High blood cholesterol

Cholesterol is found in every cell in your body. Cholesterol is used by your body to build healthy cells, as well as some vital hormones.

When you have high cholesterol, you may develop fatty deposits in your blood vessels. Eventually, these deposits make it difficult for enough blood to flow through your arteries. Your heart may not get as much oxygen-rich blood as it needs, which increases the risk of a heart attack. Decreased blood flow to your brain can cause a stroke.

High cholesterol (hypercholesterolemia) is largely preventable and treatable. A healthy diet, regular exercise and sometimes medication can go a long way toward reducing high cholesterol.

High cholesterol has no symptoms. A blood test is the only way to detect high cholesterol.

Ask your doctor for a baseline cholesterol test at age 20 and then have your cholesterol retested at least every five years. If your test results aren’t within desirable ranges, your doctor may recommend more frequent measurements. Your doctor may also suggest you have more frequent tests if you have a family history of high cholesterol or other risk factors, like smoking or diabetes.

Cholesterol is carried through your blood, attached to proteins. This combination of proteins and cholesterol is called a lipoprotein. You may have heard of three different types of cholesterol, based on what type of cholesterol the lipoprotein carries. They are:

  • Low-density lipoprotein (LDL). LDL, or “bad,” cholesterol transports cholesterol particles throughout your body. LDL cholesterol builds up in the walls of your arteries, making them hard and narrow.
  • Very-low-density lipoprotein (VLDL). This type of lipoprotein contains the most triglycerides, a type of fat, attached to the proteins in your blood. Like LDL cholesterol, VLDL cholesterol makes LDL cholesterol particles larger, causing your blood vessels to narrow. If you’re taking cholesterol-lowering medication but have a high VLDL level, you may need additional medication to lower it because VLDL is high in triglycerides.
  • High-density lipoprotein (HDL). HDL, or “good,” cholesterol picks up excess cholesterol and takes it back to your liver.

Various factors within your control — such as inactivity, obesity and an unhealthy diet — contribute to high LDL cholesterol and low HDL cholesterol. Factors beyond your control may play a role, too. For example, your genetic makeup may keep cells from removing LDL cholesterol from your blood efficiently or cause your liver to produce too much cholesterol.

You’re more likely to have high cholesterol that can lead to heart disease if you have any of these risk factors:

  • Smoking. Cigarette smoking damages the walls of your blood vessels, making them likely to accumulate fatty deposits. Smoking may also lower your level of HDL, or “good,” cholesterol.
  • Obesity. Having a body mass index (BMI) of 30 or greater puts you at risk of high cholesterol.
  • Poor diet. Foods that are high in cholesterol, such as red meat and full-fat dairy products, will increase your total cholesterol. Eating saturated fat, found in animal products, and trans fats, found in some commercially baked cookies and crackers, also can raise your numbers.
  • Lack of exercise. Exercise helps boost your body’s HDL “good” cholesterol while lowering your LDL “bad”cholesterol. Not getting enough exercise puts you at risk of high cholesterol.
  • High blood pressure. Increased pressure on your artery walls damages your arteries, which can speed the accumulation of fatty deposits.
  • Diabetes. High blood sugar contributes to higher LDL cholesterol and lower HDL cholesterol. High blood sugar also damages the lining of your arteries.
  • Family history of heart disease. If a parent or sibling developed heart disease before age 55, high cholesterol levels place you at a greater than average risk of developing heart disease.

A blood test to check cholesterol levels — called a lipid panel or lipid profile — typically reports:

  • Total cholesterol
  • LDL cholesterol
  • HDL cholesterol
  • Triglycerides — a type of fat in the blood

For the most accurate measurements, don’t eat or drink anything (other than water) for nine to 12 hours before the blood sample is taken.

Interpreting the numbers
Cholesterol levels are measured in milligrams (mg) of cholesterol per deciliter (dL) of blood in the United States and some other countries. Canada and most European countries measure cholesterol in millimoles (mmol) per liter (L) of blood. Consider these general guidelines when you get your lipid panel (cholesterol test) results back to see if your cholesterol falls in optimal levels.

Total cholesterol
(U.S. and some other countries)
Total cholesterol*
(Canada and most of Europe)
Below 200 mg/dL Below 5.2 mmol/L Desirable
200-239 mg/dL 5.2-6.2 mmol/L Borderline high
240 mg/dL and above Above 6.2 mmol/L High
LDL cholesterol
(U.S. and some other countries)
LDL cholesterol*
(Canada and most of Europe)
Below 70 mg/dL Below 1.8 mmol/L Optimal for people at very high risk of heart disease
Below 100 mg/dL Below 2.6 mmol/L Optimal for people at risk of heart disease
100-129 mg/dL 2.6-3.3 mmol/L Near optimal
130-159 mg/dL 3.4-4.1 mmol/L Borderline high
160-189 mg/dL 4.1-4.9 mmol/L High
190 mg/dL and above Above 4.9 mmol/L Very high
HDL cholesterol
(U.S. and some other countries)
HDL cholesterol*
(Canada and most of Europe)
Below 40 mg/dL (men)
Below 50 mg/dL (women)
Below 1 mmol/L (men)
Below 1.3 mmol/L (women)
Poor
50-59 mg/dL 1.3-1.5 mmol/L Better
60 mg/dL and above Above 1.5 mmol/L Best
Triglycerides
(U.S. and some other countries)
Triglycerides*
(Canada and most of Europe)
Below 150 mg/dL Below 1.7 mmol/L Desirable
150-199 mg/dL 1.7-2.2 mmol/L Borderline high
200-499 mg/dL 2.3-5.6 mmol/L High
500 mg/dL and above Above 5.6 mmol/L Very high

*Canadian and European guidelines differ slightly from U.S. guidelines. These conversions are based on U.S. guidelines.

LDL targets differ
Because LDL cholesterol is associated with heart disease, it’s the main focus of cholesterol-lowering treatment. But it’s not as simple as the chart may appear. Your target LDL number can vary, depending on your underlying risk of heart disease.

Most people should aim for an LDL level below 130 mg/dL (3.4 mmol/L). If you have other risk factors for heart disease, your target LDL may be below 100 mg/dL (2.6 mmol/L). If you’re at very high risk of heart disease, you may need to aim for an LDL level below 70 mg/dL (Below 1.8 mmol/L).

So who’s considered very high risk? You might be if you’ve had a heart attack or if you have diabetes. In addition, two or more of the following risk factors also might place you in the very high risk group:

  • Smoking
  • High blood pressure
  • Low HDL cholesterol
  • Family history of early heart disease
  • Age older than 45 if you’re a man, or older than 55 if you’re a woman

Lifestyle changes such as exercising and eating a healthy diet are the first line of defense against high cholesterol. But, if you’ve made these important lifestyle changes and your total cholesterol — and particularly your LDL cholesterol — remains high, your doctor may recommend medication.

The specific choice of medication or combination of medications depends on various factors, including your individual risk factors, your age, your current health and possible side effects. Common choices include:

  • Statins. Statins — among the most commonly prescribed medications for lowering cholesterol — block a substance your liver needs to make cholesterol. This depletes cholesterol in your liver cells, which causes your liver to remove cholesterol from your blood. Statins may also help your body reabsorb cholesterol from accumulated deposits on your artery walls, potentially reversing coronary artery disease. Choices include atorvastatin (Lipitor), fluvastatin (Lescol), lovastatin (Altoprev, Mevacor), pravastatin (Pravachol), rosuvastatin (Crestor) and simvastatin (Zocor).
  • Bile-acid-binding resins. Your liver uses cholesterol to make bile acids, a substance needed for digestion. The medications cholestyramine (Prevalite, Questran), colesevelam (Welchol) and colestipol (Colestid) lower cholesterol indirectly by binding to bile acids. This prompts your liver to use excess cholesterol to make more bile acids, which reduces the level of cholesterol in your blood.
  • Cholesterol absorption inhibitors. Your small intestine absorbs the cholesterol from your diet and releases it into your bloodstream. The drug ezetimibe (Zetia) helps reduce blood cholesterol by limiting the absorption of dietary cholesterol. Zetia can be used in combination with any of the statin drugs.
  • Combination cholesterol absorption inhibitor and statin. The combination drug ezetimibe-simvastatin (Vytorin) decreases both absorption of dietary cholesterol in your small intestine and production of cholesterol in your liver. You may have heard reports that this combination medication is no more effective than taking simvastatin by itself. But, this small study didn’t find any differences in death, hospitalization or heart attacks between the two medications. If you are on this combination medication, you should continue to take it unless your doctor tells you otherwise.

If you also have high triglycerides, your doctor may prescribe:

  • Fibrates. The medications fenofibrate (Lofibra, TriCor) and gemfibrozil (Lopid) decrease triglycerides by reducing your liver’s production of very-low-density lipoprotein (VLDL) cholesterol and by speeding up the removal of triglycerides from your blood. VLDL cholesterol contains mostly triglycerides.
  • Niacin. Niacin (Niaspan) decreases triglycerides by limiting your liver’s ability to produce LDL and VLDL cholesterol. Various prescription and over-the-counter preparations are available, but prescription niacin is preferred as it has the least side effects. Dietary supplements containing niacin that are available over-the-counter are not effective for lowering triglycerides, and may damage your liver.
  • Combination niacin and statin. If your doctor recommends niacin in addition to a statin, you might want to discuss taking a medication that combines both niacin and a statin, such as Simcor or Advicor. These medications can reduce the number of pills you have to take, although no research studies have yet shown that the combination drugs lower cholesterol more than taking niacin and a statin separately.

Most of these medications are well tolerated, but effectiveness varies from person to person. The common side effects are muscle pains, stomach pain, constipation, nausea and diarrhea. If you decide to take cholesterol medication, your doctor may recommend periodic liver function tests to monitor the medication’s effect on your liver.

Few natural products have been proved to reduce cholesterol, but some might be helpful. With your doctor’s OK, consider these cholesterol-lowering supplements and products:

  • Artichoke
  • Barley
  • Beta-sitosterol (found in oral supplements and some margarines, such as Promise Activ)
  • Blond psyllium (found in seed husk and products such as Metamucil)
  • Garlic
  • Oat bran (found in oatmeal and whole oats)
  • Sitostanol (found in oral supplements and some margarines, such as Benecol)

You may have also heard of another supplement to reduce cholesterol, red yeast rice. The Food and Drug Administration released a warning regarding three brands of red yeast rice because they were found to contain lovastatin, the active ingredient in the drug Mevacor. This can be unsafe, since there’s no way to determine the quantity or quality of the lovastatin in the supplement.

If you choose to take cholesterol-lowering supplements, remember the importance of a healthy lifestyle. If your doctor prescribes medication to reduce your cholesterol, take it as directed. Make sure your doctor knows which supplements you’re taking as well.