When cholesterol circulates in the blood, it is bound to protein. High density lipoprotein, or HDL, appears to protect against heart disease. Heredity plays a role in whether or not a person has more high density or low density lipoprotein. Levels of low density lipoprotein, that associated with increased risk, seem to be influenced by the amount of fat and cholesterol in the diet, but high density lipoprotein levels do not. Research shows that protective high density lipoprotein levels can be increased with exercise, weight reduction and by not smoking.
Cholesterol is found in cell membranes of animal foods.
Egg yolks and organ meats contain the most cholesterol. Meat and milk also contain some cholesterol. Cholesterol cannot be trimmed from meat like fat can, because it is distributed throughout. Low-fat milk products provide lower amounts of cholesterol than whole milk or cream. In countries where people have high cholesterol and high saturated fat intakes, blood cholesterol levels are higher and there are more cases of coronary heart disease.