Cholesterol is a white, waxy, fatlike substance. Although we usually think of it as found only in the bloodstream, it is actually present in all tissues in humans and other animals. It is thus present in all foods from animal sources. It it not present in any plants.
Cholesterol is essential to life: among other things, it is used in the outer membranes of cells; as a fatty insulation sheath around nerve fibers; and as a building block for certain hormones.
Despite its importance to life, cholesterol isn’t an essential nutrient—you don’t have to consume any to stay healthy. Most of the cholesterol in your bloodstream is manufactured in your body—primarily by the liver—from the fats, proteins, and carbohydrates you eat.
Just how cholesterol is distributed throughout the body is not entirely clear, but researchers hypothesize that the mechanism works in this way: the liver puts together packages called lipoproteins, made of proteins, cholesterol, and triglycerides (fats either made by the body or derived directly from foods). Low-density lipoprotein, or LDL, carries cholesterol throughout the system, dropping it off where it can be used for cell metabolism. Cholesterol carried by LDL that is not used, broken down by the liver, or excreted is left to circulate in the bloodstream, where it accumulates in the arterial walls. Nodules, called plaques, are eventually formed, decreasing the flow of blood over time—a condition known as atherosclerosis—and favoring the formation of blood clots. This may ultimately cut off the flow of blood; in the coronary arteries, this leads to a heart attack, and in the cerebral arteries, a stroke.
The liver makes another molecular package known as high-density lipoprotein, or HDL. Like the other lipoproteins, HDL is composed of triglycerides, protein, and cholesterol, but HDL carries less cholesterol than LDL. As it circulates through the bloodstream, HDL seems to have the beneficial capacity to pick up cholesterol and bring it back to the liver for reprocessing or excretion.
In simple terms, then, LDL brings cholesterol into the system, so it’s often called “bad” cholesterol, and because HDL clears cholesterol out of the system, it has been dubbed “good” cholesterol. HDL (as well as LDL) is formed only in the body. You can’t eat “good” cholesterol; no type of cholesterol you eat is good for you.
- Cholesterol and heart disease. Generally speaking, an elevated total cholesterol level, along with a high LDL level, is associated with an increased risk of heart disease. Low HDL, defined as less than 35 milligrams per deciliter (mg/dl), is also considered a risk factor for heart disease. One study by researchers in Israel and at Case Western Reserve University in Cleveland showed that the risk of dying from heart disease was 38 percent higher in men with HDL under 35, even if their total cholesterol was below 200. Stroke risk in such men was higher, too.
The higher your HDL, the better. An elevated HDL level, defined as 60 mg/dl or more, is considered protective against heart disease. (Female sex hormones tend to raise HDL; this may help explain why women are usually protected against atherosclerosis during their childbearing years, when estrogen production is high.)
Experts believe that to be at low risk for heart disease, adults should reduce their total blood cholesterol levels to less than 200 mg/dl. While there is no magic number—a point at which your blood cholesterol level automatically passes from safe to dangerous—the risk of heart disease rises continually with increasing levels of blood cholesterol, though it doesn’t rise markedly until levels exceed 200 mg/dl. And the rate of coronary heart disease begins to accelerate rapidly above the 220 mg/dl level. Thus, many researchers believe that cholesterol levels should be as low as possible; well below 200 mg/dl is excellent.
Some experts question whether high blood cholesterol levels cause heart disease in everybody, and certainly your cholesterol level needs to be put in perspective within your total risk scenario for heart disease, based on such factors as age, sex, and health habits like exercise levels and whether you smoke. But there is substantial evidence that, in most cases, the connection between high blood cholesterol levels and heart disease is as incontrovertible as the link between smoking and lung cancer. This connection is strongest in men under 50 years of age. For young women and for everybody over 50, the link is weaker but still significant.
Who’s At Risk for Elevated Cholesterol?
The chart at right shows guidelines for total cholesterol as well as HDL (“good”) and LDL (“bad”) cholesterol for people free of coronary artery disease, or CAD. (The recommended total and LDL levels for people with CAD are lower.) The chart also indicates desirable levels of triglycerides—fats similar to cholesterol that, at elevated levels and especially in combination with low levels of HDL, may increase the risk of a heart attack. Triglyceride counts are also used in calculating LDL levels.
In the United States, cholesterol is measured in milligrams per deciliter (mg/dl) of blood. In Canada and many other countries, it’s measured in millimoles per liter (mmol/L). The latter is known as the International System. (To convert from milligrams to that system, multiply the number by 0.0259. To convert from millimoles to milligrams, multiply by 38.67.)
| Total Cholesterol | |
| HDL Cholesterol | |
| LDL Cholesterol | |
| Triglycerides |
Symptoms of High Cholesterol
There are no obvious symptoms for elevated levels of blood cholesterol, but the problem is linked to other conditions that have recognizable symptoms, including chest pain (angina) or heart disease, stroke and high blood pressure.
What Causes High Cholesterol?
A diet rich in cholesterol and—even more significantly—in saturated fat can increase your blood cholesterol level. (Sources of saturated fat include beef, butter, whole-milk dairy products, dark meat poultry, poultry skin, and coconut, palm, and kernel oils.) Many other factors affect your blood cholesterol level, and some people, no matter how small their fat and cholesterol intake, may continue to have high blood cholesterol levels because of genetic disorders, diabetes, or other metabolic diseases. For most people, though, diet remains the first defense against elevated blood cholesterol.
Other factors that can raise cholesterol levels are excess weight (each pound gained adds to total blood cholesterol) and smoking (which increases total cholesterol and decreases HDL cholesterol).
Before menopause, women tend to have higher HDL levels than men of the same age, and some researchers think that the higher HDL levels (as well as lower LDL) may be linked to estrogen. At menopause, estrogen production declines, and so does HDL.
Cholesterol Testing Guidelines
According to guidelines from the National Cholesterol Education Program (NCEP), all adults over the age of 20 should be tested for HDL and total cholesterol at least once every five years. Some people should be retested more frequently.
- If your total cholesterol is in the desirable range and your HDL is above 35 mg/dl, you can wait up to five years to have them rechecked. If your total cholesterol is borderline-high and your HDL is above 35 mg/dl, you should be rechecked in a year or two.
- If your total cholesterol is borderline-high or high and/or your HDL is below 35 mg/dl, especially if you have two or more risk factors for coronary artery disease (CAD), you should have a complete lipid profile (which requires fasting overnight) to determine LDL. Then, if your LDL is in the desirable range, you can wait up to five years to be retested. But if your LDL is borderline-high or high, and depending on your other risk factors, you’ll need to be retested annually as well as modifying your diet and take other steps to reduce your risk of CAD.
Note: Calculating LDL isn’t simply a matter of subtracting your HDL from your total cholesterol. The blood fats known as triglycerides figure into the equation for arriving at total cholesterol and are used in deriving LDL.
Risk Factors for High Cholesterol
The recommendations for testing are more stringent if you have other risk factors for CAD besides high cholesterol and/or low HDL. These risk factors are age, family history of premature CAD (a heart attack in your father before age 55, in your mother before age 65), smoking, high blood pressure, and diabetes. The guidelines are even stricter for those who already have CAD: for instance, your LDL should be below 100, rather than 130.
Men and Women and High Cholesterol
Women need to be monitored as carefully as men. But women tend to develop CAD about a decade later than men do, so while age is considered a risk factor for men starting at age 45, for women it’s at age 55. Women over 55 who have high cholesterol should make as great an effort as men to reduce it.
The Elderly and High Cholesterol
People in their 70s or even older should be treated just like people in their 50s or 60s, according to the NCEP guidelines. It is true that blood cholesterol levels naturally start to decline after age 75. But a recent report from the National Cholesterol Education Program found that nearly three-fourths of older people have substantial cholesterol build-up in their arteries. To reduce heart attack risk, therefore, it is important to have your blood cholesterol checked every five years even if you’re over 70. If your cholesterol is high, you and your physician should discuss your other risk factors, lifestyle changes to lower cholesterol levels, and whether to consider taking cholesterol-lowering medication.
Children and High Cholesterol
According to the NCEP, only children who have a family history of very high cholesterol levels and/or heart disease—particularly those with a parent who suffered a heart attack before age 50—should be tested. That includes as many as one-quarter of the nation’s children. Many authorities have concluded that screening all youngsters is unnecessary, since high blood cholesterol levels in childhood do not necessarily predict high levels later in life. But all children, whatever their family history, can benefit from a low-fat, heart-healthy diet after age two.
What If You Do Nothing?
A high total cholesterol level isn’t likely to decrease significantly unless you make some or all of the lifestyle changes described below, particularly those regarding weight control and diet. Some individuals may also require cholesterol-lowering medication to control their cholesterol levels.
Should You Take A Cholesterol-Lowering Drug?
Unfortunately, because of genetics, not everyone with high cholesterol responds to a low-fat diet—though the vast majority do, and the higher the cholesterol level to begin with, usually the greater the response. But many other people simply can’t stick to a low-fat diet. (Likewise, not everyone with a low level of HDL is able to raise HDL through lifestyle changes.) If your cholesterol level remains unchanged after several months of effort at lifestyle changes, your doctor may prescribe a cholesterol-lowering drug, particularly if you have other risk factors and/or symptoms of CAD.
Not long ago, such medications were recommended only for people who could not reduce their cholesterol by any other means and who have significant risk factors for, or symptoms of, heart disease. However, some new studies have suggested that even healthy people with desirable, but not optimal, cholesterol levels can reduce their risk of a heart attack by taking “statin” drugs, the most effective and widely-used medications for lowering cholesterol. These drugs—which include lovastatin (Mevacor), pravastatin (Pravachol), and atorvastatin (Lipitor)—not only improve cholesterol levels (primarily by lowering LDL), but may also have a beneficial effect directly on artery walls themselves. (Some recent studies have suggested that statins may have other health benefits, such as lowering the the risk of stroke in people with heart disease—but more research is needed to confirm this.)
Not A Clear-Cut Decision
No one should elect to take any type of drug to lower cholesterol without first consulting his or her doctor. Some people experience side effects such as muscle pain and/or weakness and liver damage. And no one knows how safe these drugs are over a lifetime, though they appear to be quite safe. Therefore, the decision to take a drug should be made in light of an overall evaluation of a person’s risk for heart disease.
You will need advice from your doctor, and you will also need a fasting test to obtain a cholesterol profile of your HDL and LDL. Your doctor will also need to check for adverse reactions to any drug you start taking, regulate dosages, and judge the effects of medication on your cholesterol levels.
Some Cholesterol Guidelines
- You probably don’t need a statin drug if your LDL cholesterol is 130 or lower, your HDL is at least 40, and you have good health habits and few, if any, coronary risk factors.
- You may want to discuss statin drugs with your doctor if your LDL is above 130, your HDL is below 40, and you have any other risk factors for heart disease: you smoke, have high blood pressure, are sedentary, overweight, have diabetes, eat a lot of foods high in saturated fat, or are a man over 45 or a woman over 55. Also be sure to ask your doctor about possible interactions between statins and any other medication you are taking.
- You may want to discuss taking low-dose aspirin. Depending on your risk factor profile, a daily low-dose aspirin may be a more appropriate, and much less expensive, measure to reduce your risk of a heart attack. But don’t start taking aspirin without talking to your doctor.
- If you’re a woman at or past menopause, you might consider starting hormone replacement therapy. The hormone estrogen tends to raise HDL. But there are a number of factors to weigh in deciding whether to take hormones, and you’ll need to discuss these with your doctor.
Remember that there is no substitute for a healthy lifestyle if you want to reduce your risk of heart disease. The heart-healthy habits outlined under “Home Remedies” and on pages 64-65 are always something to try before taking drugs—and while taking drugs.
Home Remedies for Cholesterol
The following measures tend to lower total cholesterol and LDL levels, and also tend to raise HDL levels—or may at least stabilize HDL while bringing down LDL. (Not everyone responds to these changes, and if your total cholesterol level remains high after several months of adopting these changes, you should consult your doctor about taking cholesterol-lowering drugs, as explained on page 203.
- Lose weight. Not only does excess body fat raise LDL levels and reduce HDL, but it also appears to be an independent risk factor for heart disease. Where the fat accumulates is also important: excess weight around the waist (the so-called apple-shape body) seems to reduce HDL more than weight in the hips and thighs (pear shape).
- Cut down on saturated fats. This is the most important dietary step you can take. First, keep your total fat intake at or below 30 percent of your daily calories. Secondly, substitute unsaturated fats for saturated fats. Studies have shown that polyunsaturated fats (such as safflower and corn oil) and monounsaturated fats (such as olive oil) help to lower blood cholesterol levels. Monounsaturated fats may help maintain or increase the level of HDL cholesterol as well.
- Cut down on dietary cholesterol. It’s estimated that reducing cholesterol intake from food from 500 to 250 milligrams a day will lower total blood cholesterol by an average of 10 milligrams. This response is variable, however; some people have little or no response, and others a far greater one.
- Watch out for “trans fats.” Manufacturers hydrogenate—that is, add hydrogen to—corn, soybean, and other liquid vegetable oils to make them more stable. This prolongs the shelf life of margarines, crackers, cookies, potato chips, and other foods that contain the semisolid oils. Hydrogenated oils are also often used for deep-frying in fast-food restaurants. But hydrogenation alters many of the oils’ unsaturated fatty acids, making them more saturated and changing their structure in other ways that transforms them into trans fatty acids, or simply trans fats. Studies have shown that trans fats act like saturated fats—raising total and LDL cholesterol levels—and there is some evidence that they lower HDL cholesterol as well. Nutrition labels have not specified how much trans fat is in the foods, and it’s not counted as saturated fat. Hence, trans fats have remained invisible on food labels. The Food and Drug Administration (FDA) has recommended that the amount of trans fatty acids in foods be included in nutrition labels (a final ruling on the proposal is expected in 2001). In the meantime, if you eat lots of margarine and also many processed foods, cut back, or switch to a tub or liquid “squeeze” margarine, which has fewer trans fatty acids. “Diet” margarines are even better—they contain more water and only half the fat of other margarines.
- Exercise more. Results of studies have been inconsistent concerning the effect of aerobic exercise or strength-training exercise on total cholesterol and LDL. But the evidence is stronger that an exercise program can help raise HDL, and its effect on lowering the risk of coronary artery disease (CAD) is overwhelming. The exercise doesn’t have to be strenuous—walking a mile or two or even gardening several times a week can help.
- Combine diet and exercise for better results. In a study at the Stanford School of Medicine, a group of subjects who followed both a low-fat diet and a moderate exercise program (equivalent to briskly walking for three hours a week) had an average drop of about 18 points in total cholesterol, while subjects who followed only a dietary or exercise regimen experienced just a small improvement not considered significant.
- Consume more soluble fiber. Eat more legumes, oats, fruits, and vegetables such as carrots, split peas, and corn. Sweet potatoes, zucchini, and broccoli have some soluble fiber, as do bananas, apples, pears, and oranges. If you regularly eat a high-fiber, low-fat diet that includes a variety of the these vegetables and fruits and some oatmeal or oat bran daily, you may see results the next time you have a cholesterol test—particularly if the level was previously elevated.
- Eat fish instead of meat. According to some studies, the oil in fish—polyunsaturated fatty acids called omega-3s—can lower elevated cholesterol. Evidence from other studies disputes this, but substituting some fish for meat (or other sources of saturated fat) should help lower blood cholesterol. Eating fish is preferable to taking fish oil supplements. Not only is fish one of the best nutrient-rich foods around, but it is unclear whether omega-3s, by themselves in supplements, provide the same health benefits as eating the fish itself.
- Consider a drink or two a day. A number of studies have shown that moderate alcohol consumption—defined as no more than two drinks a day for a man, one drink a day for a woman—may boost HDL. The health risks of heavier drinking, however, outweigh the potential benefit for the heart.
- Don’t smoke. Smoking increases total cholesterol and reduces HDL. In addition, it is an independent risk factor for heart disease.
- Drink green tea. It can help lower the level of LDL.
What About “Natural” Remedies?
Several products marketed as dietary supplements claim to help lower blood cholesterol. Some may do just that—but read on before you try them.
There are varying degrees of evidence that three such supplements—guggulipid, niacin, and red yeast rice (sold under the brand name “Cholestin”)—can effectively (and inexpensively) reduce cholesterol levels.
However, if your cholesterol is high, you first need to talk to your doctor, who will consider all of your risk factors for heart disease in arriving at a treatment plan, which may include a prescription drug. Actually, though niacin and Cholestin can be obtained without a prescription, both act as drugs and should not be taken without medical advice and supervision, since dosages must be individually designed.
The dosage for guggulipid is difficult to determine, since there is no guarantee that what you are buying standardized. If you decide to try it, be sure to tell your doctor.
Garlic is also widely advertised as having cholesterol-lowering properties. Here the claims are doubtful. Two recent well-designed studies—one appearing in the Archives of Internal Medicine, the other in the Journal of the American Medical Association—found that garlic had no effect on cholesterol levels. Both studies, which lasted 12 weeks, involved people with elevated cholesterol levels and compared results of garlic against a placebo, or dummy pill.
Interestingly, the studies used two entirely different types of garlic supplement—a garlic oil preparation and a popular garlic powder tablet—yet neither had any cholesterol-lower-
Prevention
The same measures that help lower high cholesterol levels can also help prevent cholesterol levels from rising in the first place, so follow the recommendations described above. You should also have your blood cholesterol level tested periodically by your doctor.
Beyond Home Remedies: When To Call Your Doctor
If you are over the age of 20, consult your doctor about having your cholesterol levels measured. Children who have a family history of heart disease or of high cholesterol levels should also be tested. You can also call your local hospital, health department, or American Heart Association chapter for advice.
Don’t rely on home cholesterol tests. When your doctor does the test, it should be part of an overall evaluation of your risk of heart disease. Also, home tests cannot measure HDL levels.
What Your Doctor Will Do
Blood will be drawn for the test, and beforehand your doctor should give you instructions that will help to ensure the best possible result. These may include not eating anything for 12 hours before the test (if you are having your LDL and triglyceride levels measured); not exercising before your test (which can cause a temporary rise in cholesterol levels for up to an hour after the activity); and sitting down for at least five minutes before your blood is taken. At least two weeks should have elapsed since any surgery, trauma, illness, or physical strain, since these factors can also affect the test results.
Your doctor may want you to have at least two tests performed, separated by a month or two, since cholesterol levels fluctuate.
Your doctor will discuss the results of your test with you. If your cholesterol is high or your HDL is low, the two of you will discuss measures to take—including the possibility of using cholesterol-lowering drugs—to try and bring your cholesterol levels into a desirable range.
Source:
The Complete Home Wellness Handbook
John Edward Swartzberg, M.D., F.A.C.P., Sheldon Margen, M.D., and the editors of the UC Berkeley Wellness Letter
Updated by Remedy Health Media
