Vitamin C and gastric cancer: supplements for some or fruit for all?

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

OBJECTIVES

Studies have suggested that the dietary intake of antioxidant vitamins, such as vitamin C and vitamin E, has a potential role in inhibiting gastric carcinogenesis. The present study investigated the effect of antioxidant vitamins on the incidence of gastric intestinal metaplasia (GIM).

METHODS

This study included 67,657 Koreans free of GIM who periodically underwent health check-ups. Dietary intake was assessed by a semiquantitative food frequency questionnaire based on the Korean National Health and Nutrition Examination Survey. Participants were categorized into 4 groups by quartiles of dietary vitamin C and vitamin E intake. The Cox proportional hazard assumption was used to determine the multivariable hazard ratio (HR) and 95% confidence interval (95% CI) for GIM.

RESULTS

The third and fourth quartiles of vitamin C intake had a lower risk of GIM than the first quartile (multivariable-adjusted HR, 0.95; 95% CI, 0.88 to 1.03 in the second quartile, HR, 0.88; 95% CI, 0.81 to 0.97 in the third quartile, and HR, 0.85; 95% CI, 0.76 to 0.95 in the fourth quartile). Vitamin E intake greater than the second quartile level was significantly associated with a lower risk of GIM than the first quartile (multivariable-adjusted HR, 0.90; 95% CI, 0.82 to 0.97 in the second quartile, HR, 0.90; 95% CI, 0.82 to 0.99 in the third quartile, and HR, 0.83; 95% CI, 0.74 to 0.94 in the fourth quartile). This association was observed only in the subgroup analysis for men.

CONCLUSIONS

Higher dietary intake of vitamin C and vitamin E was associated with a lower risk of GIM.

Effects of alpha tocopherol and ascorbic acid on Helicobacter pylori colonization and the severity of gastric inflammation

BACKGROUND AND AIM

We aimed to evaluate the changes in histopathologic features, concentrations of vitamins C and E in gastric mucosa, and total antioxidant capacity of the body after ingestion of ascorbic acid and alpha tocopherol in patients with Helicobacter pylori.

MATERIAL AND METHOD

Patients with H. pylori-positive nonulcer dyspepsia were included in this study. Tissue samples were taken from the lesser and greater curvature in both prepyloric antrum and corpus for histopathologic examination and measurement of vitamins C and E concentrations. Blood samples were obtained for measurement of the total antioxidant capacity of the body. The patients were given vitamin C 500 mg BID and vitamin E 200 IU BID for 4 weeks orally. At the end of the 4th week, the initial procedures were repeated. Histopathologic examination of the tissue samples were carried out by two pathologists.

RESULTS

The mean vitamins C and E concentrations in gastric mucosa at the 4th week were higher than those at the beginning (p = .000 and p = .006, respectively). Mean total antioxidant capacity of the body at the beginning and that at the 4th week were similar (p = .689). H. pylori intensity in the antrum at the beginning was higher than that at the 4th week for both pathologists (p = .007 and p = .039). Neutrophilic activity in the antrum at the beginning was higher than that at the 4th week for both pathologists (p = .000 and p = .025). Neutrophilic activity in the corpus at the beginning was higher than that at the 4th week for pathologist 1 (p = .033), and they were similar for pathologist 2 (p = .763).

CONCLUSION

The findings that H. pylori intensity and neutrophilic activity decrease through increasing gastric ascorbic acid and alpha tocopherol concentrations suggest that supplementation with vitamins C and E increases the eradication rates via impairing the microenvironment created by the bacteria and facilitating the diffusion of antibiotics into gastric mucosa.

Efficacy of vitamins supplementation to therapy on Helicobacter pylori eradication in patients with low antioxidant capacity

BACKGROUND AND OBJECTIVES

It was shown that supplementation of vitamins C and E to therapy increased Helicobacter pylori eradication rate. In the present study, we aimed to evaluate whether supplementation of antioxidant vitamins to therapy increases H. pylori eradication rates in patients with chronic stress and low antioxidant capacity.

METHODS

This study included 120 patients who presented to gastroenterology outpatient clinic with H. pylori-positive nonulcer dyspepsia and low total antioxidant capacity. Patients in group A (n=80) were given lansoprazole (30 mg, BID), amoxicillin (1000 mg, BID), and clarithromycin (500 mg, BID) for 14 days, as well as vitamin C (500 mg, BID) and vitamin E (200 IU, BID) for 30 days. Patients in group B (n=40) were given lansoprazole (30 mg, BID), amoxicillin (1000 mg, BID), and clarithromycin (500 mg, BID) for 14 days.

RESULTS

Total antioxidant capacity were lower than normal levels in all patients. One hundred and fifteen patients (77 in group A, 38 in group B) were analyzed with per protocol analysis. In group A, H. pylori eradication was achieved in 63.8% of the patients included in the intention to treat analysis and in 66.2% of the patients included in the per protocol analysis. In group B, H. pylori eradication was achieved in 42.5% of the patients included in the intention to treat analysis and in 44.7% of the patients included in the per protocol analysis. Eradication rates were significantly higher in group A than in group B (P<0.005).

CONCLUSIONS

Supplementation with vitamins C and E increased H. pylori eradication rate of standard triple therapy.

Supplementing vitamins C and E to standard triple therapy for the eradication of Helicobacter pylori

WHAT IS KNOWN AND OBJECTIVE

Helicobacter pylori eradication rates of currently accepted triple therapy regimens vary between geographic locations and do not exceed 70-80%. Eradication rates are much lower in locations where uncontrolled antibiotic use is common such as Turkey. In the present study, we aimed to test whether supplementing vitamins C and E to standard triple therapy, including a proton pump inhibitor plus amoxicillin plus clarithromycin, increased the H. pylori eradication rate.

METHODS

Two hundred patients infected with H. pylori were randomized into two groups in an open-label trial. In group A, patients (n = 160) were given standard triple therapy, including lansoprazole 30 mg BID plus amoxicillin 1000 mg BID plus clarithromycin 500 mg BID for 14 days, plus vitamin C 500 mg BID plus vitamin E 200 IU BID for 30 days. In group B, patients (n = 40) were given standard triple therapy for 14 days. The success of H. pylori eradication was defined as a negative ¹⁴C-urea breath test result, 4-6 weeks after the completion of therapy. Comaprisons were by both intention-to-treat (ITT) and per-protocol (PP) analysis.

RESULTS AND DISCUSSION

Two hundred patients (137 women, 63 men) were analysed using ITT analysis and 195 patients completed the study. In group A, H. pylori eradication was achieved in 132 of the 160 patients (82·5%) included in ITT analysis and 132 of the 157 patients (84%) included in PP analysis. In group B, H. pylori eradication was achieved in 18 of the 40 patients (45%) included in ITT analysis and 18 of the 38 patients (47·4%) included in PP analysis. Eradication rates were significantly higher in group A than in group B (P < 0·005). Eradication rates were not statistically significant between men and women in both groups.

WHAT IS NEW AND CONCLUSION

Adding vitamins C and E to standard triple therapy increases the eradication rate of H. pylori. Vitamins C and E may increase the eradication rate via increasing the effectiveness of the antibiotics by decreasing oxidative stress in the gastric mucosa and strengthening the immune system.

Oxidative stress in Helicobacter pylori infection: does supplementation with vitamins C and E increase the eradication rate?

AIM

This study aims to assess the antioxidant property of vitamins E and C in Helicobacter pylori infection, and to determine if adding them to standard triple therapy plus bismuth subcitrate increases the H. pylori eradication rate.

METHODS

This study included 160 patients infected with H. pylori, who were randomized into one of two groups. Patients in group A (n = 80) received lansoprazole (30 mg, b.i.d.), amoxicillin (1000 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and bismuth subcitrate (300 mg, q.i.d.) for 14 days, while patients in group B (n = 80) received vitamin C (500 mg, b.i.d.) and vitamin E (200 IU, b.i.d.) for 30 days, in addition to lansoprazole (30 mg, b.i.d.), amoxicillin (1000 mg, b.i.d.), clarithromycin (500 mg, b.i.d.), and bismuth subcitrate (300 mg, q.i.d.) for 14 days. Total antioxidant capacity (TAC) was evaluated with a Randox kit. Success rate was calculated using both intention-to-treat (ITT) and per-protocol (PP) analyses.

RESULTS

One hundred and sixty patients were analyzed using ITT analysis. One hundred and fifty-three patients completed the study. In group A, H. pylori eradication was achieved in 48 (60%) of the 80 patients included in the ITT analysis, and in 48 (64%) of the 75 patients included in the PP analysis. In group B, H. pylori eradication was achieved in 73 (91.25%) of the 80 included in the ITT analysis and in 73 (93.5%) of the 78 patients included in the PP analysis. The eradication rate was significantly higher in group B than in group A (p < .005). TAC was at the lower limit of normal in both groups and the difference between them was not statistically significant (p > .05).

CONCLUSION

In group B, H. pylori eradication rate was 91.25%, which is higher than the ideal 80% eradication rate. The results of the present study show that adding the prescribed doses of vitamins E and C to antimicrobial therapy is effective in eradicating H. pylori infection.

Effects of antioxidant vitamin supplements on Helicobacter pylori-induced gastritis in Mongolian gerbils

BACKGROUND

Epidemiological studies show that high intake of food-bound vitamin C and E reduces the risk of gastric cancer. Whether dietary supplementation with antioxidant micronutrients interferes with Helicobacter pylori infection and associated diseases is unclear. The aim of this study was to investigate if dietary vitamin C or E supplementation influences the progression of gastritis, gastric mucosal nitrosative and oxidative protein damage, gastric mucosal lipid peroxidation, or gastric mucosal oxidative DNA damage in H. pylori-infected Mongolian gerbils.

MATERIALS AND METHODS

Gerbils were divided into four groups: H. pylori-infected animals fed with vitamin C- or vitamin E-supplemented food, and infected and uninfected animals given standard rodent food. Subgroups of animals were killed at different time-points until 52 weeks postinfection. Concentrations of 3-nitrotyrosine and thiobarbituric acid-reactive substances (TBARS) in the gastric mucosa were determined with an immunodot blot and a fluorometric method, respectively. Mucosal concentrations of carbonyl carbons on proteins and 8-hydroxydeoxyguanosine were determined by enzyme-linked immunosorbent assay. Gastritis was scored semiquantitatively.

RESULTS

Vitamin supplements had no effect on the colonization with H. pylori. Vitamin C as well as vitamin E supplements reduced mucosal 3-nitrotyrosine concentrations to normal levels in infected animals. Vitamin E supplements decreased mucosal protein carbonyls and TBARS in short-term gastritis. In addition, vitamin C supplements caused attenuated mucosal oxidative DNA damage and milder mucosal inflammation in short-term gastritis.

CONCLUSION

Vitamin C or vitamin E supplementation leads to some short-term protective effects on H. pylori-induced gastritis in Mongolian gerbils. These effects seem to subside over time when the infection persists.

Eradication of Helicobacter pylori restores glutathione S-transferase activity and glutathione levels in antral mucosa

Glutathione S-transferases (GST) and glutathione peroxidases (GPO) are important in detoxification. GST activity in the mucosa of the gastrointestinal tract is inversely correlated with the development of gastrointestinal cancer. Helicobacter pylori (H. pylori) infection has been associated with gastric cancer. We studied GST activity and the substrate glutathione (GSH) in patients with H. pylori-associated gastritis. GST activity and isoenzyme levels, GPO activity and GSH levels were studied in antral biopsies of 38 H. pylori-positive patients, before and after eradication treatment. In 31 patients in whom H. pylori was successfully eradicated, antral GST enzyme activity before therapy was 532 (465 - 598) nmol / mg protein. min (mean and 95% confidence interval) and that after therapy was 759 (682 - 836) nmol / mg protein. min (P < 0.0001). Correspondingly, levels of GST alpha and GST-P1 were higher after eradication (P < 0.001). GSH concentration significantly increased: 21.2 (16.2 - 26.2) nmol / mg protein before and 27.1 (23.6 - 30.6) nmol / mg protein after therapy (P < 0.05). In 7 patients in whom H. pylori was not eradicated, GST activity was 671 (520 - 823) nmol / mg protein. min and 599 (348 - 850) nmol / mg protein before and after treatment respectively (P = 0.32). GSH levels were 17.4 (9.0 - 25.7) nmol / mg protein and 18.2 (9.1 - 27.3) nmol / mg protein, respectively (P = 0.84). No differences in antral GPO enzyme activity, both of selenium (Se)-dependent and total GPO, before and after successful treatment were found. Eradication of H. pylori infection increases GST activity and GSH levels in antral mucosa. Low GST activity and GSH concentration due to H. pylori infection might play a role in gastric carcinogenesis.

A randomized controlled trial for chemoprevention of gastric cancer in high-risk Japanese population; study design, feasibility and protocol modification

We have initiated a population-based, double-blind, randomized controlled trial to examine the effects of supplementation of beta-carotene and vitamin C on the incidence of gastric cancer. The subjects were participants in an annual health screening program conducted by four municipalities in Akita prefecture, one of the regions with the highest mortality from gastric cancer in Japan. We measured their serum levels of pepsinogens (PGs) I and II, and asked persons diagnosed with chronic atrophic gastritis (defined as PG I < 70 ng/ml and PG I/PG II ratio < 3.0) to take diet supplements containing 0 or 15 mg/day beta-carotene and 50 or 500 mg/day vitamin C for 5 years. During the first year of recruitment conducted in one village from June through September, 1995, 52% (635/1214) of screening participants had chronic atrophic gastritis and 73% (439/602) of eligible persons responded. However, in response to a National Cancer Institute press report released on January 18, 1996, indicating that two beta-carotene trials had shown no benefit and potential harm from the supplement, we discontinued the beta-carotene and continued with the trial using only vitamin C. Of 397 participants remaining at this point, 77% (305) consented to stay in the study. The results indicate that a randomized controlled trial for cancer prevention is feasible in the Japanese asymptomatic population.