“Bad” versus “good” cholesterol

Most people have heard that high cholesterol is bad for heart health, but many people don’t actually realize that there is both “bad” cholesterol and “good” cholesterol.

What is cholesterol?
Cholesterol is a waxy type of fat (lipid), which travels around the body in the blood. It is an essential molecule, as it is required for building cells, producing bile for digestion, and making vitamins and hormones. Cholesterol is produced in adequate quantities in the liver, but can also be obtained from foods from animals (1).

Cholesterol can’t actually travel around the body by itself, and must instead be packaged with lipoproteins to move through the blood. “Bad” and “good” cholesterol refers to how the cholesterol is packaged.

“Bad” LDL Cholesterol
Most cholesterol in the body is carried around the body by low-density lipoproteins (LDL) and is referred to as LDL cholesterol. This is the “bad” cholesterol, as LDL deposits excess cholesterol in blood vessel walls, where it accumulates, leading to hardening of the arteries, atherosclerosis, and blood clots. LDL cholesterol levels are often considered to be the best predictor of the risk of heart disease (2).

Various factors can contribute to elevated LDL cholesterol, including a high intake of saturated fats (from red meat and dairy) and refined sugars, high alcohol consumption, physical inactivity, smoking, and being overweight or obese.

“Good” HDL Cholesterol
“Good” cholesterol refers to cholesterol carried around by high-density lipoproteins (HDL). HDL collects cholesterol from around the body and delivers it to the liver for recycling or excretion. HDL also carries cholesterol to other organs, where it is used to produce hormones. In addition, HDL cholesterol plays a role in protecting and maintaining the inner walls of the blood vessels by repairing damaged sites (2,3).

How can I lower my “bad” cholesterol and increase my “good” cholesterol?
A combination of losing weight, diet, and exercise is beneficial for improving your cholesterol. Specific changes include increasing fiber intake, limiting carbohydrate, alcohol, and fat intake, and choosing healthier unsaturated fats instead of saturated and trans fats. More information about food choices to improve cholesterol levels is available here. Abstaining from smoking and exercising for at least 30 minutes each day is also beneficial (4).

1. What is Cholesterol? American Heart Association. (2020).
2. HDL (Good), LDL (Bad) Cholesterol and Triglycerides. American Heart Association. (2020).
3. Castelli WP, et al. (1977). HDL Cholesterol and other lipids in coronary heart disease. The cooperative lipoprotein phenotyping study. 55 (5), 767–72.
4. LDL and HDL Cholesterol: “Bad” and “Good” Cholesterol. CDC. Reviewed Jan 2020.