The Effects of Certain Vitamins and Natural Anti‐oxidants on Ornithine Decarboxylase Activity and on Atrophic and Premalignant Changes in the Human Gastric Mucosa

Abstract

The effects of beta‐carotene, vitamin E and a pharmaceutical complex of natural anti‐oxidants (OXY‐GARD) on abnormally high ornithine decarboxylase (ODC) activity in antral gastric mucosa of patients with atrophic gastritis (AG), accompanied by intestinal metaplasia (IM), were studied in a randomized placebo‐controlled clinical trial. In cases with H. pylori infection, preliminary eradication of this bacterium was carried out utilizing a standard chemotherapeutic schedule (de nol+metronidazole+oxytetracycline). Efficient eradication of H. pylori resulted in an ODC activity decrease of 16%, on average. It was shown that supplementation with beta‐carotene, at a daily dose of 20 mg, or with vitamin E, at a daily dose of 400 IU, produced decreases in ODC activity of 46% and 44%, respectively, by three months. Daily supplementation with 1 or 2 capsules of OXY‐GARD for three months resulted in ODC activity decreases of 23% and 48%, respectively. Taking into account that abnormally high ODC activity is associated with a high oncogenic potential and plays a specific role in tumor promotion, it is reasonable to suggest that beta‐carotene, vitamin E and OXY‐GARD act in atrophic or premalignant gastric mucosa as anti‐promoters. Preliminary data indicate that prolonged administration of these nutritional supplements, e.g. beta‐carotene for one year, to IM patients produces the maximum decrease in ODC activity at three months. We found that this decrease was accompanied by a delayed partial regression of IM in nine of 18 patients (response rate 50%, 95% confidence interval 26–74%). A study on the effects of long‐term vitamin E or OXY‐GARD supplementation on IM regression is currently in progress. (Dig Endosc 1996 ; 8 : 184–191)

The influence of the dietary intake of vitamin C and vitamin E on the risk of gastric intestinal metaplasia in a cohort of Koreans

“…It is widely believed that antioxidant vitamins in fresh fruits and vegetables are effective in preventing gastric cancer. However, it is uncertain whether intake of antioxidant vitamins is effective in preventing precancerous lesion of gastric cancer (18)(19)(20)(21)(22). Our results correspond to previous reports presenting the protective effect of antioxidant vitamins against precancerous lesions including GIM (18)(19)(20)(21).…”

“…Additionally, double-blind intervention trial compared the regression rate of GIM between high dose of vitamin E supplementation (400 units/day) group and control group (placebo) for 12 months. While vitamin E supplementation group showed the regression in 8 of 14 subjects (57%) on 6 months and 10 of 14 subjects (71%) on 12 months, control group didn't show the regression in 16 subjects (21). However, controversial results have been suggested.…”

“…However, it is uncertain whether intake of antioxidant vitamins is effective in preventing precancerous lesion of gastric cancer (18)(19)(20)(21)(22). Our results correspond to previous reports presenting the protective effect of antioxidant vitamins against precancerous lesions including GIM (18)(19)(20)(21). In a randomized, controlled chemoprevention trial for 976 subjects with non-metaplastic atrophy and/or intestinal metaplasia, researchers examined the influence of vitamin C supplementation (ascorbic acid: 1g twice a day) on gastric precancerous lesions for 72 months follow-up (18).…”

“…Activation of ornithine decarboxylase (ODC) is important in the pathogenesis of GIM. An intervention study found that supplementation of high dose vitamin E decreased the activity of ODC by 53% after 6 months and by 65% after 12 months (21). Antioxidant function of vitamin C and vitamin E suppress the production of free radical and active oxygen species, which have the important role in gastric carcinogenesis (17).…”