Inside: Zinc is an important supplement for thyroid health. Different forms of Zinc exist, so here we discuss which is best form and the right dosage of Zinc for thyroid health.
Thyroid disorder is one of the most common autoimmune diseases at this point in the country. It affects mainly females and the incidence is rising rapidly.
Most of the time the only treatment available for hypothyroidism is taking thyroid medicines which people are told are for life long basis. There is rarely a discussion about the root cause of why they developed a thyroid disorder in the first place.
Also, there is a lack of knowledge about is there anything besides the thyroid medicine that people can do to support their thyroid. It is often seen that people even being on the thyroid medicines don’t feel the best, and sometimes using supplements can be helpful in improving Thyroid Symptoms.
Why do you need Zinc to Improve your Thyroid Health
One of the supplements that support thyroid health is Zinc.
Zinc is such an important mineral and can help improve immune function, and also important for skin, eyes, and heart health. It is also important in thyroid health.
Zinc is important for thyroid hormone synthesis as it regulates the deiodinases enzymes.
These enzymes are responsible for producing thyroid hormones in your body. Zinc also has a role in the functioning of our master endocrine gland the Pituitary and Hypothalamus, and it can affect the release of thyrotropin-releasing hormone (TRH) and thyroid-stimulating hormone (TSH) synthesis.
Zinc also plays an important role in the conversion of T4 hormone to T3 hormone. Why that is important is because T3 is the active form of thyroid hormone and several people who have zinc deficiency cant convert T4 to T3 so the levothyroxine which is mainly T4 doesn’t help with their symptoms.
Studies have shown that zinc deficiency has been correlated with low T3 levels in patients, and supplementation with zinc has shown to improve the T3 levels.
One study showed that Zinc when used alone or in conjunction with selenium has shown to lower the TSH levels and increase the T3 and T4 levels.
What are the food sources of Zinc
Our body has no specialized system for storing zinc, so daily intake and absorption is essential.
Zinc from animal sources is absorbed better as compared to the plant sources. Phytates—elements found in plant-based, high-fiber foods—can bind minerals and inhibit zinc absorption.
Other minerals, including iron, calcium, and copper, can interfere with zinc absorption, further affecting zinc levels.
So that’s the reason because of poor bioavailability and also interference in the absorption of zinc from dietary and other minerals it might be a wise idea to have zinc supplement.
Following are some sources of zinc from the food —
Animal Sources for Zinc
- Shellfish: Oysters
- Beef liver
- Lobster, and
Plant Sources for Zinc
- Legumes: Chickpeas, lentils, beans.
- Nuts and seeds
- Whole grains
- Certain vegetables: Mushrooms, Kale, Peas, Asparagus and Beet greens
What is the Best Form of Zinc Supplements for Thyroid?
Various forms of zinc supplements are available in the market but not all of them are created equal. It’s very confusing for a lot of my patients to figure out which one is the best zinc supplement for them.
The various forms of zinc available are:
- Zinc sulfate
- Zinc gluconate
- Zinc orotate
- Zinc citrate
- Zinc glycinate
- Zinc picolinate
The big question is why do these different forms exist and is there a difference between these forms.
Now as we saw above that the dietary zinc might not be absorbed readily in to our body, so to enhance the absorption they are combined with other compounds to increase the absorption.
Over the course of years, different compounds have been identified and used. So that’s the reason different forms have been developed and they have different properties in terms of how much they can be absorbed and what side effects they can have.
The most current concept in zinc supplements is to use chelated zinc and combine it with amino acids which increases their absorption rate significantly. These are the zinc picolinate and zinc glycinate.
A study was done to compare the absorption of zinc picolinate, zinc citrate and zinc gluconate, which showed that the picolinate group levels of zinc was much higher than the others.
Another study was done this time to compare the bioavailability of zinc glycinate as compared to gluconate. The results showed that the levels were higher for zinc glycinate in this study.
So, as per these studies, it looks like the zinc picolinate and zinc glycinate both look like good options, but is there a better one.
There was another small study done on 14 patients to compare the zinc glycinate, zinc picolinate, and other forms of zinc.
And the results showed that zinc glycinate performed the best for increasing the acute uptake of zinc in the body. Although since this study was very small the results should be evaluated with caution.
But another study that favours glycinate is the one which compared the bioavailability of Zinc glycinate with sulfate but this time in the presence of diet high in phytates. The results showed that the glycinate had more bioavailability because glycinate absorption is not affected by phytates.
So it looks that the bioavailability of both Picolinate and glycinate is good. But the glycinate has another advantage that its absorption is not affected by dietary phytates and from minerals in the diets or from other supplements.
So I do like Zinc glycinate better than picolinate. But I think both are good ways of supplementing zinc.
Caution With Dosage of Zinc.
The dosage of zinc intake is important because you don’t want to take more than 30mg per day of zinc. Reason being that high zinc can lower your body levels of copper and which can have detrimental effects.
There are only certain circumstances when a higher dosage of zinc are used, but that should be done with the help of your medical practitioner.
So if you have thyroid problems than zinc supplementation should be part of your care. Especially as Zinc is involved in producing thyroid hormones and more importantly is important for converting T4 to T3 hormone.
Zinc deficiency can be the reason your thyroid is not working optimally, and thus your symptoms might not be better even after taking the medicine especially levothyroxine which is, mainly T4. Do get your zinc levels checked before taking the supplement and try to get Zinc glycinate form of zinc and do not take more than 30 mg of zinc supplement.
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Research References for Zinc supplement for Thyroid:
Mahmoodianfard S1, Vafa M2 Effects of Zinc and Selenium Supplementation on Thyroid Function in Overweight and Obese Hypothyroid Female Patients: A Randomized Double-Blind Controlled Trial.J Am Coll Nutr. 2015;34(5):391-9. doi: 10.1080/07315724.2014.926161. Epub 2015 Mar 11.
Gandia P1, Bour D, A bioavailability study comparing two oral formulations containing zinc (Zn bis-glycinate vs. Zn gluconate) after a single administration to twelve healthy female volunteers.Int J Vitam Nutr Res. 2007 Jul;77(4):243-8.
Robert A DiSilvestro and Melinda Swan. Comparison of Four Commercially Available Zinc Supplements for Performance in a Zinc Tolerance Test. https://www.fasebj.org/doi/abs/10.1096/fasebj.22.1_supplement.693.3
Schlegel P1, Windisch W. Bioavailability of zinc glycinate in comparison with zinc sulphate in the presence of dietary phytate in an animal model with Zn labelled rats.J Anim Physiol Anim Nutr (Berl). 2006 Jun;90(5-6):216-22.