- In order to understand how cigarette smoking affects cholesterol levels, it's important to know what cholesterol does in the body. Cholesterol is a naturally occurring substance that's manufactured by the liver. While there are many different types of cholesterol, the two that receive the most attention are the low-density lipoprotein (LDL), or "bad" cholesterol, and the high-density lipoprotein (HDL), or "good" cholesterol.
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LDL cholesterol is a fatty substance made in the liver and aids in food digestion and hormone production. LDL has been labeled the bad type because it delivers cholesterol throughout the body. HDL cholesterol has the reverse effect, by scavenging fat deposits in the body and returning them to the liver. Together, the LDL and HDL levels define your relative risk for contracting heart disease.
The American Heart Association recommends that adults maintain LDL levels below 100 mg/dl. HDL levels should be higher than 40 mg/dl, with a combined value below 200 mg/dl. Certain factors like high-fat diets and cigarette smoking raise LDL levels and lower HDL. Diet and exercise lower LDL and raise HDL. - Cigarette smoke contains hundreds of toxic chemicals. One in particular, called "acrolein," is a vapor produced by many burning plants, including tobacco. Acrolein is absorbed by the lungs from cigarette smoke and increases LDL levels, contributing to heart disease. It also interferes with the way that HDL removes circulating fat in the blood stream and interferes with protein synthesis in LDL. As a result, the immune system targets LDL molecules as "enemies" and releases white blood cells, causing inflammation.
- Almost immediately after quitting smoking, the body responds favorably to smoking cessation. Without acrolein, both the LDL and HDL cholesterol are allowed to return to their "normal" levels -- LDL cholesterol levels decrease and HDL cholesterol levels increase.
