After my recent column on margarine and butter, a number of women asked me about cholesterol and fat. The scientific information on cholesterol and fat is confusing, so I asked my colleague, Dr. Benjamin Caballero, director of the division of nutrition at the Johns Hopkins School of Public Heath, to explain what we should be doing about cholesterol and fat in our diets to improve our health.
Why is there concern about cholesterol levels?
Studies have repeatedly shown that people with high blood cholesterol levels are at increased risk for coronary heart disease. The three most important risk factors for coronary heart disease are smoking, high blood pressure and high blood cholesterol.
Since heart disease is the leading cause of death for women in the United States, this is of great importance to us.
Q: How do you get high blood cholesterol?
The kind of genes you inherit and the fats and cholesterol you eat in your diet are directly related to the level of cholesterol in your blood.
What should your cholesterol level be?
Many doctors now screen patients routinely for cholesterol levels. The "desirable" level is below 200 milligrams of cholesterol per deciliter of blood. Levels between 200 and 240 are considered borderline, and levels above 240 are related to a risk of heart disease and may require steps to reduce the level.
Over half of the population of the United States has blood cholesterol levels above 200 and 25 percent have levels above 240. If your cholesterol is above 200, your physician also may get an additional test, called a "lipoprotein profile," to assess your risk.
What does the lipoprotein profile tell us?
A: Most cholesterol travels in the blood attached to proteins called lipoproteins. Low-density lipoproteins (LDL) carry cholesterol from the liver to everywhere in the body. By spreading cholesterol all around the body, LDL contributes to too much cholesterol in the arteries. We call LDL the "bad" cholesterol.
On the other hand, high-density lipoproteins (HDL) are the "good" cholesterol. They pick up cholesterol from all over the body and carry it to the liver so it can be disposed of. The actual risk of coronary heart disease is determined by how much HDL is available to remove circulating cholesterol, balanced by the amount of LDL that is spreading cholesterol around. Desirable levels of these lipoproteins is less than 130 milligrams per deciliter of blood for LDL and more than 35 milligrams per deciliter for HDL.
