The Best Foods for Thyroid Health: What to Eat and What to Avoid

Your thyroid is a small but mighty gland that plays a central role in nearly every aspect of your health. From regulating metabolism and energy levels to supporting growth, development, and mood, the thyroid’s influence is far-reaching. When thyroid function is disrupted, it can leave you feeling fatigued, struggling with weight, battling brain fog, or experiencing digestive and mood challenges.

Hypothyroidism, or an underactive thyroid, is increasingly common, yet many people remain unaware they are affected. While standard treatment often focuses solely on hormone replacement, addressing only the symptoms may not fully restore optimal thyroid function. Nutritional support, lifestyle adjustments, and an understanding of foods that nourish—or stress—the thyroid can make a meaningful difference in your energy, health, and overall well-being.

In this article, we explore the nutrients your thyroid needs, the foods that promote healthy thyroid function, and which foods to approach with caution to support long-term thyroid health.

The information in this blog post is for educational purposes only and, therefore, is not intended to be used to diagnose or substitute medical advice or treatment. You should always consult your medical doctor if you intend to make changes based on this information and you should never disregard medical advice or cease taking medication because of it.

Foods That Support Healthy Thyroid Function

The thyroid relies on specific nutrients to produce hormones efficiently, and deficiencies in these nutrients are often linked to thyroid dysfunction. Here’s a breakdown of key nutrients and their food sources:

• Vitamin D – Found in fish, eggs, mushrooms, and through sunlight exposure. One study reported a 72% higher prevalence of vitamin D deficiency in individuals with autoimmune thyroid disease compared to healthy individuals.

• Iron – Found in spinach, red meat, shellfish, organ meat, legumes, broccoli, and pumpkin seeds. Iron supports thyroid enzymes that convert T4 into the more active T3 and can enhance iodine supplementation effectiveness.

• Iodine – Found primarily in seafood. Around 25% of vegetarians and 80% of vegans are iodine deficient. However, excess iodine can contribute to hypothyroidism, so balance is key.

• Selenium – Found in Brazil nuts*, fish, turkey, beef, eggs, and sunflower seeds. Selenium boosts T4-to-T3 conversion, supports iodine utilization, and plays an antioxidant role. Research shows it can reduce thyroid autoantibodies, especially when used alongside thyroid medication.

• Zinc – Found in meat, shellfish, nuts, seeds, legumes, eggs, whole grains, and dark chocolate. Zinc supports T4-to-T3 conversion and improves cellular sensitivity to thyroid hormone.

• Vitamin A – Found in vegetables like sweet potatoes, broccoli, carrots, peppers, and spinach. Vitamin A increases iodine uptake and is essential for producing thyroid proteins.

• Vitamin B2, B3, B6 – Found in meat, fish, eggs, dark leafy greens, and sunflower seeds.

• Tyrosine – Found in high-protein foods, nuts, seeds, cheese, eggs, and beans. Tyrosine is required to produce thyroid hormone.

*A note on nutrient balance: Some nutrients, particularly iodine and selenium, can be harmful in excess. For example, a single Brazil nut can contain 68–91 micrograms of selenium—meeting or exceeding the recommended daily allowance of 55 micrograms. Stick to recommended daily amounts unless advised otherwise by a healthcare professional. For most people, however, increasing intake of these nutrient-rich foods is beneficial.

Foods to Approach With Caution in Hypothyroidism

Thyroid function can be affected not just by nutrient deficiencies, but also by imbalances or sensitivities to certain foods. Here’s what to watch out for:

Calorie Restriction – Extremely low-calorie diets can reduce levels of active thyroid hormone (T3). Intermittent fasting can be beneficial if done correctly, but long-term calorie restriction signals the body to slow metabolism. Timing meals strategically (like early dinners and later breakfasts) may offer better results than simply reducing calories.

Carbs and Sugar – Low-carb diets can reduce T3 levels, while high insulin levels and insulin resistance are linked to hypothyroidism. The type of carbohydrate matters: refined carbs and sugar raise cortisol and impair thyroid function, whereas complex carbs, particularly leafy greens, support thyroid health.

Goitrogens – Found in soy, broccoli, cauliflower, sweet potatoes, and dark leafy greens, goitrogens may block iodine uptake in lab studies. Human studies are inconclusive, but consuming these foods cooked rather than raw may reduce any potential negative effects.

Food Sensitivities – Individual responses vary, but gluten and dairy can trigger inflammation that reduces thyroid hormone levels. Autoimmune thyroid disease and type 1 diabetes are common in people with celiac disease. Even non-celiac gluten sensitivity may contribute to autoimmune thyroid disease. Research shows that some individuals with subclinical hypothyroidism normalized their thyroid markers after adopting a gluten-free diet. Elimination diets and food sensitivity testing can help identify triggers.

This approach emphasizes the importance of both including nutrient-rich foods and avoiding or moderating foods that may hinder thyroid function. By focusing on diet as part of a holistic strategy, you can better support thyroid health and overall well-being.