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Cholesterol

Cholesterol: the Good, the Bad, and the Ugly

By Julia Blank, MD

You've heard talk around the office water-cooler:  total cholesterol is passe, it's the LDL that matters.  Or is it the HDL?  Or the Lp(a)?  No-wait!-it's the CRP, that's it!

How do you make sense of this alphabet soup, and what does it all mean for your health?

Cholesterol Basics

Cholesterol is a fat-like substance that has many roles in the body.  It forms an essential component of all of the body's cell membranes, and is a building block of various hormones such as testosterone and estrogen.  It also circulates in the bloodstream, "piggy-backing" on proteins called lipoproteins.  These complexes are categorized according to size and density, which in turn determines whether the effect on the body is beneficial or harmful.  For example, low-density-lipoprotein (aka LDL, or "bad cholesterol") can accumulate along the inner walls of arteries, forming artery-clogging "plaques" that increase your risk of having a heart attack or stroke. High-density-lipoprotein (HDL, or "good cholesterol"), on the other hand, scavenges for cholesterol to take out of circulation and return to the liver, thereby reducing your risk of heart attack or stroke.

Cholesterol comes from two sources.  Foods such as eggs, butter, and red meat contain both cholesterol and saturated fat, which is converted by the body into cholesterol.  We also make cholesterol de novo in the liver-in fact, the liver produces all the cholesterol that we need.

When you get your cholesterol checked at the doctor's office, you usually get a "lipid profile" drawn that includes total cholesterol, LDL, HDL, and triglycerides.  Triglycerides are a form of fat stored in the body's fat cells; triglycerides also circulate in the blood.  High levels can come from a high carbohydrate intake (especially simple sugars, like those found in sweets, soda, and white bread/rice products), or as a result of other conditions such as diabetes.   Like people who have high LDL, those with elevated triglycerides can be at higher risk for cardiovascular disease.

Cholesterol and Your Health: The Big Picture

High cholesterol-or, more precisely, high LDL-is a risk factor for cardiovascular disease.  The higher the LDL and the lower the HDL, the greater the chance of having a heart attack or stroke.  This does not mean that people whose cholesterol is "normal" (see "Cholesterol levels & what they mean" below) are completely in the clear.  Some people with healthy cholesterol levels may have other risk factors.

The good news is that you can do something to reduce many of these risk factors, including:

Cigarette smoking - you can cut your risk of developing heart disease in half if you quit smoking.  However, it may take as long as 5 to 15 years to return to the lower risk level of someone who never smoked.

High blood pressure - while some people may be genetically predisposed to having high blood pressure (for example, if you have a parent or sibling with high blood pressure), many people can lower their blood pressure by watching their diet, exercising, and losing weight.

Diabetes - this is a risk factor that has recently been recognized as a "heart disease equivalent"; in other words, people with diabetes have as high a risk of having a heart attack or stroke as someone who has already suffered a previous heart attack or stroke.  If you already have diabetes, you should keep your blood sugar under good control and follow up with your physician regularly to monitor your cholesterol, blood pressure, kidney function, eye and foot health.  If you don't have diabetes, you can lower your risk of developing it by watching your diet and exercising.

Obesity or Overweight - excess weight can be associated with higher LDL levels, elevated triglycerides, high blood pressure, and increased risk of diabetes.  Losing weight-even as little as 10% of your body weight (e.g. 20 pounds in someone who weighs 200 pounds)-can help to reduce your risk of developing these conditions.  If you already have any of these conditions, losing weight can help improve your control of your condition or slow down its progression.

Unfortunately, there are some risk factors that you can't do anything about.  For example, you can't change your genes, and you can't turn back time.  The non-modifiable risk factors are:

  • Family history of early heart disease (heart attack or stroke in a father or brother before age 55, or in a mother or sister before age 65)
  • Age - men 45 years old or more, women 55 and over
     

There are also markers of increased risk that we are still learning about.  These include:

Homocysteine - this is an amino acid that circulates in the blood.  High levels of homocysteine have been linked to higher risk of heart disease, even in the presence of normal cholesterol levels.  Lowering homocysteine levels by taking folate supplements (B12 and B6 supplements can further lower homocysteine levels) has been shown to decrease cardiovascular risk.

Lp(a) - this is a type of lipoprotein that has been shown to be an independent risk factor in predicting vascular disease and stroke.   While it is not typically measured when screening for high cholesterol, it can be a useful tool in deciding how aggressively to treat a borderline-high cholesterol.  Niacin can lead to modest reductions of Lp(a) levels, but if you have both a high LDL and a high Lp(a), you get a much bigger reduction of cardiovascular risk by treating the high LDL aggressively.

C-reactive protein (CRP) - this is a marker of inflammation that was also shown to be an independent risk factor for heart disease and stroke.  Like Lp(a), CRP can help to guide treatment of cholesterol.  The jury is still out regarding whether lowering CRP levels per se (e.g. by taking anti-inflammatory medications or cholesterol-lowering "statins") will improve your cardiovascular risk profile. 

Cholesterol Levels and What They Mean

While there is no "normal" cholesterol level, there are desirable goals that depend on your individual risk profile.  Keeping your cholesterol under these limits will help to lower your cardiovascular risk.

The following guidelines were issued in the Third Report of the Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III, or "ATPIII"):

  • If you're twenty years old or over, get your fasting lipid profile checked every five years (fasting means no food for 8-12 hours).  You may need it checked more often if any of the results are outside the desirable range.
  • Count up your risk factors (not including LDL):
    • If you already have coronary heart disease (CHD), or a "CHD-equivalent" such as diabetes, carotid artery disease, peripheral artery disease, or an abdominal aortic aneurysm, your risk of having a recurrent heart attack or stroke is greater than 20% over ten years.
    • For everyone else, the 10-year cardiovascular risk depends on the number of risk factors.
    • Each of the following is counted as a major risk factor:  cigarette smoking, high blood pressure (or being on blood pressure medication), family history of early heart disease, age, low HDL (<40 mg/dL).  If you have a high HDL (>60 mg/dL), subtract one risk factor from your total count, since high HDL actually has a protective effect on your heart.  (For a more detailed assessment of your individual risk of developing a heart attack in the next 10 years, see the risk calculator based on data from the Framingham Heart Study.

 

  • Your goal LDL is based on your calculated risk category, as follows:
If your risk category is... Then your goal LDL is...
CHD or CHD equivalent
(10-year risk of having a heart attack > 20%)
<100 mg/dL
2 or more risk factors (not including LDL itself)
(10-year risk of having a heart attack 10-20%)
<130 mg/dL
0 or 1 risk factor
(10-year risk of having a heart attack < 10%)
<160 mg/dL
  • Goal range for HDL is > 40 mg/dL.  Goal for triglycerides is <150 mg/dL. 

How to Improve Your Cholesterol Profile

You've gone through the calculations, and your cholesterol needs improvement.  What now?

The first step is consulting with your doctor about making adjustments to your diet and exercise routine-the so-called "therapeutic lifestyle changes."  These include:

  • Decreasing the amount of saturated fat in your diet, while increasing the relative proportion of unsaturated fat (or "good fat," which can be found in olive oil, nuts, and fatty fish like salmon and tuna).  This helps to reduce LDL cholesterol.
  • Limiting the simple carbohydrates in your diet, while increasing the amount of fiber you eat.  This can help to lower triglycerides.  (See sample cholesterol-lowering diets.)
  • Adding or increasing your physical activity.  This has a positive effect on all cholesterol parameters:  reducing LDL and triglycerides, as well as elevating HDL.   (See exercise suggestions.)
  • In addition to the above, your doctor may also recommend that you take over-the-counter supplements such as fish oil capsules, omega-3 fatty acids, or flaxseed oil, which can help to improved your cholesterol profile.
     

In most cases, after a three- to six-month trial of therapeutic lifestyle changes, you should have your cholesterol rechecked.  If the numbers are now within your goal range, you should continue your current regimen.  If the numbers are still high, your doctor may prescribe a cholesterol-lowering medication.

Medications currently on the market include:

  • Niacin - This is a B vitamin that in high (prescription) doses lowers LDL and triglycerides, and raises HDL.  Minor side effects include itching, headache, and flushing (this last effect can be minimized by either taking the extended-release form of niacin, or by taking a baby aspirin just before you take the niacin).
  • Bile-acid sequestrants - These medications reduce the amount of cholesterol produced by your liver.  Common side effects include constipation, upset stomach, and gas or bloating.
  • Statins (aka HMG-CoA reductase inhibitors) - These medications interrupt the final step in cholesterol production by the liver.  Research has also shown that statins may help to stabilize atherosclerotic plaques in blood vessels, thereby further reducing your risk of heart attack or stroke.  Common side effects of the statins include headache, abdominal pain, gas, diarrhea, and constipation; more serious but rarer side effects include muscle pain or liver damage.  For this reason, patients taking statins such as Lipitor, Zocor, Mevacor, and Pravachol need to have regular blood work to check their liver enzymes.
  • Zetia - this relatively new addition to the cholesterol-lowering armamentarium helps to reduce LDL by reducing absorption of dietary cholesterol from your digestive tract.  It can be used in conjunction with a statin, or on its own in patients who cannot tolerate statin therapy.

If you still have questions about cholesterol, diet, exercise, or cardiovascular risk...

  • Schedule an appointment to discuss your concerns with your doctor. (See SMBP office locations and hours, or meet Our Physicians for your physician's location and telephone number)
  • For information on fitness and exercise, see Shape Up America!
  • For information on heart disease and stroke, see  the American Heart Association website or links to news and information on heart disease.