Handbook of Vitamin C Research

56Yasuo Kagawa, Shizu Higasa, Masaru Tsujimura et al.Results(1) Gene Variant FrequencyThe gene variant frequencies of SNPs (SOD2, SOD3, GSTP1-1, and GSTP1-2) inxenobiotic enzymes among groups A, B and C were as follows:[SNP: total number; genotype: subject number (gene variant frequency in %)]A. Group A : Japanese.SOD2: n = 211; AA, 156 (73.9%); AG, 48 (22.7%); GG, 7 (3.3%).SOD3: n = 209; CC, 192 (91.9%); CG, 17 (8.1%).GSTP1-1: n = 210; AA, 149 (71.0%); GA, 57 (27.0%); GG, 4 (1.9%).GSTP1-2 n = 210; CC, 210 (100%).B. Group B: Japanese, VC depletion-repletion experiment.SOD2: n = 17; AA, 11 (64.7%); AG, 6 (35.3%).SOD3: n = 17; CC, 16 (94.1%); CG, 1(5.9%).GSTP1-1:n = 17; AA, 12 (70.6%); GA, 5 (29.4%).GSTP1-2: n = 17; CC, 17 (100 %).C. Group C: Mongolian (undetermined subjects were excluded)SOD2: n = 94; AA, 55 (58.5%); AG, 32 (34.0%); GG, 7 (7.4%).SOD3: n = 94; CC, 87 (92.6%); CG, 7 (7.4%).GSTP1-1: n = 93; AA, 58 (62.4%); GA, 34 (36.6%); GG, 1 (1.1%).GSTP1-2 n = 94; CC, 94 (100%).Genotype frequencies of GSTP1-1 were consistent with the Hardy-Weinbergequilibrium, as reported for Italians [38] and other ethnic groups [39]. As there was very fewsubject with the CG SOD3 polymorphism, and there were no polymorphic differences inGSTP1-2, the association between VC metabolism and SOD2, as well as GSTP1-1, wasanalyzed. Genotype frequencies of these enzymes among Mongolians were very similar tothose of Japanese.(2) Results of Epidemiological Survey on VC and Oxidative Stress (Table1)When compared with daily food intake of Japanese (values in parenthesis indicatepercentage of Japanese intake), Mongolians consumed few VC sources: 79.5 g of vegetables(25.6%), 32.8 g of fruits (28.0%) and 37.4 g of potatoes (58.0%). According to the survey ofUNICEF Nutrition Status of Population of Mongolia, Second National Nutrition Survey(Ulaanbaatar 2002), average VC consumption was 57.1 mg/day, which is only 48.8 % of thatof Japanese (117 mg/day) [65]. Table 1 shows a comparison of serum concentrations ofantioxidants in Mongolians and Japanese. Serum VC concentrations among Japanese groupA were 1.25 ± 0.25 mg/dL [6], while that in Mongolian group C was only 0.35 ± 0.23 mg/dL[9]. The oxidation products of guanosine present in DNA and after oxidation excreted inurine were very high among Mongolians (8-hydroxydeoxyguranosine 11.0 ± 4.8 ng/mgcreatinine) (Table 1) [9]. As a marker of ROS, the levels of ROM were measured using the d-