Effects of Three-month Oral Supplementation of β-Carotene and Vitamin C on Serum Concentrations of Carotenoids and Vitamins in Middle-aged Subjects: A Pilot Study for a Randomized Controlled Trial to Prevent Gastric Cancer in High-risk Japanese Population

Prior to a randomized controlled trial to prevent gastric cancer by oral supplementation of β-carotene and vitamin C in a high-risk Japanese population, we examined the serum response to threemonth oral supplementation of β-carotene (0, 3, 30 mg/day) and vitamin C (0, 50, 1000 mg/day) by a three-by-three factorial design using 54 subjects (age range=40–69 years). Serum concentrations of carotenoids, α-tocopherol, and ascorbic acid were examined at baseline, and one, two, and threemonth points. Both serum β-carotene and ascorbic acid were significantly higher in high-dose groups than in each placebo group during the supplementation. The serum β-carotene increased gradually (597–830% increase) during the study, whereas the serum ascorbic acid reached nearly a steady-state at the one-month point and remained stable thereafter (88–95% increase). No statistically significant interaction between β-carotene and vitamin C supplementations was observed either for serum β-carotene or for serum ascorbic acid. Among carotenoids and α-tocopherol examined, serum lycopene in the high-dose β-carotene group was significantly higher than in the placebo group at all points. No unfavorable change in carotenoids and α-tocopherol was observed in any group.