When it comes to ensuring a fit and functioning brain, cholesterol is an essential compound, but a complex one as well. The waxy fat-like substance comes in two forms whose interaction needs to be carefully balanced in order to ensure maximum health.
Cholesterol is a key component of cellular membranes and helps regulate cellular functions. The trick is to maintain healthy levels of both beneficial “good” HDL (high-density lipoprotein) cholesterol and potentially harmful “bad” LDL (low-density lipoprotein) cholesterol. When HDL levels are too low and LDL cholesterol levels soar—a condition often referred to as “high cholesterol”—there’s trouble in store.
WHAT YOU CAN DO
For many people, a healthy lifestyle can lower cholesterol levels without the need for medications. To lower cholesterol levels:
- Maintain a healthy weight.
- Exercise. If your doctor approves, try to get at least 30 minutes of exercise daily.
- Limit dietary sources of cholesterol—foods like fatty meats, poultry skin, organ meats, high-fat dairy products, and oils high in saturated fats, such as coconut, palm and palm kernel oil.
- Restrict consumption of saturated and trans fats. Replace them with healthy fats such as olive and canola oils, and omega-3 fats from fish and fish oil. Try to limit fat intake to 30 percent or less of your total daily calories.
- Consume fiber. Boost your intake of fiber-rich foods, such as whole grains, nuts, legumes, fruits, and vegetables.
- Reduce salt intake to 2,300 mg or less per day
In the brain, cholesterol forms the myelin sheath that insulates nerve fibers responsible for relaying impulses through the nervous system, and promotes the formation of communication points between brain cells known as synapses. But LDL plaque accumulation in cerebral blood vessels can reduce the flow of oxygen and nutrients to brain tissue. Too little HDL cholesterol helps lead to this accumulation of “bad” LDL and represents a marker for incipient heart disease. Insufficient HDL also may injure brain cells and interfere with their ability to connect and communicate with other cells.
“Keeping your cholesterol levels within healthy limits is an important part of staying physically and mentally fit, especially as you grow older,” says Pradeep Natarajan, MD, MMSc, Director of Preventive Cardiology at MGH. “Fortunately, unless you have genetic factors that make cholesterol hard to control, you should be able to maintain proper cholesterol levels through a healthy lifestyle (see What You Can Do) and management of medical conditions.
“If you develop high cholesterol despite these lifestyle strategies, medications such as statins usually can help you bring it under control.”
Exciting new research suggests that one day it may be possible to banish the problem of high cholesterol by harnessing the brain’s immune system. Researchers have created a vaccine that causes mice to produce antibodies to an enzyme that contributes to the buildup of LDL cholesterol. According to a paper published June 20, 2017 in the European Heart Journal, the vaccine had long-term benefits, including reducing the animals’ total cholesterol by 53 percent, reversing damage to blood vessels by 64 percent, and lowering markers of inflammation.
“Normal” Cholesterol Levels
Cholesterol levels are measured through a medical test called a lipidprotein panel in which a sample of the patient’s blood is analyzed after fasting. The test measures LDL and HDL cholesterol, as well as fats called triglycerides (a type of fat derived from the diet that is deposited as body fat) and total cholesterol (the total of HDL and LDL measures plus 20 percent of triglycerides). The measures are calculated in milligrams of cholesterol for each deciliter of blood (mg/dL). People with a history of heart attack or stroke may be advised to maintain lower cholesterol levels than those recommended for healthier people. See the chart on this page for optimal cholesterol levels for men and women.
For both men and women a total cholesterol level of under 200 mg/dL is considered excellent, 200-239 mg/dL is considered borderline high, and 240 mg/dL or above calls for medical evaluation and analysis. Triglyceride levels above 150 mg/dL should be lowered.
“To protect your brain and your overall health, your cholesterol should be tested in your 20s, and every three to five years after that if your levels are very high or you have a history of cardiovascular problems,” says Dr. Natarajan.