAb levels [15].  

Animal experiments indicate that artificial sweeteners can negatively impact thyroid function, reducing T3 and T4 levels [16].

The metabolites of sweeteners like aspartame have also been found to suppress thyroid cells and lower T3 and T4 levels [17].

Low-Carb Diet

In a 2016 clinical trial involving 180 Hashimoto’s patients, a low-carbohydrate diet was implemented, comprising 12%-15% carbohydrates, 50%-60% protein, and 25%-30% fat, along with plenty of leafy vegetables. After three weeks, the patients not only lost weight but also showed a significant decrease in TSH and various thyroid autoantibodies [18].

Summary

Hashimoto’s Thyroiditis is an autoimmune thyroid disease characterized by the immune system attacking thyroid cells, leading to hypothyroidism (reduced hormone production).

The gut microbiota plays a role in Hashimoto’s Disease, with dysbiosis being linked to the condition. Antibiotics and gut diseases may also affect AITD.

Dietary factors can impact Hashimoto’s Disease:

• Soy products could potentially help improve thyroid function.
• Cruciferous vegetables contain goitrogens, but evidence suggests they are generally safe for Hashimoto’s patients.
• A diet higher in red meat and dairy may be associated with Hashimoto’s, while a Mediterranean diet may offer protection.
• A gluten-free diet may have clinical benefits for Hashimoto’s patients.
• The Autoimmune Protocol (AIP) Diet may improve inflammation markers and quality of life for some patients.
• Artificial sweeteners may negatively impact thyroid function and should be used with caution.

Low-carb diets have shown positive effects on thyroid autoantibodies and weight loss in Hashimoto’s patients.

Understanding these dietary factors and their impact on Hashimoto’s Disease can help patients make informed choices to manage their condition effectively.