thyroid and cholesterol connection

Patients with abnormal lipid profiles (including cholesterol) are often prescribed cholesterol-lowering medications. I often tell my patients that their thyroid health directly affects their blood-cholesterol levels. Many patients are surprised as their primary physician may not have investigated this connection.

The Claim: Your Cholesterol May be High Due to Low Thyroid Function

You’ll see there is a strongly established connection. Any patient with elevated cholesterol needs to investigate why it’s high before commencing any treatment, especially cholesterol-lowering medications.

Cholesterol and its Connection to Heart Disease

Cholesterol was once thought to be bad. Then it was determined to be good. In fact, in 2015, dietary guidelines changed and stated 'cholesterol is not a nutrient of concern'. Understanding LDL-cholesterol and HDL-Cholesterol is vital to optimizing overall heart health.

In general, LDL is associated with risk and HDL is considered protective.

The reason LDL-C is a risk factor associated with heart disease is that it tends to be more susceptible to damage than HDL-C, and happens to be in circulation longer. When we look at atherosclerotic plaques, we do see cholesterol, among other things. There are many contributing factors to the atherosclerotic plaque, not just the presence of cholesterol. This is depicted in the image below.

Picture of a normal artery versus a narrowed artery clogged with atherosclerotic plaque, which is made up of several substances, including cholesterol

Thyroid Hormones are required for LDL Metabolism

Our muscles, liver, and many other cells, have LDL-receptors on them to allow LDL to enter cells [1]. If, for some reason, LDL molecules can’t enter the cells, they will stay in the blood. In all mammals, including humans, thyroid hormone depletion leads to decreased LDL receptor expression and elevated cholesterol in the blood. This phenomenon has been known since the 1920s [2]. In fact, it’s well documented that low functioning thyroid can and will directly affect total cholesterol and LDL in the blood [2].

Treating Thyroid May Help with Cholesterol

This will only help for some people. Not everyone with high cholesterol has a low functioning thyroid; but it certainly warrants investigation.

In many studies, giving T3 and T4 (thyroid hormones) have lowered total cholesterol and LDL-cholesterol in the blood [2]. In other research, mice induced with hypothyroidism saw cholesterol levels increase over time. Then when treated for their low functioning thyroid, their cholesterol levels dropped again. [2].

If your Cholesterol is High, Check Your Thyroid

Cholesterol is quite important for life, so taking a cholesterol-lowering medication (such as a statin) can be quite dangerous if it wasn’t needed in the first place. Asking your doctor to investigate why your cholesterol is high is a fair request. Looking at a full thyroid panel would be helpful, such as TSH, T3, T4 and reverseT3. Your naturopath would be able to assist you in a full work up.


Interested in learning more?

Read on in our series of articles on Heart Health!

About the Author - Dr. Johann de Chickera

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Dr. Johann is a fully licensed Naturopathic Doctor. His approach emphasizes the importance of living a healthy lifestyle and improving one’s health naturally. Dr. Johann obtained a Doctor of Naturopathy at the Canadian College of Naturopathic Medicine (CCNM). Education at CCNM is a vigorous four years, with a curriculum involving biomedical sciences, physical diagnosis, clinical nutrition, traditional Chinese medicine and acupuncture, botanical (herbal) medicine, physical medicine, homeopathy and lifestyle management.

While Dr. Johann has a general practice, he focuses on fertility, hormonal imbalances, gut health, and autoimmune disease.

To book in please call us at (519) 442-2206 or click here.

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