Underactive thyroid a little-known cause of high cholesterol
Q. My doctor told me I have an underactive thyroid. Could this be affecting my blood cholesterol level?
A. Yes. A sluggish or underactive thyroid-- called hypothyroidism--an slow down your body's metabolism, as well as delay clearance of cholesterol and triglycerides from blood, resulting in high blood levels of triglycerides and LDL's ("bad" low-density lipoprotein cholesterol).
In fact, over 90% of people with hypothyroidism have elevated cholesterol, triglycerides or both. They are usually treated with synthetic thyroid hormones like levothyroxine (Synthroid, Levoxyl, Euthyrox), which help normalize lipid levels.
Hypothyroidism is a surprisingly common problem, affecting five times as many women as men. Many people are unaware they have it. One of the first signs of thyroid failure is an increase in the blood level of thyroid stimulating hormone (TSH). By age 50, 10% of women have elevated TSH; by age 60, as many as 17% of women and 9% of men do. Other symptoms include sluggishness, chills, lack of motivation and diminished alertness. If left untreated, hypothyroidism can increase the risk of heart disease.
If you are diagnosed with hypothyroidism, you may be told to go easy on foods that can interfere with thyroid function if consumed in excess----dubbed "goitrogens." These include cabbage, cauliflower, kale, Brussels sprouts, broccoli, kohlrabi, mustard greens and rutabaga. But this is not a concern if you're taking thyroid medication. You should, however, avoid supplements containing iron, as they can interfere with the body's ability to absorb the medication.
Because many adults have hypothyroidism but don't know it, the Thyroid Foundation of America suggests women over 50 and men over 60 get a blood test to measure TSH. High TSH levels indicate an underactive thyroid, while low levels can signal overactivity. A normal TSH level, however, does not guarantee your thyroid is functioning fine. If you constantly feel fatigued, see your health care provider or an endocrinologist for additional tests.