Most people know that cholesterol levels are tied to heart disease, and affected by diet, exercise, and genes. Too much dietary fat and cholesterol levels can skyrocket. But cholesterol is also tied to thyroid levels and the body’s overall metabolism. Understanding this link can help to keep the body’s engine running and protect your heart health.
The thyroid gland (located in the front of your neck) produces vital thyroid hormone that is very important in regulating your body’s metabolism. One key effect of this hormone on cholesterol is that it helps prime the liver to breakdown circulating cholesterol. It also stimulates other enzymes to clear triglycerides from the body.
The thyroid acts like the body’s accelerator pedal. When the thyroid produces more thyroxine, it is similar to pressing the accelerator and revving up the engine. When the thyroid doesn’t produce enough thyroxine, it is as though your foot is off the gas; the body slows down. When the thyroid slows down (hypothyroidism), it also slows down the body’s ability to process cholesterol. This processing lag is largely explained by a reduction in the number and activity of what are known as LDL receptors.
LDL receptors help remove bad cholesterol from the body; when the number of receptors decreases, LDL accumulates in the bloodstream, acting to increase both LDL and total cholesterol levels.
Hypothyroidism, underactive thyroid, often causes weight gain. Excess weight leads, in turn, to a rise in your cholesterol levels. A cholesterol blood test includes four results: triglycerides, LDL cholesterol, high-density lipoprotein — HDL or “good” cholesterol — and total cholesterol. Healthy triglycerides measure 150 mg/dl — milligrams per deciliter of blood — or less. You should keep LDL cholesterol below 100 mg/dl, or below 70 mg/dl if you face a high risk of heart disease. Aim to keep your heart-friendly HDL cholesterol above 60 mg/dl and your total cholesterol below 200 mg/dl.
The good news is that high cholesterol caused by hypothyroidism is highly treatable. Much of the time, thyroid patients can avoid using cholesterol-lowering drugs simply by treating their condition. People with an overactive thyroid gland, or hyperthyroidism, also must be concerned about cholesterol. Their condition causes a high metabolic rate that can artificially lower cholesterol levels. People being treated for hyperthyroidism must watch their cholesterol levels as their metabolism returns to a normal level. Both hyperthyroidism and hypothyroidism are easily treated through medication.
High cholesterol is a well-known health problem among Americans, particularly those at risk for stroke or heart disease. By comparison, thyroid disease is a relatively obscure ailment, with many people unable to say where the gland is and what it does. What many people also don’t know is that a malfunctioning thyroid gland can cause high and potentially deadly levels of cholesterol in the blood.
If you have symptoms of a thyroid problem and your cholesterol levels are high or low, see your doctor. You’ll get blood tests to measure your level of TSH and your level of a thyroid hormone called thyroxine. These tests will help your doctor find out if your thyroid is overactive or underactive.
For an overactive thyroid, your doctor will give you radioactive iodine to shrink the gland or medicines to reduce thyroid hormone production. A small number of people who can’t take anti-thyroid drugs may need surgery to remove most of the thyroid gland.