How Smoking Affects Your Cholesterol And Heart
When people think about the long-term effects of smoking, they usually think about lung disease and cancer. However, smoking can also negatively affect other aspects of your health, including your heart health.
When it comes to cholesterol, it doesn’t just go into your stomach, it goes into your lungs. Obviously, diseases such as oral cancer, lung cancer, and emphysema are caused by smoking, but how does smoking lead to high cholesterol and heart disease?
Cigarettes contain a variety of toxins, including acrolein, a particularly reactive chemical. Acrolein is a yellowish, smelly vapor produced when tobacco and other plants are burned. Acrolein is easily absorbed into the bloodstream through the lungs, and scientists believe it can affect cholesterol metabolism and lead to heart disease.
Cholesterol Basics
Cholesterol is a naturally occurring fatty substance in our bodies that is produced by the liver to help produce hormones and digest food. Cholesterol circulates in the blood as two different proteins.
Low-density lipoprotein (LDL), known as the “bad cholesterol,” carries cholesterol around the body, while high-density lipoprotein (HDL), known as the “good cholesterol,” collects fat and sends it back to the liver.
To maintain heart health, the American Heart Association recommends keeping LDL levels below 100 mg/dL, HDL levels above 40 mg/dL, and overall levels below 200 mg/dL.
Eating too much high-fat food can upset this balance, and recent studies have shown that smoking may also upset this balance. Acrolein inhibits HDL’s ability to self-cleanse by attacking proteins. As a result, more fat is stored in the blood and other parts of the body.
Smoking and heart attack risk
The effect of smoking on cholesterol is best known: it lowers levels of high-density lipoprotein (HDL), which is protective against heart disease and is especially beneficial for women, who generally have higher cholesterol levels than men. Because smoking lowers HDL levels, any benefit women may have had when they smoked is wiped out. However, while there are no conclusive studies showing that smoking alters low-density lipoprotein (LDL) levels, smoking exacerbates the harm that LDL naturally does to the body.
This chronic inflammation of the blood vessels and the buildup of fatty plaque is known as atherosclerosis. Plaque restricts blood flow throughout the body. Over years of growth, plaque can rupture and form blood clots, reducing or blocking blood flow to the heart and causing a heart attack. If blood flow to the brain is blocked, the clot can also spread throughout the body and cause a stroke.
How does acrolein in cigarettes affect cholesterol?
Acrolein also inhibits LDL by blocking a protective enzyme that is responsible for keeping LDL intact. Without this enzyme, LDL is susceptible to oxidation, a complex chemical process that changes its molecular structure. This structural change renders LDL unrecognizable to the immune system. In response, the immune system releases white blood cells and other disease-fighting substances that bind to the affected area, leading to inflammation and additional buildup in the affected area.
Genetic susceptibility to heart disease in smokers
Although the toxins that enter the lungs are the same for all smokers, the effects on the body vary from person to person; a 2007 study showed that genetic factors play an important role in the risk of cardiovascular disease in smokers.
Researchers at the University of Rochester have found that 60 to 70 percent of the population has a common genetic defect in a substance that maintains the ratio of HDL to LDL. This substance is called cholesterol transfer protein (CETP). Its exact function is not fully understood, but scientists believe that CETP mediates the conversion of HDL cholesterol to LDL cholesterol.
In the presence of a genetic defect, CETP operates at full capacity, attacking HDL and breaking it down into particles that can be easily removed from the bloodstream. This leads to a decrease in HDL levels.
Since smoking also lowers HDL levels, the study authors noted that the cumulative effect of smoking and the genetic defect significantly increases the risk of heart disease. The study showed that smokers with genetic defects “had a 12-year earlier risk of heart disease than nonsmokers.” Smokers who did not have the 12 common genetic defects had the same risk of heart attack as nonsmokers.
Blocked arteries are the cause of cardiovascular disease
Whatever happens, the buildup of cholesterol in the body is a recipe for cardiovascular disease.
High levels of total cholesterol and LDL cholesterol increase the risk of inflammation and a buildup of white blood cells called plaque (not to be confused with dental plaque). The buildup of arterial plaque remains soft at first. However, over time, it may harden and break down, leading to blood clots13.
The more plaque and clots in the arteries, the harder it is for blood to circulate throughout the body, forcing the heart to work harder to deliver oxygen and nutrients to the body. As clogged arteries (a disease called atherosclerosis) develop, blood flow to certain parts of the body may decrease.
Extreme reductions in blood flow to the heart, known as coronary artery disease, are the leading cause of death in the United States. Stroke is another cause of death, and it is caused by a reduction in blood flow to the brain.
Smoking habits play a role in cholesterol levels and cardiovascular disease risk, but diet and activity levels are also factors. Individuals seeking ways to quit smoking and lower their cholesterol levels should consult with their health care provider.
What can be done to reverse the damage to the heart caused by smoking?
Smoking and high cholesterol are obviously a bad combination, but the good news is that quitting smoking can make a big difference. Quitting smoking can have an immediate effect on cholesterol levels and reduce the risk of a heart attack.
A review of studies published in September 2013 in the journal Biomarker Research found that HDL levels increased by 30 percent just three weeks after quitting.
According to Newby, quitting smoking quickly corrects the negative effects of smoking on blood pressure and blood platelets. In addition, the risk of heart attack is reduced by about 30 percent within the first year of quitting.
