Thyroid Diet: What to Eat, What to Skip

If your thyroid is underactive or you have an autoimmune condition like Hashimoto's, food can help you feel better — or make symptoms worse. This guide gives clear, usable tips: the nutrients your thyroid needs, which foods to favor, what to limit, and simple timing rules if you take thyroid medicine.

Key nutrients and where to get them

Iodine: Needed to make thyroid hormones. Use iodized salt in moderation and eat seafood or dairy if you tolerate them. Don’t overdo seaweed — a sheet of kelp can contain a lot of iodine and too much can cause problems, especially with autoimmune thyroid disease.

Selenium: Helps convert and activate thyroid hormone and supports the immune system. One or two Brazil nuts a day often covers needs. Seafood, eggs, and sunflower seeds also help.

Iron and zinc: Iron is needed for hormone production; low iron can worsen fatigue. Eat lean red meat, poultry, or iron-rich plant foods (spinach, lentils) with vitamin C to boost absorption. Zinc comes from shellfish, meat, and pumpkin seeds and supports hormone balance.

Foods to limit and timing tips

Goitrogens: Raw cruciferous vegetables (broccoli, kale, cabbage, Brussels sprouts) contain substances that can interfere with thyroid function when eaten in very large amounts. Cooking cuts most of that effect. You don’t need to avoid these veggies — cook them and vary portion sizes.

Soy and high-soy diets can affect thyroid hormone absorption and function for some people. If you take levothyroxine, avoid large soy meals close to your medication. A small amount of soy food is usually fine.

Calcium, iron supplements, and some antacids block levothyroxine absorption. Take your thyroid medicine 30–60 minutes before breakfast or wait at least 4 hours after taking supplements or calcium-rich meals.

Gluten: Some people with Hashimoto's feel better on a gluten-free trial. If you suspect a link, ask your clinician about testing or a short elimination period rather than self-diagnosing.

Other tips: limit processed sugar and excess simple carbs — they can worsen weight and energy issues. Stay hydrated and include fiber for constipation, but again space fiber-heavy meals from your thyroid pill.

Practical swaps: choose iodized salt over fancy sea salts, add a Brazil nut for selenium instead of a supplement if you prefer food sources, and pair iron plant foods with a squeeze of lemon to help absorption.

Talk to your clinician before making big diet changes or starting supplements. Small, consistent changes — better protein at breakfast, mindful timing of medication, and a couple of nutrient-focused swaps — often make the biggest difference for thyroid symptoms.