The effect of ascorbic acid supplementation on the nicotine metabolism of smokers

Background. The relationship of serum ascorbic acid (AA) levels and excreti on of nicotine metabolites was determined in 75 men who smoked at least one pack of cigarettes per day. Methods. The subjects were randomly divided into three groups of 25 each wh o received a placebo, 200 mg of supplementation, or 1000 mg of supplementat ion of AA per day for 1 month. Baseline and weekly serum AA levels were det ermined and simultaneous estimates of urinary excretion of nicotine metabol ites as cotinine equivalents (CE), Results. The group mean serum AA levels in the placebo group decreased 13% after 2 weeks; the group mean serum levels of the supplemented groups incre ased significantly after 1 week (P less than or equal to 0.001) and remaine d elevated over 100% per week from baseline throughout the study. There was a progressive increase in urinary CE: excretion in the placebo group. In t he supplemented groups, group mean CE excretion decreased an average of 5% weekly in the 200-mg group and an average of 33% weekly in the 1000-mg grou p, Pearson's correlation between serum AA and urine CE excretion was signif icant (r = -0.7980, P less than or equal to 0.0003). Conclusions. Body levels of AA affect the level of urinary nicotine metabol ites. The results of this study indicate that dietary levels of AA are inve rsely correlated to urinary excretion of nicotine metabolites and may be du e to suppressed: (1) nicotine intake by smokers who smoked fewer cigarettes or inhale less deeply, (2) nicotine metabolism, or (3) both. (C) 1999 Amer ican Health Foundation and Academic Press.