Cholesterol, High Health Article

Definition

High cholesterol (hypercholesterolemia or hyperlipidemia) refers to the presence of higher than normal amounts of total cholesterol circulating in the bloodstream. Cholesterol is a fatty substance (lipid) that is essential to the body as protection for the walls of the vasculature (veins and arteries) and linings of body organs, a component in the manufacture of hormones, and a factor in the digestion of consumed fats in foods. It is manufactured in the liver and carried throughout the body in the bloodstream. Cholesterol is also a component of animal tissue and can be consumed in products such as meat, eggs, fish, milk, and milk products such as butter and cheese. Elevated cholesterol levels can result in the accumulation of fatty deposits on blood vessel walls, narrowing veins and arteries and impeding blood flow to the heart, brain, and other organs.

Description

Cholesterol has both a good form and a bad form that add up to total cholesterol when measured together. The body needs cholesterol to produce bile acids that help digest fats ingested in food, make hormones, protect cell walls, and participate in other processes that help maintain health. Ironically, cholesterol can also be a problem, if too much is manufactured by the liver or consumed through the diet and not metabolized or used. The utilization of fat in the body, or fat metabolism, is a complex process, complicated even more by abnormally high levels of cholesterol found circulating in the blood. Although high cholesterol is not often found in young children, it may begin to develop in adolescents or young adults either as an inherited condition or through unhealthy eating habits and can continue into adulthood, creating potentially serious health problems. High cholesterol levels and fatty deposits in veins and arteries (atherosclerosis) have been found during autopsies of children who have died of accidents and other causes.

The liver metabolizes cholesterol, including the cholesterol obtained from foods in the diet. The components of cholesterol are then carried into the bloodstream bound to the surface of certain lipoproteins. Low-density lipoproteins or LDLs carry about 75 percent of the cholesterol into the blood and high-density lipoproteins carry the other 25 percent. LDL is the lipoprotein known as bad cholesterol because it consists primarily of cholesterol and is most associated with the development of vascular disease. Cholesterol is not the major part of HDL, the so-called good cholesterol, and the presence of higher amounts of HDL in the blood actually helps reduce the more harmful LDL levels. Another lipoprotein, very low-density lipoprotein (VLDL), carries harmful fats known as triglycerides but does not carry a significant amount of cholesterol. Triglycerides are also measured as part of a lipid profile and high levels are associated with vascular disease and heart disease. Cholesterol levels in blood serum vary considerably from day to day and even from one time of a day to another related to the consumption of fats in the diet.

High LDL (low-density lipoprotein) is a major precursor of vascular disease and heart disease. This form of cholesterol combines with triglycerides, cellular waste, calcium, and scar tissue to form a waxy deposit (plaque) on the inner walls of large and medium-sized arteries, causing a condition called hardening of the arteries (atherosclerosis or arteriosclerosis). Plaque typically builds up as people get older, more in some people than others depending on lifestyle (diet, exercise, alcohol consumption, and smoking) and heredity. The result may be a narrowing (stenosis) or blockage of blood vessels, interrupting the essential flow of blood and oxygen to the heart, brain, abdominal organs, and peripheral circulation to the arms and legs. Eventually this can lead to heart attack or stroke, permanent damage to the heart or brain, and life-threatening complications.

The population as a whole is at some risk of developing high LDL cholesterol. Specific risk factors include a family history of high cholesterol, obesity, coronary artery disease (atherosclerosis), stroke, alcoholism, diabetes, high blood pressure, and lack of regular exercise. The chances of developing high cholesterol increase after the age of 45. One of the primary causes of high LDL cholesterol is a combination of too much fat and sugar in the diet, especially through the consumption of fast foods and refined or packaged foods, a problem that has been especially true in the United States since the advent of manufactured foods. A renewed interest in whole foods may help to alter the prevalence of high cholesterol and vascular disease.

An increased serum cholesterol may be found in familial hyperlipidemia or hypercholesterolemia, underactive thyroid (hypothyroidism), untreated diabetes, a high-fat diet, pregnancy, heart attack, stress, and certain liver conditions (cirrhosis). A decreased level may be found in liver dysfunction, overactive thyroid (hyperthyroidism), malabsorption, malnutrition, or advanced cancer, among other conditions.

Although high cholesterol has been shown to be a risk factor for developing atherosclerosis in adults, with associated increased morbidity and mortality, studies have not indicated that high cholesterol in children and adolescents is related to the development of specific illness or increasing mortality in adulthood. There is strong evidence in numerous research studies, however, that a family history of high cholesterol, atherosclerosis, heart attack, or stroke increases the risk of a child developing high cholesterol levels.

High cholesterol is often diagnosed and treated by general practitioners or family practice physicians. In some cases, the condition is treated by an endocrinologist or cardiologist. Pediatricians will generally refer affected children to the appropriate specialist.