The role of dietary components in upper gastrointestinal cancers: A narrative review

Esophageal and gastric cancers together account for approximately 17% of global cancer deaths. The main modifiable risk factors are Helicobacter pylori infection, gastroesophageal reflux disease (GERD), and dietary patterns.

This narrative review synthesizes evidence on the roles of dietary components- Phytochemicals, probiotics, carotenoids, cysteine/taurine/homocysteine, arginine/citrulline/NO, glutamine, and carnitine-in UGI cancer epidemiology, etiology, prevention, and treatment.

A narrative synthesis of literature from 2010 to 2025 was conducted using PubMed and Google Scholar, focusing on mechanistic and clinical insights.

Phytochemicals found in vegetables inhibit cancer cell proliferation and metastasis, although their efficacy is limited by poor bioavailability. Probiotics enhance Helicobacter pylori eradication and attenuate inflammation, potentially reducing gastric cancer risk. Carotenoids, including α-carotene and β-carotene, have shown promise in lowering the risk of esophageal and gastric cancers, though evidence remains inconsistent. Certain amino acids-namely cysteine, taurine, homocysteine, arginine, and glutamine-play dual roles in regulating redox balance and tumor metabolism. In contrast, carnitine intake has been associated with an elevated risk of gastric cancer, particularly in men.

Nutritional interventions have the potential to modulate UGI carcinogenesis; however, fragmented evidence, variable study designs, and regional dietary differences highlight the need for large-scale clinical trials to develop standardized guidelines.