Cholesterol is so often treated as poison that one might be tempted to wonder what purpose it serves. It is produced in the body, after all, which suggests that it is not completely useless or entirely malevolent. And in fact, while the tendency is to assume less is better, the reality is more complicated than that. Modern science knows of several important functions served by cholesterol in the body—functions that can be negatively affected by statin drugs that lower cholesterol levels.
Cholesterol is used in the construction of hormones, the chemical signals used to regulate most of what the body does. Hormones guide things like breathing and digesting food and turning it into energy. Bile, which is also part of the digestive process, is another cholesterol product. Even so-called bad cholesterol is used by the body in this way.
Another thing cholesterol does is helping to keep the lens of the eye clear and free of cataracts. The clouding in the eyes caused by characteristics results, in many cases, from flaws in cell regeneration, which cholesterol prevents. That may be why, in a recent study, statin users had as much as a 27 percent higher risk of cataracts than non-users. Cataract risk increases with age in any event, with nearly three in four 80-year-olds having had cataracts at some point.
Statin drugs do two things. They prevent the formation of cholesterol within the body, and they increase absorption of cholesterol that’s already there. Patients who take statins have lower cholesterol levels in part because more of it is simply metabolized. The result of both modes of action is that there’s less cholesterol to form arterial plaque and cause heart disease, but there’s also less available for eye health, resulting in heightened cataract risk.
Other side effects of statin drugs include the possibility of muscle weakness, muscle inflammation, and liver disease, as well as an increased likelihood of type 2 diabetes. Because of the risk, some doctors are moving away from prescribing statin drugs, and there are concerns that they are overused. In many people, dietary changes are sufficient to reduce high cholesterol, without levels dropping so far as to cause problems.