Your Cholesterol Numbers: The Good, the Bad, the Triglycerides

If you want to maintain healthy cholesterol levels, the first step is knowing your numbers and what they actually mean—but at first glance, that can be confusing. A total cholesterol level of 200 mg/dL or higher raises your risk for heart disease. But what about your “good” cholesterol and “bad” cholesterol numbers? And why should you care about your triglycerides?

Cholesterol is a waxy, fat-like substance that circulates in the blood. While a certain amount of it is normal, too much raises the risk of cardiovascular disease.

“Understanding your cholesterol is even more important than it used to be,” says Yale Medicine cardiologist Antonio Giaimo, MD. That’s because high cholesterol is more common than ever, putting 86 million U.S. adults at risk for developing the arterial plaque that can cause heart attacks, strokes, and other cardiovascular conditions.

Some people inherit genes that lead to high cholesterol, but lifestyle also plays a major role. “A lot of it has to do with more people being overweight and having sedentary lifestyles,” Dr. Giaimo says. “It’s a real benefit to have an objective piece of information telling you it’s time to make changes. The sooner you know that your cholesterol is high, the sooner you can take steps to lower it—along with the risk of serious complications.”

Your primary care provider can order a simple blood test called a lipid panel, which measures four key blood fats: high-density lipoprotein (HDL), low-density lipoprotein (LDL), total cholesterol, and triglycerides. These results, combined with your personal risk factors, help identify your risk for heart disease and provide a helpful picture of your cardiac health.

Traditionally, guidelines recommended fasting for 8 to 12 hours before a cholesterol screening test. Today, many people don’t need to fast, unless they previously had high triglycerides or have a personal or family history of high cholesterol or heart disease. Sugary and fatty foods can cause temporary triglyceride spikes, so fasting can ensure accuracy in higher-risk people, Dr. Giaimo says.

Test results are usually available within a few days.

You may see your test results appear in your electronic medical record before you have a chance to speak with your doctor. Don’t worry—these numbers are easier to understand than they may look at first glance. Lipid panel results include measures for three different types of cholesterol and triglycerides, which is not cholesterol, but an essential fat that can cause problems if they are out of balance.

These results are measured in milligrams per deciliter of blood (mg/dL), which shows the concentration of the cholesterol in a specific amount of blood. Adults ages 20 and older should pay attention to the following:

HDL (“good”) cholesterol

HDL is considered “good” because it eliminates excess cholesterol in the body by carrying it from the bloodstream to the liver to be removed from the body.

• Optimal: 60 mg/dL or above
• Borderline: 40-50 mg/dL (men); 50-59 mg/dL (women)
• Low: Under 40 mg/dL (men); under 50 mg/dL (women)

LDL (“bad”) cholesterol

LDL is considered “bad” because it is the most common type of cholesterol that contributes to plaque buildup in the blood vessels. “For most patients, LDL is the most important component of the cholesterol panel,” Dr. Giaimo says. For patients without a history of heart attack or stroke these values can be a guide:

• Optimal: Under 100 mg/dL
• Near optimal: 100-129 mg/dL
• Borderline high: 130-159 mg/dL
• High: 160 mg/dL or above

Total cholesterol

This number represents all the cholesterol in your blood. It includes both HDL and LDL cholesterol. Total cholesterol is also considered a key indicator for heart disease risk.

• Optimal: Under 200 mg/dL
• Borderline high: 200-239 mg/dL
• High: 240 mg/dL or above

Triglycerides

These are fats converted from unused calories for energy. High triglyceride levels can be caused by obesity, diabetes, and metabolic syndrome and signal risk for heart disease, and pancreatitis, notes Dr. Giaimo. Early signs of metabolic syndrome include slightly high triglycerides and low HDL levels:

• Optimal: Under 150 mg/dL
• Borderline high: 150-199 mg/dL
• High: 200-499 mg/dL
• Very high: 500 mg/dL or above

Lipoprotein(a), or Lp(a), is a sticky, genetically inherited form of bad cholesterol that contains LDL. “Over the last decade, we’ve learned that Lp(a) is an independent risk factor for heart disease and stroke,” Dr. Giaimo says.

Because Lp(a) is genetic, people can have high levels even with normal LDL. A typical cholesterol test does not include screening for Lp(a). Ask your doctor if you need the test—especially if you or a close relative has high cholesterol or early onset heart disease or stroke. A screening must be ordered separately from the typical lipid panel and is only required once in a lifetime.

Non-HDL cholesterol is a measurement of all the plaque-causing cholesterols in the blood, including LDL and some other, less common cholesterols like IDL. It can be a better predictor of cardiovascular risk than just depending on the LDL-C measurement alone.

To calculate your non-HDL cholesterol, subtract your HDL from your total cholesterol. Your health care provider may focus on this number if you have high triglycerides, diabetes, overweight or other risk factors that make your chances of having a heart attack higher than normal.

The U.S. Centers for Disease Control and Prevention (CDC) recommends most healthy adults ages 20 and older have their cholesterol checked every four to six years until age 40, at which point they should be screened annually. If you have heart disease, diabetes, or a family history of high cholesterol, or if you take cholesterol-lowering medications, you should follow your doctor’s guidance.

Absolutely. The American Academy of Pediatrics (AAP) recommends screening children and teens for high cholesterol first between the ages of 9 and 11, and again between age 17 and 21. A pediatrician may recommend screening earlier—starting at age 2 in some cases—if a child has close relatives who have had unhealthy cholesterol or heart problems; an unknown medical history; or if they have a condition such as high blood pressure, diabetes, or obesity.

The primary reason to check cholesterol in children is to identify familial hypercholesterolemia (FH), an inherited defect in the body’s recycling of LDL cholesterol, says Dr. Giaimo. “It’s important to identify that genetic cholesterol problem and treat it early,” he says, noting that the condition can be managed with lifestyle changes and medication. FH affects about 1 in 200 adults. Babies born with the condition have high LDL levels at birth that rise over time, putting them at a much higher risk for coronary heart disease later in life.

Childhood obesity is also contributing to high cholesterol unrelated to FH, and studies show that HDL/LDL imbalances in childhood can track into adulthood.

Cholesterol screening results are just one piece of your overall heart health. Others include age, sex, family history, smoking status, diabetes, and high blood pressure. Health care providers may also use the PREVENT equation—a tool from the American Heart Association and American College of Cardiology—to estimate your 10-year and 30-year risk of a heart attack or stroke.

If your cholesterol is high, your doctor may recommend a coronary calcium scan—a type of low-radiation CT scan of the chest—for adults ages 40 to 70. This test detects plaque buildup in the arteries and can help determine whether you’d benefit from taking a statin, a medication to lower cholesterol. “You want a score of zero,” Dr. Giaimo says.

“We have the tools and the medical advice to help people,” he adds. “But first we need to be tracking their numbers.”

Your provider may encourage you to make lifestyle changes and repeat the screening in a few months. You can talk to your doctor about lifestyle changes to lower your risk, including eating a diet that avoids saturated fats and trans fats, getting enough physical activity, and quitting smoking, Dr. Giaimo says.

“Sometimes it takes longer than a few months to normalize your cholesterol, but with detailed nutritional guidance and exercise recommendations, many people are able to lower it significantly,” he notes.

Over time, however, some people may need medication. “The longer you have high cholesterol, the worse it is,” Dr. Giaimo explains. Younger adults may have more time to improve levels, while older adults may already have plaque buildup. “The longer your body is exposed to high levels of cholesterol, the more likely plaque will develop in the arteries—and it can snowball from there,” he says.