Vitamin E May Protect LDL Cholesterol from Changes that Lead to Heart Disease
BACKGROUND: The low-density lipoprotein (LDL) form of cholesterol is considered the "bad" form of cholesterol because it is strongly associated with an increased risk of developing coronary heart disease. However, considerable research indicates that LDL cholesterol promotes heart disease only when it becomes oxidized, or damaged by free radicals. Vitamin E is known to quench free radicals.
RESEARCH: Researchers analyzed vitamin E levels in the LDL cholesterol of 27 smoking and 62 nonsmoking men and women, mostly in their 50s. They also investigated differences in susceptibility of LDL to oxidation between the smokers and nonsmokers.
RESULTS: Nonsmokers had higher levels of vitamin E in their LDL cholesterol, suggesting a reduced risk of LDL oxidation. In experiments using the subjects' blood, nonsmokers were more resistant to LDL oxidation while smokers were more susceptible to LDL oxidation.
IMPLICATIONS: Heart disease and other cardiovascular diseases are the leading causes of premature death in industrialized nations. Smoking raises the risk of these diseases. In this study, researchers found that smoking promoted the oxidation of both vitamin E and LDL, thereby increasing requirements for vitamin E. The researchers concluded: "For smokers, the presence of alpha-tocopherol (vitamin E) in LDL effectively protects LDL from oxidation."
Liu CS, Chiang TH, Kuo CL, et al. Alpha-tocopherol is important to inhibit low-density lipoprotein oxidation in smokers. Nutrition Research 2004; 24:361-371 VERIS Research Information Service. Research Alert of September 2004