What is the Link Between Thyroid Problems and Cholesterol?

High cholesterol or hypercholesterolemia is a condition in which a person has increased levels of cholesterol which puts him at increased risk for various cardiovascular diseases and stroke. Generally diet and a sedentary lifestyle is the primary reason for a person to have high cholesterol but sometimes certain medical conditions like thyroid dysfunction can also cause hypercholesterolemia. This may happen when the thyroid gland produces abnormally high or abnormally low levels of thyroid hormones. The link between high cholesterol and thyroid problems have been known to researchers now for decades. It is well-known that hypothyroidism, a condition in which the thyroid gland produces too little hormones, has a direct link with elevated levels of LDL or “bad” cholesterol. However, the studies to investigate this link have shown variable results [1, 2, 3].

In some studies, there have been no link identified while in others a strong relationship has been established between thyroid disorders and elevated levels of cholesterol. Anatomically speaking, the thyroid gland is responsible for producing hormones that are very crucial for various metabolic activities that take place in the body. The thyroid hormones play a vital role in the brain development in children. It also helps in maintaining normal body temperature. It also is vital for normal growth and development of a person. It is the thyroid hormones that allow the vital organs of the body like the heart, brain, and other muscles to function normally [1, 2, 3].

The pituitary gland in the brain produces a hormone called thyroid stimulating hormone which stimulates the thyroid gland to produce the hormones required by the body. The thyroid also produces another hormone called calcitonin which is responsible for keeping the bones healthy by providing it with calcium. A person is said to have a thyroid disorder when the gland does not produce enough hormones to allow the body to carry out various metabolic activities [1, 2, 3].

If the hormones produced are abnormally low then it is termed as hypothyroidism or underactive thyroid and if it abnormally high then it is termed as hyperthyroidism or overactive thyroid. Hypothyroidism causes a variety of symptoms including constipation, depression, fatigue, hair loss, fertility issues with females, and weight gain.

Hyperthyroidism is quite rare and causes a person to have diarrhea, problems with sleep, heat sensitivity, mood swings, irritability, and shakiness of hands [1, 2, 3].

On the other hand, cholesterol is a substance naturally produced in the body that is used to help digest fat by making bile acids. When there is accumulation of cholesterol in the arteries it results in variety of illnesses of which the most common is cardiovascular problems. Cholesterol travels through the body by binding itself to a protein. This is termed as lipoprotein. There are two types of lipoprotein, namely high density lipoprotein or HDL and low density lipoprotein or LDL [1, 2, 3].

While HDL is termed as good cholesterol as it helps the body to get rid of excess cholesterol from the blood. LDL is termed as bad cholesterol as it increases the risk of a person having cardiovascular problems [1, 2, 3]. The article below highlights the possible link between thyroid problems and cholesterol.

What Is The Link Between Thyroid Problems And Cholesterol?

The best way to understand the link between thyroid problems and cholesterol is to divide into two categories, i.e., in cases of underactive thyroid and cases of overactive thyroid.

Underactive Thyroid: T3 is a thyroid hormone that plays a crucial part in helping the liver get rid of any excess cholesterol in the body. When the thyroid gland is not able to produce enough T3 hormone this process of the liver filtering out excess cholesterol gets hampered. This results in accumulation of bad cholesterol and total cholesterol in the body. This establishes a clear link between an underactive thyroid and high cholesterol [3].

It has been estimated through various studies that approximately 12% of people with hypercholesterolemia have hypothyroidism. Research also shows that people who are newly diagnosed with high cholesterol undergo tests to look for hypothyroidism or an underactive thyroid. However, once the thyroid issue is addressed and medications are started the cholesterol levels become better and trend towards normalcy even without any cholesterol lowering medications [3].

Researchers state that even if the thyroid is mildly underactive then also it can lead hypercholesterolemia. It has also been observed that high cholesterol can be caused by elevated levels of TSH even if T3 and T4 levels are normal [3].

Overactive Thyroid: In cases of hyperthyroidism or overactive thyroid the effect is exactly the opposite. This means that a person with high levels of thyroid hormones will have low levels of cholesterol. However, there is no concrete proof that low levels of cholesterol pose any threat to the overall health of a person [3].

In conclusion, there is a clear link established between thyroid disorders and cholesterol. In fact, researchers have known the link between these two entities for decades but the studies done on this topic has thrown variable results where, in some cases, there was no correlation established while in others there was a significant link. The link between abnormal levels of cholesterol and thyroid problems is seen mostly in cases where people have an underactive thyroid or the thyroid gland is not producing enough T3 hormones. This hormone is crucial as it helps the liver filter out the bad cholesterol from the blood [1, 2, 3].

If the thyroid gland does not produce sufficient T3 hormone then this filtering process of the liver gets affected resulting in gradual accumulation of cholesterol in the arteries causing hypercholesterolemia which is a risk factor for various cardiovascular diseases. Thus people with newly diagnosed hypercholesterolemia undergo a thyroid test to look for an underactive thyroid as a cause for it [1, 2, 3].

Once hypothyroidism or underactive thyroid is addressed then in most cases the cholesterol levels improve significantly. Thus people who have hypothyroidism should regularly monitor their cholesterol levels and ensure they eat a healthy diet and exercise regularly to prevent development of hypercholesterolemia [1, 2, 3].

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