Deciphering the Impact of Coffee on the Upper Gastrointestinal Tract: Correlation or Causation?

Background and aims: The role of coffee consumption in upper gastrointestinal (GI) diseases has been a topic of ongoing debate. While some studies suggest a potential association, the causal relationship remains unclear. This critical review evaluated the evidence linking coffee consumption to upper GI diseases via Hill’s criteria for causation.Methods: By performing a comprehensive literature search across many databases, such as PubMed, Scopus, and Google Scholar, the author was able to find relevant papers. Once the article had been downloaded, it was imported into the reference manager. The author then manually screens the article for duplicate references by using author names, journals, and publication years. Studies were identified and critically reviewed using Hill’s criteria to assess the causality of this relationship.Results: The findings remain inconclusive. The strength of the associations between coffee consumption and specific upper GI conditions, such as gastroesophageal reflux disease (GERD), peptic ulcers, and esophageal cancer, varied significantly across studies. Temporality was challenging to establish because of the observational nature of most studies. Biological plausibility exists, supported by evidence of the effect of coffee on gastric acid secretion and motility. However, dose‒response relationships and experimental evidence are inconsistent. Overall, the review concluded that the evidence supports a correlation, but the causal nature of the relationship remains inconclusive.Conclusion: The evidence reviewed suggests a weak correlation between coffee consumption and upper GI diseases, with insufficient support for a direct causal link. While coffee may influence certain GI parameters, confounding factors and study design limitations preclude definitive conclusions.