If you’ve been struggling to lose weight or are gaining weight unexpectedly… if you lack energy, experience poor mood, or have difficulty focusing… or if you have a hard time sleeping, it’s possible your thyroid may not be running at full throttle.

While small, the thyroid is not a gland to be taken lightly. As your body’s “master controller,” your thyroid is responsible for regulating nearly every major metabolic function in your body: from the metabolic rate (the rate your body uses energy and burns calories) to the building of new proteins to sensitivity to other hormones, and much more. In fact, every cell in the body has receptors for thyroid hormone!

So it shouldn’t come as a surprise to learn that if your thyroid’s not operating at its full potential, it can negatively impact nearly every aspect of health. In addition to those mentioned above, here are a few more telltale signs to watch for.^1,2 (Maybe you can even relate to some of them?)

• Poor digestion
• Muscle and joint discomfort
• Feeling cold
• Dry hair and skin
• And more

The good news is there are several key nutrients essential in supporting optimal thyroid health and function. Even better, all these nutrients are ones you can easily find in common foods.

Foods to Optimize your Thyroid Health

Iodine

Iodine is arguably the most well-known thyroid nutrient, as it’s one of two basic building blocks (the other being the amino acid tyrosine) of thyroid hormone. Simply put, if you don’t have enough, thyroid function will be compromised.

Fortunately, you don’t have to rely on fortified foods like iodized salt to support optimal levels of iodine. Some of the best dietary sources of iodine include:

• Sea vegetables (e.g., kelp, nori, kombu, wakame)
• Scallops
• Yogurt
• Shrimp
• Sardines
• Salmon
• Eggs

Having said that, care must be taken with iodine consumption. Too much iodine can decrease the activity of an enzyme called thyroid peroxidase (TPO), which plays an essential role in thyroid function.³ Interestingly, excess iodine seems to cause problems only when it’s accompanied by too little…

Selenium

Selenium is more highly concentrated in the thyroid gland than in any other organ. This mineral is necessary for the conversion of the inactive form of thyroid hormone (T4) to the metabolically active form (T3). Research has shown that folks with lower intakes of selenium have lower levels of T3.⁴

Brazil nuts are a particularly rich source of selenium, and research has shown they are more effective than supplements at raising blood levels of selenium.5 [Note: It’s important to not go “nuts” on Brazil nuts, as too much selenium can be toxic. Two to three Brazil nuts per day is a good starting point.]

In addition to Brazil nuts, the following are excellent sources of selenium:

• Tuna
• Shrimp
• Sardines
• Salmon
• Turkey
• Chicken
• Lamb
• Scallops
• Beef

Zinc

Zinc also plays an important role in the conversion of T4 to T3. Just like selenium, deficiencies in zinc can slow the body’s conversion rate. In fact, research has shown that zinc deficiency can decrease activity of the enzymes that convert T4 to T3 by as much as 67%.⁶ That could mean running on only one-third of your thyroid potential!

The following foods are excellent sources of zinc:

• Beef
• Lamb
• Sesame seeds
• Pumpkin seeds
• Lentils
• Garbanzo beans
• Cashews

Copper

Inadequate levels of copper have been linked to low concentrations of T3.⁸ In one study published in The Journal of Nutrition and Biochemistry, researchers found that copper deficiency in rats resulted in reduced T3, lower body temperatures, and elevated TSH, which suggests copper deficiency interferes with thyroid hormone metabolism.⁹

Some of the best dietary sources of copper include:

• Sesame seeds
• Sunflower seeds
• Cashews
• Mushrooms
• Spinach and other dark, leafy greens
• Asparagus

Iron

Iron also plays a key role in thyroid function, and like copper, inadequate levels of iron have been linked to low levels of T3.¹⁰ Deficiencies in iron impair the body’s ability to make thyroid hormone by reducing the activity of TPO. (Remember, that’s one of the enzymes required for optimal thyroid production.)¹¹

While many foods contain iron, where you get it matters. For instance, non-heme iron from plant-based foods (e.g., spinach, lentils, beans, sesame seeds) is not well absorbed. On the other hand, heme iron, which is found in beef and other animal-based foods, is much more readily absorbed. Interestingly, combining sources of heme iron with non-heme iron (i.e., beef plus veggies) increases the amount of non-heme iron absorbed.¹² This is often referred to as the “meat factor” of iron absorption.

In addition, vitamin C, which may promote healthy thyroid function in its own right, facilitates the absorption of non-heme iron when the two are combined.^13,14 Dark, leafy greens commonly provide a healthy combo of iron plus vitamin C.

Omega-3 Fats

Omega-3 fatty acids (e.g., EPA and DHA) help support optimal thyroid function both directly and indirectly. On one hand, they enhance the action of thyroid hormone signaling. On the other, they help promote a healthy inflammatory response and enhance immune system function.^20,21

The best sources of omega-3 fatty acids are microalgae and cold-water fish, shellfish, and mollusks such as:

• Herring
• Sardines
• Oysters
• Salmon

The best plant-based sources of omega-3 fats are flaxseeds, walnuts, and chia seeds. It’s important to note, however, that these foods contain a form of omega-3 (ALA) that’s easily burned off, not readily converted to the more important DHA and EPA, and as a result, doesn’t carry the same potential health benefits.²²

More Benefits of Omega-3

Vitamin A

 Vitamin A has been shown to regulate thyroid hormone metabolism and promote healthy levels of thyroid-stimulating hormone (TSH), which signals the production of thyroid hormones. However, more TSH is not necessarily better. In fact, when TSH is produced in excess, it can be a sign that the thyroid gland is not working optimally.

In a study published in The Journal of the American College of Nutrition, researchers from Iran found that supplementation with vitamin A for four months normalized TSH levels and significantly increased T3 in healthy women.¹⁵

You don’t have to rely on supplements to get your vitamin A, which also helps T3 communicate with your cells. Here are several foods that can help keep your master controller humming along:

• Sweet potatoes
• Carrots
• Spinach, kale, and other dark, leafy greens
• Winter squash
• Bok choy
• Cantaloupe
• Bell peppers
• Broccoli

Vitamin B12

Research has shown a strong link between B12 deficiency and suboptimal thyroid function. In one study, researchers found that 58% of B12-deficient participants given B12 shots monthly experienced significant improvements in some of the telltale signs associated with suboptimal thyroid function.¹⁶ Some of the best dietary sources of B12 are:

• Sardines
• Salmon
• Tuna
• Lamb
• Scallops
• Shrimp
• Beef
• Yogurt
• Eggs

Get Your Motor Runnin’

If you’ve been struggling with some of the telltale signs of suboptimal thyroid, including weight gain or difficulty with weight loss, the good news is that regularly consuming these thyroid-nourishing nutrients combined with an overall healthy diet and lifestyle may help you “get your motor runnin’,” as the Steppenwolf lyrics go.