High cholesterol is a risk factor for heart disease and stroke. High cholesterol levels can stem from your diet, especially if you eat foods high in saturated fats, like red meat and butter. Sometimes, though, your thyroid gland may be to blame. Too much or too little thyroid hormone can make your cholesterol levels swing up or down. Here’s a look at how your thyroid affects cholesterol.
The thyroid gland
The thyroid is a gland located in the neck. It produces two hormones, known as the thyroid hormones. The main ones are triiodothyronine (T3), which is the active form of thyroid hormone, and thyroxine (T4), which the body converts to T3.Thyroid hormones play a role in regulating: brain development in children، body temperature،metabolism and the function of the heart, brain, muscle, and other organs.The pituitary gland secretes thyroid-stimulating hormone (TSH) to stimulate the thyroid to produce hormones.
Cholesterol
A cholesterol buildup in the arteries can cause heart disease. Cholesterol is a waxy substance that is present in every cell in the body. The body uses cholesterol to make hormones as well as bile acids to help digest fat. When too much cholesterol builds up in the arteries, it can cause problems, such as heart disease. Cholesterol travels through the blood by attaching itself to a protein. This bundle of cholesterol and protein is called a lipoprotein. The main lipoprotein bundles are:
High-density lipoprotein (HDL): HDL is so-called because there is a high cholesterol to protein ratio. It is also known as “good” cholesterol because it helps the body get rid of cholesterol from the blood.
Low-density lipoprotein (LDL): LDL features a low cholesterol to protein ratio. It is also known as “bad” cholesterol. Higher LDL rates indicate a higher risk of heart disease.
Although dietary causes (in those predisposed to it) may cause a buildup of bad cholesterol in the blood, it may also arise from some medical conditions, including thyroid disorders.
Understanding the link between the thyroid and cholesterol
The link between the thyroid and cholesterol can result in conditions affecting each of them:
underactive thyroid cause high cholesterol: Thyroid hormones, especially T3, play an essential role in helping the liver process and remove any excess cholesterol from the body. When the body does not produce enough thyroid hormones, the liver cannot process as much cholesterol as it should. An underactive thyroid means that the body removes less “bad” cholesterol from the blood than it should, which often leads to high levels of “bad” and total cholesterol. The research also suggests that a person’s cholesterol levels may improve once they have received treatment for an underactive thyroid, even if they do not require cholesterol-lowering medications. Even mildly low thyroid hormone levels (subclinical hypothyroidism) can lead to high cholesterol. According to 2012 research, elevated TSH levels can also cause high cholesterol, even if T3 and T4 are not elevated.
overactive thyroid cause low cholesterol: An overactive thyroid might have the opposite effect and cause low levels of cholesterol in the blood. However, there is no scientific proof that low cholesterol increases the risk for health problems. People with an overactive thyroid can get relief from their symptoms by taking medications to reduce thyroid hormone production. Lower levels of the hormone may also increase their cholesterol levels if they are low. If medications do not work, the doctor may suggest radioactive iodine to shrink the thyroid gland or surgery to remove part of the gland, which will reduce hormone levels. People who have low cholesterol caused by high thyroid hormone levels may see their cholesterol levels increase as a result of the treatment.
Reference
https://www.medicalnewstoday.com/articles/322618.php#takeaway
https://www.healthline.com/health/thyroid-issues-and-cholesterol#tests-and-treatments
https://www.thyroid.org/patient-thyroid-information/ct-for-patients/vol-5-issue-12/p-3/
