In the early stages of the cholesterol education campaign, consumer information was very one-dimensional. People were told to eliminate cholesterol-containing foods (such as eggs and red and organ meats) from their diets so they could reduce the amount of cholesterol in their blood and ultimately lower their risk for heart disease.
Today, the emphasis has shifted. We are still concerned about dietary cholesterol but our knowledge has become more fine-tuned. Today, we also are concerned about the amount of cholesterol that we inherited from our parents that's already in the bloodstream and what effect this has on cardiovascular disease.
As a result, millions of Americans are having their cholesterol levels tested. But, the experts warn that the results of these tests must be closely scrutinized--considered as just one component for determining risk--and not used to impose strict dietary and life-style changes that may be unnecessary.
Testing has always been part of hospital admission exams. But today, to support consumer interest, mini-testing labs appear in shopping malls, at health clubs and as part of work-site health fairs. Frequently, however, the test results are misinterpreted or misrepresented (even by the laboratories administering the tests), leading to self-medicating and the elimination diets so prevalent in the past.
Different Factors Involved
Much data has been collected to avoid this scenario. Scientists concur that for a segment of the population, higher levels of cholesterol in the diet lead to increased risk of death from heart-related disease. But determining the cholesterol level is just the first step toward determining risk. Environmental and hereditary factors also contribute.
Many diseases are the result of a genetic predisposition plus an environmental factor that works on this genetic tendency, according to Dr. Roger Williams, a University of Utah professor of internal medicine and researcher specializing in cardiovascular genetics. Environmental contributors include smoking, lack of exercise and obesity.
Based upon his research, Williams states that early death from heart disease may not be certain fate for the millions of Americans with a strong family history of early heart attacks. He claims there is a large segment of people with a genetic predisposition to premature heart disease (they have blood cholesterol levels above 300 or are hypertensive), but with careful tracking of their family medical history, proper diet and drug therapy, it is possible to add as much as 20 years to their lives.
"Family history is a powerful predictor," Williams said, "That's why it's so important for people to know the medical history of their parents, grandparents, brothers and sisters. If these relatives have died, the treating physician needs to know what killed them and how old they were.
'Changing the Environment'
"Once you evaluate the genes, you begin treatment by changing the environment: Eat less fat, quit smoking, get some exercise and reduce stress for starters. If that's not enough, then use cholesterol-lowering drugs," he advised.
But first, a person must be determined to be at risk. To begin the analysis, a finger-prick blood test is administered to measure the amount of cholesterol (in milligrams) in 100 milliliters of blood. Results are categorized according to the following figures, based on guidelines set by the National Heart, Lung and Blood Institute: Desirable--less than 200 milligrams/100 milliliters; Borderline-High--200-239 mg/100ml; High--240 mg/100ml or more.
Those with a cholesterol level above 200 should be given the test again. The average of the two determines the next step. If the total cholesterol level is above 200, a lipoprotein profile is required. This test will measure low-density lipoproteins (bad cholesterol) and high-density lipoproteins (good cholesterol). If either one is abnormal, a family history may be required to determine risk for cardiovascular disease.
LDL cholesterol circulates through the body making its type of cholesterol available for building cell membranes, hormones or nerve endings. Its concentrations in the blood may be increased by consuming diets rich in saturated fatty acids or substantial amounts of cholesterol. One theory is that the linings of blood vessels serve as a stopping place for LDL, where it seems to cause damage.
HDL cholesterol is responsible for transporting cholesterol in the body and the effect of diet on it is not yet clear. It too circulates through the body for a time, picking up additional cholesterol along the way, but it eventually arrives at the liver where its cholesterol is incorporated into bile and excreted.
An Inherited Disorder
More than 1 million people suffer from "familial hypercholesterolemia," an inherited disorder marked by extremely high LDL cholesterol levels, Williams said. They have high blood cholesterol by age 1 or 2 and their average age for heart attack is 45.