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6 Every Day Things You’re Doing That’s Affecting Your Thyroid (Number 3 will Surprise You)

Updated: May 26, 2023

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You noticed that you were feeling tired all the time, unable to lose weight or exercise. You weren't sleeping well even though you felt absolutely fatigued. You finally decided to go to the doctor and get an answer to what's been happening to you.

Hypothyroidism also called low thyroid function.

Did you know that there are things that you are doing daily that's affecting your thyroid and contributing to low thyroid function?

Check out this list to see how your daily activities are contributing to lowered thyroid function.

Things that are Affecting Your Thyroid

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1. Chronic Stress

Everyone knows that long-term stress isn't good for you but very few know why. Stress works in a number of different ways to wreak havoc on your body including exacerbating or contributing too low thyroid function. How? Well there's something called the HPA (hypothalamic-pituitary-adrenal) axis.

This basically means that there is a strong network and feedback system connecting your brain and your body, specifically your hypothalamus, a region of your brain that controls your autonomic nervous system, your pituitary, the "master" gland attached to the base of your brain that controls other hormone glands in your body (like your adrenals), and your adrenal glands which secrete hormones like epinephrine (adrenaline) and cortisol.

When you are under a huge amount of stress, your HPA axis is activated and cortisol, a multifunctional stress hormone, is released into your body. Now cortisol isn't all bad, you need this hormone for a lot of different actions in the body like reducing inflammation and acting on blood sugar levels, but too much cortisol is like a calling card for low thyroid function.


Because too much cortisol, which is normally anti-inflammatory, is related to an increase in inflammation in the body through inflammation causing molecules called inflammatory cytokines [1]. Increased inflammation and oxidative stress go hand in hand. Both are linked to decreased conversion of T4 to T3 [2].

T3 is the biologically active form of thyroid hormone while T4 is the more widely available storage form.

Research shows that cortisol is also related to an elevation in TSH [3]. TSH, thyroid stimulating hormone, is secreted by the pituitary gland when thyroid hormones T3 and T4 are low. TSH's job is to, well, stimulate the thyroid to produce more T4 and by extension, the powerful T3.

Higher TSH means that the body isn't producing enough thyroid hormone (T4 and T3) to function properly.

So what does all of this mean?

It means that by decreasing stress and regulating cortisol, you can reduce your chances of harming your thyroid.

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2. Eating Gluten

In the past few years, gluten has become a sort of villain in many fields of medicine (other than conventional medicine, e.g. your run-of-the-mill MD). That's because gluten has been linked to all kinds of disorders from fibromyalgia [4] to schizophrenia [5].

But did you know that gluten is also linked to thyroid dysfunction, specifically autoimmune or Hashimoto's thyroiditis [6]?

The way that gluten affects the thyroid is a bit nuanced. Although low thyroid function has a few different causes from congenital (at birth) to iatrogenic (caused by medications, which we'll get to later), a big portion of those suffering from thyroid dysfunction is due to autoimmune thyroiditis.

Autoimmune thyroiditis (or Hashimoto's thyroiditis, named for the physician who discovered it), is linked to gluten through a "leaky gut" mechanism.

The cells of your intestines are supposed to be situated tightly together to prevent foreign particles from entering into your blood stream. In an ideal situation, this would be the case for the majority of time.

Those with leaky gut, have intestinal cells that aren't as tight together as they should be so foreign particles are allowed into the bloodstream at a higher rate. Since the body doesn't recognize this particles (possibly from ingested food, proteins from bacteria and viruses, even your own body’s cells), your body starts to mount an attack against it.

This attack can and usually does become full blown autoimmune disease as the body starts to attack itself.

But that does this have to do with gluten?

Gluten is composed of two proteins: glutenin and gliadin.

Gliadin has been shown to increase the production of an endogenous (or self made) protein called zonulin [7]. Zonulin increases the spaces between your intestinal cells allowing more foreign particles into the blood stream.

Essentially feeding the fires for autoimmune disease which includes autoimmune thyroiditis.

Avoiding gluten has been shown to be positive for many conditions including autoimmune thyroiditis [8, 9].

Avoiding gluten might be hard at first but choosing lots of fresh vegetables, fruit, and lean proteins can help curb any gluten/carb cravings.

glasses of water with ice

3. Brushing Your Teeth and Drinking Tap Water

Yes, brushing your teeth and drinking tap water can negatively affect your health, specifically your thyroid.

I'm not advocating putting down your toothbrush and toothpaste or swearing off water forever but if you are using toothpaste with fluoride or drinking the water that comes out of your faucet unfiltered, there's a good chance that your thyroid is being affected.

Why? Fluoride.

Fluoride, in it’s natural form of calcium fluoride, is a naturally occurring mineral and is found in some sources of natural water.

This natural form of fluoride is much different than the the sodiumfluoride or sodiummonofluorophosphate found in toothpastes. Or the fluorosilicic acid added to the public U.S. water supply.

While there is considerable evidence that fluoride isn't as helpful or harmless as it seems (most European countries don't even fluoridate their water and neither does Japan) and fluoride has been classified as a neurotoxin, many in conventional medicine still question the effects of fluoride on the thyroid gland.

Research has shown that fluoride can affect thyroid levels even at less than 0.5mg/L[10]. Your average toothpaste most likely has 0.76 of sodiummonoflurophosphate with 0.15% fluoride ion. This means that if you are brushing your teeth 2-3 times a day you're possibly exposing your thyroid to between 0.30- 0.45% of the neurotoxic and thyrotoxic fluoride.

It's gets even worse if you drink tap water that hasn't been filtered for fluoride. Most cities in the U.S. fluoridate their water at 0.70mg/L which is definitely higher than 0.5mg/L.

Long-term low dose fluoride exposure has not only been linked with altered thyroid hormones but also to damage and degeneration of the thyroid itself [11].

If if you find yourself swallowing even a small amount your toothpaste after brushing or rinsing your mouth with tap water, this could be negatively affecting your thyroid.

Although fluoride levels in U.S. public drinking water is said to be "safe", (you can check you municipalities fluoride level in the water here), if you are suffering from thyroid dysfunction consider switching to a non-fluoridated tooth paste and avoiding tap water completely to lower your overall thyroid burden to the thyrotoxic fluoride.

woman standing in the sun with a sun hat on

4. Having Low Vitamin D Levels

Low vitamin D levels (whether deficiency or insufficiency), are a global health problem. Many don't realize that vitamin D is more of a steroid hormone than a vitamin and that it plays a central role in many bodily functions, including our immune system regulation.

Low vitamin D levels are not only associated with thyroid dysfunction [12], but increasing vitamin D levels were shown to improve thyroid function [13, 14]. Studies show that 50,000 IU of vitamin D, weekly for 12 weeks, was enough to significantly improve the function of the thyroid.

While getting vitamin D from the sun is ideal (our bodies make vitamin D), it's usually not enough, even more so for darker skinned people. Taking supplements may be a good option for increasing your vitamin D levels, but caution should be exercised when increasing vitamin D through supplementation due to vitamin D toxicity.

I always recommend getting tested to see your vitamin D levels first, and then talking with your naturopathic doctor before starting a vitamin D supplement regimen.

a small cosmetic pot filled with pink powder with a brush laid on top of it

5. Wearing Sunscreen and other Cosmetics

Speaking of not getting too much sun, are you wearing sunscreen?

While sunscreens are a great ideal to avoid skin damage and potentially skin cancer, the type of sunscreen you're using could be contributing to thyroid dysfunction.

This is because certain sunscreens and certain cosmetics like lip balm, foundations, and nail polish, contain a chemical called benzophenone and it's related molecules.

Benzophenone is a white organic compound with a flower-like smell.

Benzophenone, when added to products like lip balms and shampoos, prevents degradation from UV light exposure. Hence it's chemical relative (oxybenzone and avobenzone) appearing in many sunscreens.

Benzophenone has been shown to not only be absorbed into the blood screen thorough the skin but to also contribute to low T4 levels, high TSH levels, and altered anti-TPO levels [14].

Avoiding this chemical could be crucial to improving thyroid health. Should you skip the sunscreen altogether? Not necessarily. If you are outside for more than the amount of time to get adequate vitamin D (this varies for different people), then consider using safer sunscreens that use physical UV blockers like titanium dioxide or non-nano sized zinc oxide.

a bottle of prescription medication tipped over with the medicine spilled onto a gray tabletop

6. Your Prescription Medication

Remember when I touched on iatrogenic (drug-induced) thyroid dysfunction?

Some medications have thyroid dysfunction as an adverse effect.

That's because some medications like Prozac®, Diflucan®, Prevacid®,and fluoroquinolone antibiotics contain fluoride which was discussed above. For a more comprehensive list, visit the Fluoride Toxicity Research Collaborative.

Other medications, like Interferon, a drug used for tumors and hepatitis C, directly attacks the thyroid gland or causes your body to attack the thyroid gland . And Lithium, a drug used for mental illnesses, causes your body to produce antibodies against the thyroid, leading to low thyroid function [14].

Amiodarone causes hypothyroidism due to its high amount of iodine and it’s ability to inhibit T4 and T3 secretion as well as thyroid inflammation. While corticosteroids cause hypothyroidism but suppressing TSH [15].

While it's not advised to stop taking your prescription medication, talk to you primary care provider or your naturopathic doctor to see if there are safer options for your thyroid.

If you've been having low thyroid function, contact your naturopathic physician today to see how you can start on the path to a healthy life!


Woman in watermelon dress holding a piece of watermelon
I'm Dr. Candace Mathers, a naturopathic physician,helping you repair, restore, and renew your health and life to new heights! I'm a Christian, a mother, and lover of the outdoors.

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