Hypothyroidism is a condition in which the body doesn’t make enough thyroid hormones. Thyroid hormones help control growth, cell repair, and metabolism. As a result, people with hypothyroidism may experience tiredness, hair loss, weight gain, feeling cold, and feeling down, among many other symptoms.

Hypothyroidism affects 1–2% of people worldwide and is 10 times more likely to affect women than men. Foods alone won’t cure hypothyroidism. However, a combination of the right nutrients and medication can help restore thyroid function
and minimize your symptoms.

This article outlines the best diet for hypothyroidism, including which foods to eat and which to avoid — all based on research.

What is hypothyroidism?

The thyroid gland is a small, butterfly-shaped gland that sits near the base of your neck. It makes and stores thyroid hormones that affect nearly every cell in your body.

When the thyroid gland receives a signal called thyroid-stimulating hormone (TSH), it releases thyroid hormones into the bloodstream. This signal is sent from the pituitary gland, a small gland found at the base of your brain, when thyroid hormone levels are low.

Occasionally, the thyroid gland doesn’t release thyroid hormones, even when there is plenty of TSH. This is called primary hypothyroidism and the most common type of hypothyroidism.

Approximately 90% of primary hypothyroidism is caused by Hashimoto’s thyroiditis, an autoimmune disease in which your immune system mistakenly attacks your thyroid gland.
Other causes of primary hypothyroidism are iodine deficiency, a genetic disorder, taking certain medications, and surgery that removes part of the thyroid.

Other times, the thyroid gland doesn’t receive enough TSH. This happens when the pituitary gland is not working properly and is called secondary hypothyroidism.


How does hypothyroidism affect your metabolism?

The thyroid hormone helps control the speed of your metabolism. The faster your metabolism, the more calories your body burns at rest. People with hypothyroidism make less thyroid hormone.

This means they have a slower metabolism and burn fewer calories at rest. Having a slow metabolism comes with several health risks. It may leave you tired, increase your blood cholesterol levels, and make it harder for you to lose weight.

If you find it difficult to maintain your weight with hypothyroidism, try doing moderate or high intensity cardio. This includes exercises like fast-paced walking, running, hiking, and rowing.

Research shows that moderate to high intensity aerobic exercise may help boost your thyroid hormone levels. In turn, this may help speed up your metabolism.

People with hypothyroidism might also benefit from increasing protein intake. Research shows that higher protein diets help increase the rate of your metabolism.



Which nut rients are important?
Several nutrients are important for optimal thyroid health.

Iodine is an essential mineral that is needed to make thyroid hormones. Thus, people with iodine deficiency might be at risk of hypothyroidism Iodine deficiency is very common and affects nearly one-third of the world’s population. However, it’s less common in people from developed countries, where iodized salt and iodine-rich seafood is widely available.

If you have an iodine deficiency, consider including more iodine-rich foods like seaweed, fish, dairy, and eggs in your meals.

Iodine supplements are unnecessary, as you can get plenty of iodine from your diet. Some studies have also shown that getting too much of this mineral may damage the thyroid gland.

Selenium helps “activate” thyroid hormones so they can be used by the body. This essential mineral also has antioxidant benefits, which means it may protect the thyroid gland from damage by molecules called free radicals.

Adding selenium-rich foods to your diet is a great way to boost your selenium levels. This includes Brazil nuts, tuna, sardines, eggs, and legumes.

However, avoid taking a selenium supplement unless advised by a healthcare professional. Supplements provide large doses, and selenium may be toxic in large amounts.

Like selenium, zinc helps the body “activate” thyroid hormones Studies also show that zinc may help the body regulate TSH,
the hormone that tells the thyroid gland to release thyroid hormones.

Zinc deficiencies are rare in developed countries, as zinc is abundant in the food supply.

Nonetheless, if you have hypothyroidism, aim to eat more zinc rich foods like oysters and other shellfish, beef, and chicken.


What foods to eat?
There are plenty of food options if you have hypothyroidism, including:

Eggs: whole eggs are best, as much of their iodine and selenium are found in the yolk, while the whites are full of protein
Meat: all meats, including lamb, beef, chicken, etc.
Fish: all seafood, including salmon, tuna, halibut, shrimp, etc.
Vegetables: all vegetables — cruciferous vegetables are fine to eat in moderate amounts, especially when cooked
Fruits: berries, bananas, oranges, tomatoes, and other antioxidant rich fruits.
Gluten-free grains and seeds: rice, buckwheat, quinoa, chia seeds, and flax seeds
Dairy: all dairy products, including milk, cheese, yogurt, etc.
Beverages: water and other non-caffeinated beverages

People with hypothyroidism should aim to eat a diet based on vegetables, fruits, and lean meats. These are low in calories and very filling, which may help prevent weight gain.


Which nutrients are harmful?
Several nutrients may harm the health of those with hypothyroidism.

Goitrogens are compounds that may interfere with the normal function of the thyroid gland.

They get their name from the term goiter, which is an enlarged thyroid gland that may occur with hypothyroidism.

Surprisingly, many common foods contain goitrogens, including
• Soy-based food: tofu, tempeh, edamame beans, soy milk
• Starchy vegetables: sweet potato, cassava
• Certain vegetables: cabbage, broccoli, kale, cauliflower, spinach
• Certain fruits: peaches, pears, strawberries
• Nuts & seeds: millet, pine nuts, peanuts
• Beverages: coffee, green tea, alcohol

In theory, people with hypothyroidism should avoid goitrogens. However, this only seems to be an issue for people who have an iodine deficiency or eat large amounts of goitrogens. Also, cooking foods with goitrogens may inactivate these compounds.

One exception to the above foods is pearl millet. Some studies have found that pearl millet might interfere with thyroid function, even if you don’t have an iodine deficiency.


What foods to avoid?
Fortunately, you don’t have to avoid many foods if you have hypothyroidism. However, foods that contain goitrogens should be eaten in moderation and ideally cooked. You may want to avoid eating highly processed foods, as they usually contain a lot of calories. This can be a problem if you have hypothyroidism, as you may gain weight easily.

Here is a list of foods and supplements you may want to avoid:
Millet: all varieties
Highly processed foods: hot dogs, cakes, cookies, etc.
Supplements: Adequate intakes of selenium and iodine are essential for thyroid health, but getting too much of either may cause harm. Only supplement with selenium and iodine if a healthcare professional has instructed you to do so.


The bottom line
Hypothyroidism, or an underactive thyroid, is a health condition that affects 1–2% of people worldwide.
It can cause symptoms like tiredness, weight gain, and feeling cold, among many others.
Fortunately, eating the right nutrients and taking medications may help reduce your symptoms and improve your thyroid function.

Nutrients that are great for your thyroid are iodine, selenium, and zinc. Following a thyroid-friendly diet can minimize your symptoms and help you manage your weight. It encourages eating whole, unprocessed foods and lean protein.