Thyroid health depends on far more than just iodine; a new review of 20 years of research reveals that selenium, zinc, iron, vitamin D, and vitamin B12 all play critical roles in preventing thyroid disease and supporting how your body uses thyroid hormones. The findings challenge the popular belief that restrictive diets like gluten-free eating help thyroid conditions, and instead point to balanced, nutrient-rich eating patterns as the key to thyroid protection .

Which Nutrients Does Your Thyroid Actually Need?

A comprehensive review published in the Journal of Endocrinological Investigation analyzed studies from 2005 to 2025 and identified specific micronutrients that directly influence thyroid function and autoimmune thyroid disease risk. While iodine has long been recognized as essential for thyroid hormone production, researchers emphasize that overall nutrition, including multiple micronutrients and dietary patterns, significantly influences thyroid health .

The research found that iodine follows a U-shaped relationship with thyroid health, meaning both deficiency and excess can cause problems. Low iodine levels may lead to hypothyroidism and goiter, while excessive intake can trigger hyperthyroidism or autoimmune thyroiditis in susceptible individuals. Beyond iodine, several other nutrients emerged as critical:

• Selenium: Supports antioxidant defenses and hormone metabolism, protecting thyroid tissue from oxidative stress and supporting the conversion of thyroid hormones into their active forms
• Zinc: Essential for enzyme activity involved in thyroid hormone production and immune system regulation, with deficiencies linked to increased thyroid dysfunction
• Iron: Required for enzyme activity in hormone production, and iron deficiency is commonly observed in people with thyroid disease
• Vitamin D: Commonly low in individuals with autoimmune thyroid conditions, though supplementation only helps when deficiencies are present
• Vitamin B12: Frequently deficient in autoimmune thyroid disease, and correcting deficiency may improve energy and cognitive symptoms

Does the Mediterranean Diet Really Protect Thyroid Health?

The review found striking differences between dietary patterns. The Mediterranean diet, rich in fruits, vegetables, whole grains, fish, and olive oil, is associated with lower inflammation and reduced thyroid autoantibodies, the immune proteins that attack thyroid tissue in autoimmune thyroid disease . This protective effect appears to come from the combination of anti-inflammatory compounds, healthy fats, and diverse micronutrients in this eating pattern.

In contrast, the Western diet, high in refined sugars, saturated fats, and processed foods, may promote inflammation, oxidative stress, and gut microbiota imbalance, increasing thyroid disease risk. The difference between these dietary patterns suggests that what you eat influences not just thyroid hormone levels, but the underlying immune processes that drive autoimmune thyroid disease .

Should You Try Restrictive Diets Like Gluten-Free Eating?

Many people with thyroid disease consider eliminating gluten or lactose, hoping to reduce symptoms. However, the research shows that restrictive diets such as gluten-free or lactose-free regimens show no clear benefit for thyroid health unless medically indicated, such as when celiac disease or lactose intolerance is confirmed. These restrictive approaches may actually cause nutrient deficiencies that worsen thyroid function .

The evidence supports a different approach. Instead of eliminating foods, the focus should be on adding nutrient-dense foods that support thyroid health. A balanced, nutrient-rich diet provides the micronutrients and anti-inflammatory compounds that support thyroid function without unnecessary restrictions.

How to Support Your Thyroid Through Nutrition

• Eat a Mediterranean-Style Pattern: Focus on fruits, vegetables, whole grains, fish, legumes, nuts, and olive oil, which provide the micronutrients and anti-inflammatory compounds that protect thyroid health
• Include Selenium-Rich Foods: Add Brazil nuts, fish, poultry, and eggs to your diet, as selenium supports thyroid hormone metabolism and antioxidant defenses
• Ensure Adequate Zinc Intake: Eat oysters, beef, pumpkin seeds, and chickpeas, which provide zinc needed for thyroid hormone production and immune regulation
• Get Enough Iron: Include red meat, poultry, beans, lentils, and fortified grains, particularly important if you have heavy menstrual bleeding or follow a vegetarian diet
• Check Vitamin D and B12 Status: Ask your doctor to test these nutrients, as deficiencies are common in autoimmune thyroid disease and supplementation may help when levels are low
• Avoid Unnecessary Restrictions: Unless you have confirmed celiac disease or lactose intolerance, avoid eliminating entire food groups, as this may create nutrient gaps that worsen thyroid health

What About Gut Health and Thyroid Disease?

The review highlighted an important connection between gut health and thyroid autoimmunity. The Western diet, high in processed foods and low in fiber, promotes gut microbiota imbalance, which is linked to increased thyroid autoimmunity and inflammation. A Mediterranean-style diet, rich in diverse plant foods, supports healthy gut bacteria that may help regulate immune responses and reduce thyroid autoimmunity .

This suggests that supporting your gut microbiota through diverse plant foods, fermented foods like yogurt and sauerkraut, and adequate fiber intake may indirectly support thyroid health by reducing the immune activation that drives autoimmune thyroid disease.

Key Takeaways for Thyroid Health

The research makes clear that thyroid health is not about finding the perfect supplement or following the most restrictive diet. Instead, it depends on consistent, balanced nutrition that provides the micronutrients your thyroid needs to function and your immune system needs to stay regulated. A Mediterranean-style eating pattern, rich in whole foods and diverse nutrients, offers the strongest evidence for protecting thyroid health and reducing autoimmune thyroid disease risk .

If you have been diagnosed with hypothyroidism or Hashimoto's disease, ask your doctor to check your levels of selenium, zinc, iron, vitamin D, and vitamin B12. If deficiencies are found, correcting them through food or supplementation may improve both thyroid function and overall health. Most importantly, focus on adding nutrient-dense foods rather than eliminating foods, unless you have a specific medical reason to avoid them.