Cholesterol is a substance that all animals, including humans, produce in the liver. It’s an important component of cell membranes and hormones and, in normal quantities, is necessary for good health.
So if cholesterol is such a good thing, why are so many of us concerned about having high cholesterol levels? The key phrase is “normal quantities.”
“The problem we encounter with cholesterol stems from the combined effects of heredity and diet. We not only produce our own cholesterol, but we also consume cholesterol through animal protein in our diet,” said Anna Sallee, assistant professor of nursing at Prairie View A&M University’s College of Nursing. “Because of this, some people have more cholesterol than their bodies need.”
Sallee said these individuals must be more cautious in the amounts of animal protein they eat. Animal protein includes not only meat, but animal products such as eggs, cheese and milk.
Of course, heredity and diet aren’t the only factors that affect your cholesterol level. Your age, blood pressure, amount of physical activity, and whether you smoke also figure in. Sallee said physical activity affects cholesterol level, because it enhances the production of “good” cholesterol.
What’s the difference between good and bad cholesterol? To understand that, you have to understand how cholesterol and proteins work together. Cholesterol is a lipid, and it circulates through the body attached to proteins. Together, the cholesterol and protein form a lipoprotein. There are two major types of lipoproteins: low density (LDL, or bad cholesterol) and high density (HDL, or good cholesterol).
“We teach our students to think ‘L’ for lousy and ‘H’ for happy to remember which is the good cholesterol,” Sallee said.
HDLs are good because they help clear out excess cholesterol from the blood stream, and LDLs are bad because they coat arterial walls.
“Cholesterol is a waxy, fat-like substance that builds up along blood vessel walls, eventually blocking the blood flow,” Sallee said. “The most commonly affected vessels are the arteries that feed the heart. If these arteries are blocked, a person can have a heart attack.”
Sallee said clogged arteries can affect other parts of the body as well, resulting in amputations, kidney failure and many other complications.
High cholesterol has no symptoms, so it is important to have cholesterol levels and other serum fats measured.
When you have your cholesterol “checked” you are most likely having all your serum (blood) lipids measured. Cholesterol levels can be obtained at any time, with or without fasting. However, cholesterol levels alone do not tell you enough about your health.
“You need to know if your cholesterol is high because you have high LDL or high HDL and what the ratio is between the two,” Sallee said. “An athlete may have a high cholesterol reading because his/her high level of activity actually causes a high HDL, which is good.”
Sallee recommends always requesting triglyceride (another type of fat found in the blood that has a similar effect on blood vessels as cholesterol) and lipoproteins measurements. For these tests, you must fast for at least 12 hours and not consume alcohol for 24 hours before testing.
“You want your LDL to be less than 130 mg/dl,” Sallee said. “Your goal should be less than 100. The desirable HDL is 37 to 70 mg/dl for men and 40 to 88 mg/dl for women, but your goal should be an HDL greater than 40. Triglycerides should be 40 to 190 mg/dl. Total cholesterol should be lower than 200.”
Sallee said high cholesterol levels are treated initially through changes in diet and exercise. If these measures do not lower the levels, the doctor will prescribe medication. The risk of heart damage is too great to allow high levels of these substances to continue.
You should start having your cholesterol and other lipids checked at age 20. If levels are in the safe range, you should be tested every five years. If levels are high, your physician will prescribe a plan of care that includes frequency of testing. Typically, an individual is tested about every six months until lipoprotein levels are in an acceptable range. If the levels are extremely high, testing may initially be done every three months.
For more information, Sallee recommends visiting Health Square's high colesterol site.
This information is provided as a service by Prairie View A&M University’s College of Nursing. If you have questions or would like more information, talk to your physician.
H.E.A.D.s Up is a monthly column that features articles on a wide array of Health, Exercise And Diet issues. Information for these articles is provided by health and wellness professionals from throughout the A&M System. If you have questions or story ideas for this column, email Ruth McMullan.