Coffee's Role in Dyspepsia and Gastric Acid Production
Both coffee and caffeine can cause dyspepsia and increase gastric acid production, but research suggests that compounds in coffee itself, rather than just caffeine, are the primary culprits for gastrointestinal symptoms.
Components in Coffee That Affect Gastric Function
Studies show that decaffeinated coffee stimulates gastric acid secretion at levels similar to regular coffee, and both produce higher acid responses than caffeine alone, indicating that non-caffeine components in coffee play a significant role in gastric acid production 1
Coffee contains various bioactive compounds beyond caffeine that can affect gastric function, including chlorogenic acids, β-N-alkanoyl-5-hydroxytryptamides, and N-methylpyridinium, which have varying effects on proton secretory activity in gastric cells 2
Patients with non-ulcer dyspepsia are significantly more likely to experience dyspeptic symptoms after coffee ingestion (53%) compared to healthy controls (22%), suggesting an increased sensitivity to coffee components in these individuals 3
Differential Effects of Coffee vs. Caffeine
Regular coffee and decaffeinated coffee produce similar maximal acid responses (20.9 ± 3.6 mEq per hour and 16.5 ± 2.6 mEq per hour respectively), both higher than caffeine alone (8.4 ± 1.3 mEq per hour) on a cup-equivalent basis 1
Interestingly, both regular and decaffeinated coffee significantly increased lower esophageal sphincter pressure, while caffeine showed minimal effects, further supporting that non-caffeine components in coffee affect gastrointestinal function 1
A study on patients with functional dyspepsia found that replacing both caffeinated and decaffeinated coffee with a non-caffeinated coffee substitute significantly decreased dyspeptic symptoms, suggesting that compounds specific to coffee beans contribute to symptoms 4
Coffee's Effect on Gastric Emptying
Coffee has been shown to accelerate liquid-phase gastric emptying in approximately 73% of patients with non-ulcer dyspepsia, though about 27% experienced delayed emptying after coffee ingestion 5
Altered gastric emptying (both accelerated and delayed) can contribute to dyspeptic symptoms in functional dyspepsia patients 6
Clinical Implications for Patients with Dyspepsia
For patients with functional dyspepsia, avoiding certain trigger foods, including coffee, may help manage symptoms 6
The British Society of Gastroenterology guidelines recognize that lifestyle changes, including avoiding foods that trigger symptoms, can be helpful for some patients with functional dyspepsia 6
Patients with functional dyspepsia often learn to manage their symptoms through dietary modifications and stress management 6
Functional dyspepsia is characterized by issues with the two-way communication between the upper gut and brain, with problems in the nerves supplying the stomach and duodenum potentially making them more sensitive to normal function 6
Potential Mechanisms
Chemical sensitivity to both exogenous and endogenous acid can worsen dyspeptic symptoms, particularly nausea, and is associated with decreased duodenal motility 6
Low-grade mucosal inflammation, especially in the duodenum, has been observed in patients with functional dyspepsia and may contribute to symptom generation when exposed to irritants like coffee 6
Both mechanical and chemical hypersensitivity have been demonstrated in subgroups of patients with functional dyspepsia, which may explain heightened responses to coffee ingestion 6
In summary, while both coffee and caffeine can increase gastric acid production and cause dyspeptic symptoms, the evidence suggests that compounds specific to coffee itself, rather than just caffeine, are primarily responsible for these effects in susceptible individuals.