The impact of zinc on thyroid metabolism
The thyroid is a complex organ with vast implications for the rest of the body. It helps to regulate cellular energy and, in turn, plays a heavy role in managing weight, body temperature, blood sugar levels, cognitive function and even digestion. Unfortunately, the thyroid is also very finicky and there are many factors that could potentially kick it out of balance, so everyone's always looking for that silver bullet to keep it running optimally. Could the powerhouse mineral zinc be the cure?
Here we will answer some of the most common questions regarding zinc and thyroid health.
First of all, is zinc good for the thyroid?
Yes. The concept that zinc could play a role in optimal thyroid function was explored even back in the 1970’s. Today, we have now seen that low zinc status may contribute to a significant decrease in resting metabolic rate and free T4 levels (a thyroid hormone). One trial found that giving supplemental zinc to subjects with poor zinc status led to increased resting metabolic rate, increased free T4 and lower thyroid stimulating hormone (TSH; a marker that is conversely related to thyroid function, meaning lower amounts leads to great thyroid activity).
There are many other examples where zinc status appears to affect the function of the thyroid, but one stands out as particularly interesting: people that suffer from severe alopecia (hair loss) may actually be suffering from zinc deficiency. One case study found that simply giving thyroid hormone to a person with alopecia and documented hypothyroidism (low thyroid function) did not resolve the hair loss unless zinc was supplemented.
How does zinc help the thyroid?
Zinc, along with other trace elements such as copper and selenium, is an essential nutrient for optimal thyroid health. Specifically, it is required as a cofactor for thyroid hormone synthesis. On top of this, zinc is necessary for improving thyroid receptor sensitivity in the body tissues. In other words, even with enough thyroid hormone circulating in the bloodstream and ready to deliver the message, if there is not enough zinc in the body then that message may never meet its target tissue and increase cellular function. Zinc helps to “unlock the door” at the level of the cell so that thyroid hormones can swiftly enter.
Ironically and importantly, low thyroid function can actually lead to decreased zinc absorption. This means that a vicious cycle may be created in which the body needs more zinc to support a healthy thyroid but the body isn’t absorbing adequate amounts from food to boost thyroid levels and receptor sensitivity. This predicament suggests that multiple approaches may be necessary to properly restore zinc and thyroid status (ie. dietary changes, supplemental zinc, thyroid medications, etc).
How much zinc should I take for thyroid health?
One case report examined the intake of 26.4mg/day of elemental zinc (in the form of zinc gluconate) in females with low thyroid levels and found beneficial effects on lab markers and hypothyroid symptoms. Another trial used 30mg/day of elemental zinc (also in the form of zinc gluconate) in obese hypothyroid women with positive effects on thyroid lab markers.
Does this mean that 26.4mg/day is the precise amount to supplement in order to optimize thyroid function? Absolutely not. Various dosages have not been compared in large clinical trials to determine the ideal daily amounts for optimal thyroid health. It is recommended that you speak with a healthcare provider to determine the best amount for your thyroid function, based on your dietary intake and baseline thyroid status. As mentioned elsewhere on zinc.ca, the RDA (recommended dietary allowance) for zinc is only 8mg/day for adult females and 11mg/day for adult males in Canada.
Can you take zinc with thyroid medication?
Yes and no. Zinc and thyroid medications can be taken on the same day but should not be taken at the same time. In general, thyroid medications should not be taken at the same time as any other medications, vitamins, minerals or natural health products. Zinc is no exception.
What vitamins should not be taken with thyroid medication?
Thyroid medications should not be taken at the same time as any other medications, vitamins, minerals or natural health products. Although this applies to all natural health products, iron and zinc are unique minerals on the topic of thyroid health and thyroid medication. This is because iron, like zinc, is extremely necessary for the optimal function of the thyroid gland but it is well known to interact with other nutrients and medications. If you have low thyroid function and also suboptimal or deficient iron levels, be sure that you take both your medication and supplement as prescribed but absolutely not at the same time of day.
Which zinc type is best for thyroid function?
The available case studies and trials that have examined zinc supplementation in low thyroid status utilized zinc gluconate. However, there are many forms of zinc such as zinc oxide, zinc citrate, zinc carnosine and zinc bisglycinate. Given that the ultimate goal is to ensure adequate zinc tissue levels, it stands to reason that zinc bisglycinate is the best choice for those with poor digestive function, sensitive stomachs or individuals that want the best possible absorption rate for minerals.
All in all, zinc appears to play an important role in the functioning of the thyroid gland. At the same time, it is only one piece of the overall puzzle. If you want optimal thyroid function, don’t neglect your zinc status but also don’t expect it to be a quick fix if other areas of your health are neglected, too.