Coronary heart disease (CHD) is the primary cause of death in the United States and many developed countries. CHD is caused by the narrowing of the blood vessels that supply nutrients and oxygen to the heart. The main reason for his narrowing is atherosclerosis, a buildup of fatty streaks inside the walls of arteries. Hyperlipidemia-a risk factor for developing atherosclerosis and heart disease-refers to the elevation of cholesterol and/or triglycerides, one of the main forms of fat in the body. The good news is that its negative effects can be avoided by lowering cholesterol levels.
What is cholesterol?
Cholesterol is a naturally occurring substance that is essential to the body. It is the substance needed to make bile (necessary for absorption of food) and some hormones (steroid hormones). Cholesterol is also used to form cell membranes; it is, therefore, important that it is available to all cells. The cells receive cholesterol from two sources: 1) Cholesterol produced by the liver (the endogenous source) and 2) obtained from the diet (the exogenous source).
Cholesterol does not travel alone in the blood but is present as one component of blood particles called lipoproteins. Lipoproteins contain cholesterol, triglycerides (TG), and proteins. The more cholesterol and triglycerides present within a lipoprotein, the less dense it is. These lipoproteins are thus categorized by size, fat content, and density. The three major lipoproteins found in blood are as follows:
- very low-density lipoproteins (VLDL).
- low-density lipoproteins (LDL), also known as the bad cholesterol.
- high-density lipoproteins (HDL), also known as the good cholesterol.
LDL cholesterol contributes to atherosclerosis, which is why LDL cholesterol is the primary target of cholesterol-lowering medicines.
Hyperlipidemia signs and symptoms
- Yellowish nodules of fat in the skin beneath eyes, elbows and knees, and in tendons.
- Enlarged spleen and liver (some types).
- Whitish ring around the eye pupil (some types).
There are two categories of hyperlipidemia: primary and secondary. The primary type is inherited, while the secondary type develops later in life due to increased dietary intake, medical conditions, and medications.
Medical conditions that may cause lipid problems include diabetes, alcoholism, obesity, lupus, a kidney disease called nephrotic syndrome, and low thyroid function (hypothyroidism).
Some of the medications that increase cholesterol are birth control pills, cyclosporine, corticosteroids, thiazide diuretics, isotretinoin, and some beta-blockers. Therefore, by eliminating the secondary causes, cholesterol may be reduced.
The desirable values for different lipids are as follows. To be in the desirable range, the cholesterol level should be less than 200 mg/dl, the LDL level should be less than 130, the TG level should be less than 200, and the HDL level should be greater than 60. Levels that are considered abnormal are total cholesterol greater than 240, LDL greater than 160, TG greater than 400, and HDL of less than 35.
The National Cholesterol Education Program (NCEP) has developed guidelines for cholesterol management, which has two goals. The first goal is prevention of atherosclerosis in individuals who have high cholesterol but have not yet developed coronary heart disease (CHD). According to the NCEP, risk factors that should be considered include the following:
- age of over 45 years for men and over 55 years for women
- a family history of CHD
- high blood pressure
- cigarette smoking
- low good cholesterol (HDL)
- high bad cholesterol (LDL).
For individuals who have these risk factors, the prevention of CHD focuses on diet and/or early treatment with medication. If the good cholesterol level (HDL) is greater than 60, then the treatment may be less aggressive than it would be if HDL was low.
The second goal focuses on treatment of individuals who have already developed CHD. At this point the physician will implement a very aggressive treatment that includes diet and medication. Therefore, the decision to start diet- or drug therapy depends on the level of LDL, other risk factors for heart disease, and the presence or absence of CHD.
There are four classes of lipid-lowering medications. They are:
- Bile acid binding resins, which include cholestyramine (Questran) and colestipol (Colestid), decrease LDL cholesterol by about 20 to 35 percent. They work by binding to cholesterol in the intestines and preventing its absorption. Because these drugs may increase triglycerides, they should not be used in people with high TG. The side effects of the drugs include gastrointestinal symptoms, which include constipation, bloating, nausea and gas. Increasing dietary fiber can minimize constipation. Other medications should either be taken one hour before or four to six hours after taking the resin because the resins can bind to medications and alter their effect. These drugs are available in dry powder form, which should be mixed with at least three ounces of hot- or cold liquid (such as juice, milk, soda, or soup). To make it taste better, the dose can be mixed in a pitcher of juice and kept in the refrigerator.
- Niacin (vitamin B3) is ideal for people with combination lipid disorder since it decreases LDL and TG and increases HDL. It is available over the counter at a low cost. The main drawback to its use is the side effect, which includes flushing, itching, and headache. Taking aspirin 30 minutes before the dose can reduce these side effects. Niacin can also cause fatigue and gastrointestinal symptoms including nausea, stomach discomfort, and worsening of stomach ulcers. Taking the drug with food may decrease the stomach discomfort.
- Fibric acid derivative, gemfibrozil (Lopid), is mostly used to decrease triglyceride levels. It is associated with 25-40% reductions in TG. Major side effects include gallbladder stones and muscle- and stomach pain. Gemfibrozil should be taken 30 minutes before meals.
- "Statins" are the most potent group of drugs available. They lower LDL and TG levels and increase HDL. The drugs in this group include atorvastatin (Lipitor), cerivastatin (Baycol), fluvastatin (Lescol), lovastatin (Mevacor), pravastatin (Pravachol) and simvastatin (Zocor). The statins are well tolerated, and side effects are uncommon. Occasional headache and constipation, abdominal pain, and gas are experienced by some, but these symptoms usually disappear with continued use. Some people may experience muscle pain and weakness. Lovastatin should be taken with food to increase absorption. Except for atorvastatin, these medications work best when taken in the evening.
Other cholesterol-lowering drugs include fish oil (omega 3), which is mainly used for people who have high TG and who are not controlled with niacin or gemfibrozil. In addition, estrogen replacement therapy has been used in postmenopausal women to reduce LDL and increase HDL.
- Many medications are now utilized to control blood lipids. Work with your doctor to find effective treatment.
- Medications to treat underlying diseases, such as diabetes or thyroid conditions.
- Don't take oral contraceptives. Use other forms of birth control.
Zocor (Simvastatin), Mevacor (Lovastatin), Pravachol (Pravastatin), Crestor (Rosuvastatin), Lopid (Gemfibrozil), Zetia (Ezetimibe), Tricor (Fenofibrate)
- No restrictions unless tendons are weakened by fat deposits or you have coronary artery disease.
- A regular exercise program is helpful for reducing weight, and controlling stress, and it might help in increasing the body’s ability to clear fat from the blood after meals.
If the condition has not reached the point to warrant hospitalization for intravenous fluids, follow these instructions:
- Eat a diet that is low in fat (particularly saturated fat). Get medical advice on proper diet.
- Lose weight if you are overweight. The more overweight you are, the more lipids your body produces.
- Don't drink alcohol.
Change in lifestyle
The main therapy to decrease cholesterol is to implement a low-fat, low-cholesterol diet.
In a typical American diet, about 35% of calories are from fat. The NCEP Step 1 Diet, which is recommended for all Americans, restricts the total fat intake to 30% of daily calories, saturated fat to 10%, and dietary cholesterol to 300mg/day.
It is important to minimize saturated fats by trimming fat from meats, consuming low-fat or non-fat dairy products, and avoiding oils containing lard, coconut, palm, or bacon fat. Foods low in saturated fat-such as bran, nuts and olive oil-should be substituted.
Also, intake of fresh fruits and vegetables should be increased.
When further diet therapy is needed, the NCEP Step 2 Diet recommends limiting total fat intake to 30% but also limiting saturated fat to less than 7% and dietary cholesterol to 200mg/day.
Other lifestyle changes include losing weight, not smoking, and exercising.
Last updated 4 April 2018