Vitamin E may prevent smoking damage to arteries
NEW YORK, Feb 01 (Reuters Health) -- Taking vitamin E supplements may help protect the cells that line arteries from damage immediately after cigarette smoking, but do not appear to reverse the long-term arterial damage caused by smoking, Austrian researc
In a study published in the Journal of the American College of Cardiology, physicians at the University of Vienna and the University of Innsbruck, Austria, examined the short-term effects of vitamin E supplements on 22 healthy male smokers.
Prior studies have shown that cigarette smoking promotes the formation of molecules called ``free radicals'' in the bloodstream. These free radicals are highly reactive chemicals that cause oxidation, or changes that alter the cell lining of the arterial walls (the endothelium). Vitamin E can counter these changes because it is an antioxidant, meaning that it can absorb or neutralize damage-causing free radicals.
``Free radicals have been implicated in several chronic diseases such as cancer or arthritis. They can cause terrible harm to the body, and not only to the endothelium,'' said Dr. Jerome D. Cohen, professor of medicine in cardiology at Saint Louis University School of Medicine, Missouri, in an interview with Reuters Health.
According to Cohen, ``The chemicals in cigarette smoke lessen and can reverse the ability of the arterial walls to dilate during periods of stress or exercise, when increased blood flow is necessary. In fact, cigarette smoking may even cause the arterial walls to constrict. This may account for the increased incidence of sudden death and heart attacks seen in smokers.''
Study participants, who smoked from 14 to 32 cigarettes per day, were assigned randomly to one of two groups. For 4 weeks, one group received 600 IU of vitamin E per day; the other group received a placebo, or ``dummy'' pill. Eleven age-matched healthy male nonsmokers were also included in the study for comparison purposes.
The investigators used ultrasound scans to measure endothelial function in the arm arteries of study participants at the beginning of the study, and again after 4 weeks. They took measurements 2 hours after the men smoked a cigarette, and again 20 minutes after smoking a cigarette.
Results indicated a more marked decline in endothelial functioning after cigarette smoking in those who took placebo rather than vitamin E, suggesting that the antioxidant had helped prevent impaired endothelial function. However, no long-term improvement in endothelial dysfunction was noted after 4 weeks of vitamin E supplementation.
``This study demonstrates that oral vitamin E supplementation can attenuate the transient impairment of endothelial function after heavy smoking due to an improvement of the antioxidant status, but cannot restore chronic endothelial dysfunction within 4 weeks,'' the Austrian research team concludes.
Cohen noted, ``Taking vitamin E supplements is no substitute for smoking cessation, and it does not produce the reduction in the incidence of heart attack or stroke that we would like to see. The only way to prevent the harm that smoking causes is to quit.'' SOURCE: Journal of the American College of Cardiology 2000;35:277-283.