Cholesterol, the mind, and the brain
It sounds like a no-brainer: The lower your cholesterol, the better your health. When it comes to coronary artery disease, conventional wisdom is truly wise; new guidelines call for reducing LDL ("bad") cholesterol levels to 70 mg/dL or lower for patients at the highest risk. But a man's heart and his head don't always agree. In fact, the relationships among cholesterol levels, psychological function, and neurologic disorders are complex and sometimes controversial. How do cholesterol levels and cholesterol-lowering drugs affect the mind and the brain?
Cholesterol in the brain
Despite its well-deserved notoriety as a cause of heart disease, cholesterol is essential for human health. It is the building block of steroid hormones, including the stress hormone cortisol and the male and female sex hormones, including testosterone and the estrogens. Cholesterol is also an essential component of the membranes that surround all human cells. More than simply holding cells together, these membranes have a crucial role in regulating cell function and allowing chemicals to pass into and out of cells.
Because cholesterol is so vital, the body does not rely on diet to provide it. In fact, most of the cholesterol in the blood is manufactured in the liver. Strict vegetarians who don't get any dietary cholesterol have admirably low blood cholesterol levels that reduce their risk of heart disease while providing plenty of cholesterol to keep their cells happy and their hormones flowing. Statin drugs reduce the liver's cholesterol production by targeting the enzyme HMG-CoA reductase; and by lowering blood cholesterol levels, they protect arteries from damage.