Smokers as a group have been found to have poorer dietary habits than nonsmokers, consuming more fat, fewer fruits and vegetables, and only three-quarters of the RDA for vitamin C. The depletion of antioxidants by cigarette smoke, combined with a poor diet, have made it difficult to distinguish between the effects of diet and smoking on antioxidant status in smokers. However, using a study design which matched smokers and nonsmokers in their dietary habits, Lykkesfeldt et al. in a study published in The American Journal of Clinical Nutrition found that supplementation with vitamin C produced significant benefits for the ascorbate-depleted smokers.

Volunteers for this study were healthy 20-50 year old male smokers and nonsmokers from the San Francisco Bay area, specifically chosen because they had a poor diet with – 3 servings of fruits and vegetables per day. Baseline blood samples were taken, and half of the group was provided with a vitamin supplement over the 90 days of the study; the other half received a placebo. The authors looked at a number of different antioxidants, including vitamin C and several different forms of vitamin E, and concluded that vitamin C was the only antioxidant that was significantly affected by smoking. The depletion of ascorbic acid was not due to dietary differences between the groups studied. Smokers showed a much more substantial 3-fold increase in vitamin C levels after supplementation than nonsmokers or subjects in the placebo group.

The authors suggest that smokers benefit more from vitamin C supplementation than nonsmokers because vitamin C is significantly depleted by smoking.

Lykkesfeldt, J et al. Ascorbate is depleted by smoking and repleted by moderate supplementation: a study in male smokers and nonsmokers with matched dietary antioxidant intakes. Am J Clin Nutr 2000;71:530-6.

For more information contact: Dr. Bruce Ames at [email protected]

This media release is provided by The American Society for Clinical Nutrition, to provide current information on nutrition-related research. This information should not be construed as medical advice. If you have a medical concern, consult your doctor.