How Does Thyroid Gland Affect Cholesterol?
Your doctor may have warned you about cholesterol, a fatty, waxy substance that circulates in the blood. Too much bad cholesterol can clog your arteries and put you at risk for heart disease.
High cholesterol can come from your diet, especially if you eat foods high in saturated fats, such as red meat and butter. Sometimes, however, it can be caused by your thyroid. Too much or too little thyroid hormone can cause your cholesterol levels to rise or fall.
Here’s how your thyroid gland can affect your cholesterol.
What is the thyroid gland?
The thyroid is a butterfly-shaped gland located in the neck. It produces hormones that control your metabolism. Metabolism is the process by which your body converts food and oxygen into energy. Thyroid hormones also help the heart, brain and other organs to function properly.
The pituitary gland, located at the base of the brain, directs the activity of the thyroid gland. When the pituitary gland senses that thyroid hormone levels are low, it releases thyroid-stimulating hormone (TSH); TSH tells the thyroid to release more hormone.
The power of the thyroid gland
The thyroid gland can be thought of as the body’s master regulator. Thyroid hormones regulate metabolism by stimulating the mobilization and breakdown of lipids such as cholesterol and help the liver synthesize fatty acids, among other functions.
Therefore, hypothyroidism (underactive thyroid) and hyperthyroidism (overactive thyroid) can have a unique impact on your cholesterol profile. For some people, managing these effects may be the key to managing dyslipidemia.
Cholesterol is found in every cell in your body. Your body uses it to make hormones and substances that help you digest food.
Cholesterol also circulates in the blood. It circulates in the blood in two forms, called lipoproteins.
- High-density lipoprotein (HDL) cholesterol is good for your heart. It removes cholesterol from the body and protects against heart disease.
- Low-density lipoprotein (LDL) cholesterol is bad for the heart. When LDL cholesterol levels are too high, it can clog arteries and lead to heart disease, heart attacks, and strokes.
Underactive or overactive thyroid
The thyroid gland may produce too much or too little of a hormone.
Hypothyroidism is a condition in which the thyroid gland does not function enough. When your thyroid is not active, your whole body feels sluggish. You may feel tired, lethargic, cold, and sluggish.
You may have hypothyroidism if you have any of the following conditions
- Hashimoto’s thyroiditis is an autoimmune disease in which the body attacks the thyroid gland and destroys…
- Inflammation of the thyroid gland (thyroiditis)
Other causes of hypothyroidism include…
- Thyroidectomy (removal of the thyroid gland)
- Over-radiation of the thyroid gland
- There are also drugs such as lithium, interferon alpha, and interleukin-2
- Pituitary gland damage
Hyperthyroidism is a condition in which the thyroid gland is overactive. When the thyroid gland is overactive, the body goes into high gear. Your heart rate increases and you become tense and restless.
If you have an overactive thyroid, you may have an overactive thyroid.
- Graves’ disease
- Herbal nodular thyroiditis
How does the thyroid gland cause cholesterol problems?
The body needs thyroid hormones to make cholesterol and to excrete unwanted cholesterol. When thyroid hormone levels are low (hypothyroidism), the body cannot break down or remove LDL cholesterol as it normally would. This can lead to a buildup of LDL cholesterol in the blood.
You don’t have to have very low thyroid hormone levels to raise your cholesterol. Even people with slightly lower thyroid levels, called subclinical hypothyroidism, can have higher than normal LDL cholesterol levels, and a 2012 study found that high TSH levels directly raise cholesterol levels even when thyroid hormone levels are not low.
Hyperthyroidism has the opposite effect on cholesterol. It causes abnormally low cholesterol.
What are the symptoms?
If you notice any of these symptoms, your thyroid may be underactive.
- Weight gain
- Slow heartbeat
- Muscle pain and weakness
- Dehydrated skin
- Inability to remember
An overactive thyroid has almost opposite symptoms.
- weight loss
- Sensitivity to heat
- appetite for food
- Sleep disorders
Effectiveness of hypothyroidism treatment
A large study published in JAMA Internal Medicine in 2014 found that 60% of patients with newly diagnosed hypothyroidism and hyperlipidemia had lower high cholesterol levels after recovery of thyroid function. Among patients treated with levothyroxine, 75% did not require lipid-lowering medication for one year after treatment for hypothyroidism. This percentage may be higher given that not all study participants had their cholesterol levels checked after recovery of thyroid function.
Based on the effect of thyroid replacement on blood lipids, it can be inferred that hypothyroidism treatment has the potential to reduce the risk of heart disease. There is further evidence that this is true, as levothyroxine has been shown to have a positive effect on carotid artery intima-media thickness (an indirect measure of heart disease risk).
As a result of this evidence, professional societies such as the American Association of Clinical Endocrinologists make recommendations to all physicians caring for patients with dyslipidemia.
In some cases, if cholesterol levels remain elevated after treatment and lifestyle measures, such as diet, weight loss, and exercise, have not worked, consider taking cholesterol-lowering medications.
Get your thyroid and cholesterol checked
If you have thyroid symptoms and your cholesterol is high or low, see your doctor. You will have blood tests to measure your TSH levels and your thyroid hormone levels, called thyroxine. These tests can help your doctor determine if your thyroid is overactive or underactive.
Levothyroxine is a thyroid hormone replacement drug that is also used to lower cholesterol levels to treat a weak thyroid.
If your thyroid hormone levels are only slightly elevated, you may not need a thyroid hormone replacement. Your doctor may prescribe a statin or other medication to help lower your cholesterol.
If you have hyperthyroidism, your doctor may prescribe medications to shrink your thyroid gland with radioactive iodine or to suppress thyroid hormone production. Some people who cannot take thyroid medications may need surgery to remove most of the thyroid gland.