Dietary Guidance for Hashimoto’s Thyroiditis

In 2019 I was asked by Medscape for my opinion and thoughts regarding “autoimmune protocol” dietary strategy for patients with hashimoto’s hypothyroidism. The author of that article has hashimoto’s herself but was telling a story of a colleague who has hashimoto’s and is trying to delay hypothyroidism through dietary efforts. In addition to reading that article here, I figured I would publish everything I wrote for them as obviously only some snippets were included. I’ve also written in the past on the concern of gluten and thyroid health. In late 2020, another study was published, creating media attention, suggesting low animal intake in the context of a Mediterranean diet may be beneficial.

Karl Nadolsky, DO FACE

Diplomate, American Board of Obesity Medicine

• Hashimoto’s autoimmune thyroiditis is the most common cause of primary hypothyroidism in the United States and other iodine-sufficient areas due to anti-body-mediated destruction of thyroid cells.
  • Genetic susceptibility with environmental triggers seems to be the key factor though the triggers are not fully elucidated. Infections, stress, pregnancy, iodine intake and radiation exposure are known potential contributors. Some people feel that poor dietary habits, especially a western diet that is “pro-inflammatory” may be a primary culprit.
  • Iodine deficiency is a common cause world-wide and there are case reports, including an anecdotal patient of mine, who have become hypothyroid due to an “organic” vegan diet without any iodized salt.
• Selenium is a critical mineral for thyroid function and some data suggests that supplementation may decrease antibodies, especially in selenium-deficient areas. One meta-analysis did result in reduced, albeit not resolved, thyroid-peroxidase antibodies but without any effects on thyroid hormone levels while another meta-analysis found no improvement in hormone levels, quality of life or changes in thyroid ultrasound for those who were without thyroid hormone replacement.
• Some observational studies have brought up the potential of vitamin D’s role in autoimmune thyroid disease and a meta-analysis of vitamin D supplementation did show potential lowering of thyroid peroxidase and thyroglobulin antibodies but not in a clinically meaningful way thus unclear benefits.
• Iron deficiency impairs thyroid metabolism and is more common in hashimoto’s due to autoimmune gastritis while iron therapy seems to improve thyroid hormone status in treated patients.
• Stress reduction therapy may be of benefit, even in reducing antibody levels, and more importantly in reducing depression and anxiety.
• “Autoimmune diseases run together” thus those with hashimoto’s are also at increased risk of celiac disease. It has been proposed that a gluten-free diet will help or even resolve hashimoto’s, even without celiac disease. Some data do show that some people in the small subset of those with both celiac and hashimoto’s, the gluten-free diet will improve thyroid antibody levels and has been suggested due to the strong relationship.
• There have been several books written suggesting that diets like “Paleolithic” diets or “autoimmune protocol” diets can help reduce inflammatory triggers and thus hashimoto’s autoimmune thyroid disease but often vilify whole grains, soy and dairy despite some of the known health benefits of those foods. The real key seems to be improving dietary patterns away from highly refined or processed and calorically dense dietary patterns like the “standard American diet” (SAD) to a more “whole food” pattern diet which is fundamental for most healthful dietary change. There was a small trial recently comparing the “SAD” to an online lifestyle coaching program and “autoimmune protocol” diet lower in many refined/processed western foods, dietary additives and nutrient-dense whole foods such as vegetables, fruits, nuts/seeds, tubers, wild game/poultry and non-processed meats. This small trial did show the expected improvements in quality of life but without any changes to thyroid function or antibodies.
• The cross-sectional study from 2020 looked at dietary habits and their relationship with thyroid autoimmunity. Of 200 subjects, 81 (71 females and 10 males) had Hashimoto’s thyroiditis and the remaining 119 (102 females and 17 males) served as controls but all had normal thyroid hormone levels/function. Dietary questionnaires suggested higher intake frequencies of animal foods in those with hashimoto’s compared with controls, who reported higher intake frequencies of plant foods (legumes, fruits and vegetables, nuts). Meat consumption was associated with increased odds of thyroid autoimmunity, while the Mediterranean diet traits were protective. This is interesting but overall unclear utility based upon how the study was done. It certainly doesn’t show us if plant-based mediterranean dietary habits are truly protective or therapeutic like an actual trial would. Certainly, as noted below, it does support our efforts to encourage more whole-foods, especially plants, with a “Mediterranean” pattern in our patients’ dietary habits.
• Anecdotally, I and many other clinicians, have evaluated patients with hashimoto’s autoimmune thyroiditis and hypothyroidism who have improved their dietary habits and gone to the extreme of adhering to a proposed “autimmune protocol.” I, nor any of my colleagues, have had any patients succeed in reducing antibody levels to a clinically significant degree or not needed thyroid hormone replacement if already on it. That said, we certainly do encourage improved dietary habits which include more vegetables, fruits, legumes/pulses, nuts/seeds, fish, poultry and unprocessed meats along with exercise, sleep hygiene and stress reduction as those are definitively evidence-based therapies for everyone, especially those with hashimoto’s.