With heart disease having worked its way up the list of leading causes of death in the U.S., cholesterol numbers have become an important piece of information. According to the Centers for DIsease Control and Prevention, about one in every six U.S. adults has high total blood cholesterol. Fortunately, there is such a thing as "good" cholesterol--that is, a type of cholesterol that is actually heart-friendly. This cholesterol, simply referred to as HDL, can be affected by your lifestyle and habits, including smoking.
Basics
HDL stands for "high-density lipoprotein." Also known as good cholesterol, it is actually a carrier molecule that binds to cholesterol in your blood vessels and carries it to the liver for elimination. It thus differs from other lipoproteins, which transport cholesterol from the liver to your organs, According to the Harvard Medical School, HDL accounts for 20 to 30 percent of your total blood cholesterol.
Significance
High blood cholesterol's link with heart disease mainly comes from its association with plaque formation. Indeed, excess cholesterol in your bloodstream can lead to the deposition of fatty deposits, or plaque, in your blood vessels. Plaque accumulation, in turn, can interfere with oxygen and blood flow to various organs, including your heart. This, according to the CDC, results from high LDL, or "bad" cholesterol. In contrast, HDL helps protect your heart by scavenging excess cholesterol deposits. However, you need an HDL count of at least 60 milligrams per deciliter of blood, or 60 mg/dL, for heart-protective effects. HDL values below 40 mg/dL are too low and increase your heart disease risk, indicates the Harvard Medical School.
Guidelines
Official guidelines from the National Cholesterol Education Program list smoking among both the risk factors for heart disease and the factors that lower HDL cholesterol. However, the NCEP does specify that 50 percent of the variations in HDL levels result from genetic factors, and the other 50 percent from acquired factors, such as smoking. Thus, if you already have a genetic predisposition to low HDL, smoking could drive your levels to drastically low levels.
Research
It has long been established that smoking introduces toxic substances in your bloodstream. Nicotine, tar and free radicals are only a few examples. In agreement with the clinical practice surveys reported in the NCEP, a number of research studies indicate that smoking does not only accelerate plaque formation in your arteries, it also lowers HDL levels, as indicated in a 2009 issue of the "Journal of Lipid Research." What's more, a 2010 Japanese study featured in "Pediatrics International" revealed that exposure to cigarette smoke adversely affects HDL levels in non-smoking children and adults. The greater the cigarette exposure, the lower the HDL count dips.
Lifestyle Changes
Medical research does not currently indicate that smoking can raise HDL levels. In fact, if you currently smoke, quitting can increase your HDL levels by up to 10 percent, according to the Mayo Clinic. Losing excess weight and exercising regularly can also improve your cholesterol profile. Helpful dietary changes include a diet that is rich in fiber and low in fat, particularly trans fats and saturated fats.
References
- Harvard Medical School: Making sense of cholesterol yests
- Centers for Disease Control and Prevention: Cholesterol
- National Cholesterol Education Program: Detection, Evaluation & Treatment
- "Journal of Lipid Research"; The Effects of ABCG5/G8 Polymorphisms on Plasma HDL Cholesterol Concentrations Depend on Smoking Habit; M. Junyent et al.; March 2009
- "Pediatrics International"; Passive Smoking Is Associated with Lower Serum HDL-C Levels in School Children; K. Hirata, et al. April 2010
