Cancer Research Lab

High intakes of vitamin A, retinol, and provitamin A carotenoids reduce the risk of gastric cancer, results of a study published in the February issue of the American Journal of Clinical Nutrition suggest.

“Vitamin A may influence gastric carcinogenesis through its essential role in controlling cell proliferation and differentiation,” Dr. Susanna C. Larsson, of Karolinska Institutet, Stockholm, Sweden, and colleagues write. “However, epidemiologic studies of vitamin A, retinol (preformed vitamin A), and provitamin A carotenoids in relation to the risk of gastric cancer have documented inconsistent results.”

In a prospective population-based cohort study of Swedish adults, the researchers examined records of 82,002 Swedish adults who had completed a food-frequency questionnaire in 1997. The subjects were followed through June 2005. Computerized record linkage of the study population to the national and regional Swedish cancer registries was used to ascertain incident cases of gastric cancer.

The mean follow-up was 7.2 years. During that time, a total of 139 incident cases of gastric cancer were diagnosed. The subjects had a mean age at baseline of 61.0 years. Significant inverse associations were observed between intakes of dietary and total vitamin A and retinol and the risk of gastric cancer. A significantly lower risk of gastric cancer was also observed with high intakes of alpha-carotene and beta-carotene.

The multivariate relative risks of gastric cancer comparing the highest with the lowest quartile of intake were 0.53 for total vitamin A (p = 0.02) and 0.56 for total retinol (p = 0.05). The multivariate relative risks for the highest versus the lowest quartiles of intake for alpha-carotene and beta-carotene were 0.50 (p = 0.03) and 0.55 (p = 0.07), respectively. There were no significant associations between beta-cryptoxanthin, lutein, and zeaxanthin, or lycopene intake and gastric cancer risk.

“Significant interactions were found between smoking status and intakes of dietary vitamin A (p = 0.01), total vitamin A (p = 0.01), and alpha-carotene (p = 0.01),” Dr. Larsson and colleagues write. “The associations between vitamin A, retinol, or carotenoid intake and the risk of gastric cancer did not differ significantly across strata of alcohol consumption.”

The results, the authors conclude, “support the hypothesis of a possible protective role of vitamin A in gastric carcinogenesis.”