Positive Health Online

Abstract

ZHANG and colleagues, Department of Infectious Disease and Tropical Medicine, Research Institute International Medical Center of Japan, Tokyo write that Helicobacter pylori infection is a risk factor for gastric cancer and that a high dietary intake of vitamin C appears to protect against gastric cancer, perhaps by scavenging free radicals which may be enhance by H. pylori. Vitamin C has not been studied in relation to any direct action on H. pylori, and the authors attempted to clarify this possibility in vitro and in vivo.

Background

Methodology

H. pylori susceptibility testing of 64 strains was performed by the agar dilution technique and bactericidal actions determined using broth cultivation. The effect of vitamin C upon in vivo H. pylori colonisation was evaluated using the Mongolian gerbil model.

Results

Vitamin C inhibited the growth of 90% of the bacterial strains incubated at pH values of 7.4, 6.0 and 5.5 at concentrations of 2048, 512, and 128 microg/ml (minimum inhibitory concentrations (MICs)) respectively. Broth cultures exposed to MICs of vitamin C showed a 1.57 approx 2.5-log decrease in number of viable bacteria loss of viability was observed in 24 hours at concentrations 8-fold higher than MICs. In an in vivo experiment, H. pylori colonies decreased significantly in animals given vitamin C orally (10 mg/head/day) for 7 days.

Conclusion

: High doses of vitamin C inhibit growth of H. pylori in vitro and in vivo.

References

Zhang HM et al. Vitamin C inhibits the growth of a bacterial risk factor for gastric carcinoma: Helicobacter pylori. Cancer. 80(10): 1897-903 Nov 15 1997.