Dietary Factors
Helicobacter Pylori Infection
Chemoprevention

Note: Separate PDQ summaries on Stomach (Gastric) Cancer Screening ¹, Gastric Cancer Treatment ², and Levels of Evidence for Cancer Screening and Prevention Studies ³ are also available.

Based on fair evidence, excessive salt intake and deficient dietary consumption of fresh fruits and vegetables are associated with an increased risk of gastric cancer. Dietary intake of vitamin C contained in vegetables, fruits, and other foods of plant origin is associated with a reduced risk of gastric cancer. Diets high in whole-grain cereals, carotenoids, allium compounds, and green tea are also associated with a reduced risk of this cancer. However, it is uncertain if changing one's diet to include more vegetables, fruits, and whole grains would reduce the risk of gastric cancer.

Description of the Evidence

• Study Design: Evidence obtained from cohort or case-control studies.
• Internal Validity: Good.
• Consistency: Small number of studies.
• Magnitude of Effects on Health Outcomes: Small, difficult to determine.
• External Validity: Fair (populations vary greatly in their underlying nutritional status).

Based on solid evidence, Helicobacter pylori infection is associated with an increased risk of gastric cancer, however, the evidence is inadequate to determine if treatment with antibiotics reduces the risk of developing gastric cancer.

Description of the Evidence

• Study Design: Evidence obtained from cohort or case-control studies.
• Internal Validity: Good.
• Consistency: Good, multiple studies.
• Magnitude of Effects on Health Outcomes: Increased risk, moderate magnitude.
• External Validity: Good.

The evidence is inadequate to determine if dietary or antibiotic interventions will reduce the risk of developing gastric cancer. A chemoprevention trial in China reported a statistically significant reduction of gastric cancer mortality after supplementation with beta carotene, vitamin E, and selenium.

Description of the Evidence

• Study Design: Evidence obtained from randomized controlled trials.
• Internal Validity: Fair.
• Consistency: Poor.
• Magnitude of Effects on Health Outcomes: Cannot determine.
• External Validity: Fair.