HDL cholesterol: the "good" cholesterol

Good cholesterol, bad cholesterol: what makes the difference? Is there a "naughty and nice" list for cholesterol?

HDL (high-density lipoprotein) cholesterol is the well-behaved ‘good’ cholesterol. This friendly scavenger cruises the bloodstream. As it does this, it removes harmful bad cholesterol from where it doesn't belong. High HDL levels reduce the risk for heart disease - but low levels increase the risk.

What makes HDL cholesterol, or good cholesterol, good?

HDL is short for high-density lipoprotein. Each bit of HDL cholesterol is a microscopic blob that consists of a rim of lipoprotein surrounding a cholesterol centre. The HDL cholesterol particle is dense compared to other types of cholesterol particles, so it's called high-density.

Cholesterol isn't completely bad. In fact cholesterol is an essential fat. It provides stability in every cell of your body.

To travel through the bloodstream cholesterol has to be transported by helper molecules called lipoproteins. Each lipoprotein has its own preferences for cholesterol, and each acts differently with the cholesterol it carries.

Experts believe HDL cholesterol may act in a variety of helpful ways that tend to reduce the risk for heart disease:

• HDL cholesterol scavenges and removes ‘bad’ cholesterol. HDL cholesterol can detoxify LDL, making it a less harmful form.
• HDL reduces, reuses and recycles LDL cholesterol by transporting it to the liver where it can be reprocessed.
• HDL cholesterol acts as a maintenance crew for the inner walls of blood vessels (endothelium). Damage to the endothelium is the first step in the process of atherosclerosis, which causes heart attacks and strokes. HDL chemically scrubs the endothelium clean and keeps it healthy.

What are good levels for the good cholesterol HDL?

A cholesterol test or lipid panel tells the level of HDL cholesterol. What do the numbers mean?

• HDL cholesterol greater than 1.5 mmol/L are high. That's good.
• HDL cholesterol less than 1.0mmol/L are low. That's bad.

In general people with high HDL are at lower risk for heart disease. People with low HDL are at higher risk.

What can I do if my HDL cholesterol level is low?

If your HDL is low, you can take several tacks to boost your HDL level and reduce your heart disease risk:

• Exercise. Aerobic exercise for 30 to 60 minutes on most days of the week can help pump up HDL.
• Stop smoking. Tobacco smoke lowers HDL, and stopping can increase HDL levels.
• Keep a healthy weight. Besides improving HDL levels, avoiding obesity reduces risk for heart disease and many other health conditions.

In certain cases your doctor may recommend medication to improve your cholesterol level. Remember that multiple factors besides cholesterol contribute to heart disease. Diabetes, smoking, high blood pressure, obesity and genetics are all important as well.

However many factors contribute to heart disease, so your cholesterol levels alone aren’t enough to indicate your risks. People with normal HDL cholesterol can have heart disease. And people with low HDL levels can have healthy hearts. Overall, though, people who have low HDL cholesterol will have greater risk of developing heart disease than people with high HDL levels.

Experts recommend follow-up cholesterol testing every five years for most people. People with abnormal lipid tests, or who have other risk factors, may need more frequent cholesterol checks. By working to improve the results on your next cholesterol test - or just to keep your numbers looking good - you'll reduce your risk for heart disease.