A comparison of carotenoids, retinoids, and tocopherols in the serum and buccal mucosa of chronic cigarette smokers versus nonsmokers.

Abstract

BACKGROUND: Cigarette smoking, a major risk factor for oropharyngeal cancer, is reported to alter oral levels of carotenoids and tocopherols. Such effects may be important because these nutrients, as well as retinoids, are putative chemoprotective agents. OBJECTIVES: To determine whether chronic smoking is associated with altered concentrations of these nutrients in serum and buccal mucosa; to distinguish whether such effects are ascribable to diet; and to determine whether oral concentrations of these nutrients correlate with a putative biomarker of oral cancer risk. METHODS: Serum and buccal mucosal cells (BMC) were analyzed for these nutrients and for BMC micronuclei in smokers (n = 35) and nonsmokers (n = 21). RESULTS: General linear regression with adjustments for dietary intake showed that smokers possess lower serum concentrations of beta- and alpha-carotene, cryptoxanthin, lutein, and zeaxanthin (P </= 0.01) and a significantly higher serum gamma-tocopherol (P = 0.03). In BMCs, smokers had significantly lower concentrations of beta- and alpha-carotene, lycopene, and alpha-tocopherol (P < 0.05) but significantly higher gamma-tocopherol (P < 0.01). Among nonsmokers, many serum carotenoid concentrations correlated with concentrations of the corresponding nutrient in BMCs whereas no such correlations existed among smokers. BMC micronuclei did not correlate with the oral concentration of any micronutrient. CONCLUSIONS: Chronic cigarette smokers have lower concentrations of many dietary antioxidants in serum and BMCs compared with nonsmokers, an effect which is not entirely ascribable to diet. Nevertheless, the lack of concordance between oral concentrations of these nutrients and genetic damage in the BMCs of smokers does not support a protective role for these nutrients in oral carcinogenesis.