Zinc and Thyroid Health

Did you know that zinc is crucial for thyroid health? We don’t tend to think about mineral deficiencies when we think about thyroid functioning, and when we do iodine or selenium are usually mentioned, but zinc is just as important.

Let’s have a look about zinc and thyroid health;

- Zinc is required to be able to convert the thyroid hormone T4 into T3, and T3 being the active thyroid hormone, optimal zinc levels or zinc supplementation can help with thyroid hormone metabolism. Studies have shown that zinc supplementation improves thyroid hormone production and that zinc, in the case of Hashimoto’s, can help reduce thyroid antibodies.

- The thyroid hormone receptors in the hypothalamus also require zinc in order to assess if our thyroid hormone levels are sufficient or not. Low zinc levels therefore can cause the body to reduce the thyroid hormone secretion if it thinks zinc levels are sufficient.

- Zinc deficiency is also considered a potential cause that might lead to hypothyroidism.

If we look at the wider picture, and consider the thyroid as part of the endocrine system and directly connected with and influenced by the adrenal glands, then whatever stresses the adrenal glands will eventually play a role in thyroid health. One of the most common health imbalances is unstable blood sugar levels that impact adrenal function, stress up the pituitary gland and end up causing hypothyroidism or flaring up Hashimoto’s. Zinc deficiency has been correlated with a higher risk for insulin resistance, and supplementation has been proven to be important in supporting insulin resistance as zinc acts on insulin receptors to make cells more sensitive to this hormone and improves thus insulin sensitivity. 

Where do we find zinc in our food? The foods with the highest amount of zinc are liver (especially calf liver), oysters and wheat germ. A decent amount of zinc we can also find in beef products, lamb, veal, offal, other crustaceans, some types of cheese, beans and other legumes (lentils, peas), pumpkin seeds, sesame seeds and sunflower seeds, cashews, pine nuts, pecans, rye, oats or nutritional yeast. Vegetables like mushrooms, avocadoes, berries, asparagus, zucchini, peppers, garlic, leeks, spinach, and onions also have a fair amount.

So how can one become deficient in zinc? A diet rich in whole grains, nuts, seeds and legumes is also a diet rich in a natural compound called phytate that’s present in these foods. Phytate binds to minerals like zinc and impedes zinc absorption leading to zinc deficiency. We can reduce the phytate content by soaking them overnight, fermenting them or sprouting them, but it’s always wise to consume zinc rich foods away from phytate rich foods or to consider supplementation. 

Since the richest foods in zinc are animal foods, people consuming a vegan or vegetarian diet have to be especially aware of the zinc requirements, as a vegetarian diet is also a diet rich in legumes, grains and all the other phytate rich foods, and should consider supplementing at the first sign of zinc deficiency. On the other hand, a diet rich in fat like the keto diet can also displace zinc, as it’s usually found in the leaner parts of meat, so if you consume a high fat diet, eat more red meat and oysters to cover the zinc requirements.

And last but not least, a diet rich in sugar, especially refined sugar, is also a diet low in zinc. If using sugar, although the advice would be to use it sparingly, try to use better alternatives like molasses, maple syrup or maple sugar, which have a higher zinc concentration.