Increased serum levels of alpha-carotene, beta-carotene, lycopene and vitamin C are linked to reduced gastric cancer risk, according to data from U.S. researchers.

"Data on blood levels of specific carotenoids and vitamins in relation to gastric cancer are scarce. Little is known about the relationship between prediagnostic serum levels of carotenoids other than beta-carotene and risk of gastric cancer especially in non-Western populations.

"Prediagnostic serum concentrations of alpha-carotene, beta-carotene, beta-cryptoxanthin, lycopene, lutein/zeaxanthin, retinol, alpha-tocopherol, gamma-tocopherol and vitamin C were determined on 191 cases and 570 matched controls within a cohort of 18,244 middle-aged or older men in Shanghai, China, with a follow-up of 12 years," wrote J.M. Yuan and colleagues.

The researchers reported, "High serum levels of alpha-carotene, beta-carotene and lycopene were significantly associated with reduced risk of developing gastric cancer (all Ps for trend less than or equal to 0.05); the odds ratios (95% confidence intervals) for the highest versus the lowest quartile of (alpha-carotene, beta-carotene and lycopene were 0.38 (0.13-1.11), 0.54 (0.32-0.89) and 0.55 (0.30-1.00), respectively.

"Increased serum level of vitamin C was significantly associated with reduced risk of gastric cancer among men who neither smoked cigarettes over lifetime nor consumed greater than or equal to three drinks of alcohol per day, the odds ratios (95% confidence intervals) for the second, third and fourth quartile categories were 0.69 (0.28-1.70), 0.36 (0.14-0.94) and 0.39 (0.15-0.98), respectively, compared with the lowest quartile of vitamin C (P for trend = 0.02)," they added.

"There were no statistically significant relationships of serum levels of beta-cryptoxanthin, lutein/zeaxanthin, retinol, alpha-tocopherol and gamma-tocopherol with gastric cancer risk.

"The present study implicates that dietary carotenes, lycopene and vitamin C are potential chemopreventive agents for gastric cancer in humans," concluded Yuan and coauthors.

Yuan and colleagues published their study in Cancer Epidemiology Biomarkers & Prevention (Prediagnostic levels of serum micronutrients in relation to risk of gastric cancer in Shanghai, China. Cancer Epidem Biomarker Prev, 2004;13(11 Part 1):1772-1780).

For additional information, contact J.M. Yuan, University of Southern California, Department Prevention Med, Kenneth Norris Jr. Comprehensive Cancer Center, Keck School of Medicine, MC 9175, 1441 Eastlake Avenue, Los Angeles, CA 90033.