Antioxidant Micronutrients and Biomarkers of Oxidative Stress and Inflammation in Colorectal Adenoma Patients: Results from a Randomized, Controlled Clinical Trial

Previous epidemiologic observational and experimental studies investigated the potential of antioxidant micronutrients to modulate cancer risk, but these studies produced inconsistent results. In this pilot, randomized, double-blind, placebo-controlled clinical trial ( n = 47), we assessed the effects of an antioxidant micronutrient combination (800 mg dl-α-tocopherol acetate, 24 mg β-carotene, 1.0 g vitamin C, 200 μg l-selenomethionine, 7.2 mg riboflavin, 80 mg niacin, 60 mg zinc, 5 mg manganese) given daily over 4 months on oxidative and inflammatory biomarkers in patients with a history of sporadic colorectal adenoma. Plasma tumor necrosis factor-α (TNF-α), interleukin-6, and F2-isoprostane concentrations were measured using ELISAs, and cystine (CySS) was measured using high-performance liquid chromatography. Plasma TNF-α concentration decreased in the active treatment group by 37% relative to the placebo group ( P = 0.002), and CySS decreased by 19% ( P = 0.03); however, interleukin-6 and F2-isoprostane concentrations decreased in antioxidant-treated nonsmokers but increased in smokers, although these findings were not statistically significant. The decreases of TNF-α and CySS were more pronounced in nonsmokers. These data suggest that ( a ) an antioxidant micronutrient cocktail can modulate biomarkers of oxidative stress and inflammation in humans and ( b ) the effects of antioxidant micronutrient supplementation on biomarkers of inflammation and oxidative stress may differ according to smoking status. Cancer Epidemiol Biomarkers Prev; 19(3); 850–8