Cholesterol and Thyroid Link

At the clinic, we often see that thyroid hormones and cholesterol/lipid levels are strongly linked in patients.

Clinical studies have shown in the past that treating patients with thyroid hormones can improve cholesterol levels. 

However, it has never been clear that suboptimal thyroid hormone levels were directly responsible for causing high cholesterol since so many other factors are involved when a patient is hypothyroid. For example, patients with hypothyroidism may be exhausted, and unable to exercise or cook nutritious meals for themselves.

To clarify this point, in a recent study on thousands of people, researchers used mendelian genetics to understand more about the link between thyroid and cholesterol. The researchers looked at genetic alterations in thyroid blood markers including TSH, free T4, free T3 and Thyroid Peroxidase Antibodies.

What they found was quite interesting: genetically altered levels of TSH and reduced ratios of free T3: free T4 caused increased total cholesterol and LDL (“bad” cholesterol) in the blood.

It is important for all patients with elevated lipids to have a comprehensive thyroid assessment including TSH, free T3, free T4, Anti TPO and Anti TG. And the opposite is true – thyroid patients should have their lipid levels assessed regularly!