Effect of regular and decaffeinated coffee on serum gastrin levels

Caffeine intake enhances bowel recovery after colorectal surgery: a meta-analysis of randomized and non-randomized studies

Postoperative ileus (POI) after colorectal surgery is a major problem that affects both patient recovery and hospital costs highlighting the importance of preventive strategies. Therefore, we aimed to perform a systematic analysis of the effects of postoperative caffeine consumption on bowel recovery and surgical morbidity after colorectal surgery. A comprehensive literature search was conducted through September 2023 for randomized and non-randomized trials comparing the effect of caffeinated versus non-caffeinated drinks on POI by evaluating bowel movement resumption, time to first flatus and solid food intake, and length of hospital stay (LOS). Secondary outcome analysis included postoperative morbidity in both groups. After data extraction and inclusion in a meta-analysis, odds ratios (ORs) for dichotomous variables and standardized mean differences (SMDs) for continuous outcomes with 95% confidence intervals (CIs) were calculated. Subgroup analyses were performed in cases of substantial heterogeneity. Six randomized and two non-randomized trials with a total of 610 patients were included in the meta-analysis. Caffeine intake significantly reduced time to first bowel movement [SMD -0.39, (95% CI -0.66 to -0.12), p = 0.005] and time to first solid food intake [SMD -0.41, (95% CI -0.79 to -0.04), p = 0.03] in elective laparoscopic colorectal surgery, while time to first flatus, LOS, and the secondary outcomes did not differ significantly. Postoperative caffeine consumption may be a reasonable strategy to prevent POI after elective colorectal surgery. However, larger randomized controlled trials (RCTs) with homogeneous study protocols, especially regarding the dosage form of caffeine and coffee, are needed.

Effects of Coffee on the Gastro-Intestinal Tract: A Narrative Review and Literature Update

The objective of the present research was to review the state of the art on the consequences of drinking coffee at the different levels of the gastrointestinal tract. At some steps of the digestive process, the effects of coffee consumption seem rather clear. This is the case for the stimulation of gastric acid secretion, the stimulation of biliary and pancreatic secretion, the reduction of gallstone risk, the stimulation of colic motility, and changes in the composition of gut microbiota. Other aspects are still controversial, such as the possibility for coffee to affect gastro-esophageal reflux, peptic ulcers, and intestinal inflammatory diseases. This review also includes a brief summary on the lack of association between coffee consumption and cancer of the different digestive organs, and points to the powerful protective effect of coffee against the risk of hepatocellular carcinoma. This review reports the available evidence on different topics and identifies the areas that would most benefit from additional studies.

Protection against developing type 2 diabetes by coffee consumption: assessment of the role of chlorogenic acid and metabolites on glycaemic responses

Epidemiological studies show a convincing long-term and dose-dependent protection of coffee and decaffeinated coffee against developing type 2 diabetes. The mechanisms of this effect are still not understood even though several have been proposed, including a potential effect on blood glucose by chlorogenic acids. However, there is minimal effect of decaffeinated coffee on postprandial blood glucose and insulin when consumed with carbohydrates, although there may be effects on incretin hormones, but these have been measured in only a few studies. Although chlorogenic acids do not affect carbohydrate digestion directly, they may affect glucose absorption and subsequent utilisation, the latter through metabolites derived from endogenous pathways or action of the gut microbiota. To advance understanding of the protective effect of coffee chlorogenic acids, more chronic intervention studies are needed on decaffeinated coffee, coupled with mechanistic studies in vitro using more realistic concentrations of the relevant chlorogenic acid metabolites.

Acute effects of coffee consumption on self-reported gastrointestinal symptoms, blood pressure and stress indices in healthy individuals

Background

It has been suggested that coffee may affect the gut-brain axis with conflicting outcomes. Moreover, there is insufficient evidence to determine whether the type or temperature of coffee consumed will have a different impact on the gut-brain axis. The purpose of this study was to investigate the effects of acute coffee consumption on the following: 1. self-reported GI symptoms and salivary gastrin, 2. stress indices [salivary cortisol and alpha-amylase (sAA)] and psychometric measures, and 3. blood pressure (BP), in healthy, daily coffee consuming individuals in non-stressful conditions.

Methods

This was a randomized, double blind, crossover clinical trial, in which 40 healthy individuals (20 men, 20 women), 20–55 years of age, randomly consumed four 200 ml coffee beverages containing 160 mg caffeine (hot and cold instant coffee, cold espresso, hot filtered coffee), 1 week apart. Salivary samples and psychometric questionnaires were collected at baseline and post-coffee consumption at 15,30, and 60 min for salivary gastrin and sAA measurements and at 60,120, and 180 min for cortisol measurements. BP was measured at beginning and end of each intervention. ClinicalTrials.gov ID: NCT02253628

Results

Coffee consumption significantly increased sAA activity (P = 0.041), with significant differences only between cold instant and filter coffee at 15 and 30 min post-consumption (P < 0.05). Coffee temporarily increased salivary gastrin, without differences between coffee types. Coffee did not affect salivary cortisol or self-reported anxiety levels. Coffee consumption significantly increased BP, within the healthy physiological levels, in a gender specific manner at the end of the experimental periods, without differences between coffee types.

Conclusion

Acute coffee consumption in non-stressful conditions activated sAA and BP but not salivary cortisol, indicating activation of the sympathetic nervous system. Post-coffee sAA increase without a concomitant cortisol increase may also indicate that coffee may have some anti-stress properties.

Multi-parametric approach to identify coffee components that regulate mechanisms of gastric acid secretion

SCOPE

Chlorogenic acid (CA), caffeine (CAFF), pyrogallol (PYR), catechol (CAT), (β)N-alkanoyl-hydroxytryptamides (C5HT) and N-methylpyridinium (N-MP) were evaluated for their influence on mechanisms of gastric acid secretion as single compounds and in biomimetic mixtures.

METHODS AND RESULTS

Compounds were tested in coffee representative concentrations. Human gastric cancer cells (HGT-1) were used to study the proton secretory activity by Ussing chamber experiments and FACS analysis. For activation of EGFr, Akt1, ERK1/2, ATF-2 and cAMP levels, we performed pathway screening assays. Time-dependent expression of related genes were determined by real-time PCR. Part of the data was used for neural network modeling to identify the most relevant compounds. N-MP increased the expression of the anti-secretory somatostatin receptor by 114%, whereas C5HT decreased its expression by 52%. N-MP down-regulated the pro-secretory CHRM3 receptor by 36% and the H⁺,K⁺-ATPase by 36%. CAFF stimulated the secretory activity in the functional assays, whereas N-MP and CA decreased proton secretion. After applying a pathway analysis, we were able to discriminate between CAFF, CA, CAT, C5HT, PYR and histamine-activating EGFr signaling and N-MP-associated ERK1/2 signaling.

CONCLUSION

By applying a multi-parametric approach, N-MP was shown to effectively down-regulate mechanisms of gastric acid secretion in human parietal gastric cells.

Activity-guided fractionation to characterize a coffee beverage that effectively down-regulates mechanisms of gastric acid secretion as compared to regular coffee

In some individuals, the consumption of coffee beverages is related to symptoms of gastric irritation. Hot water steam-treatment of raw coffee beans is hypothesized to reduce the contents of stomach irritating compounds, and products to which this technology is applied are launched as stomach-friendly coffee. However, data on the effect of steam-treated coffee on gastric acid secretion are conflicting and it has not been proven yet as to which coffee components act as pro- or antisecretory stimulants. The work presented here aimed at the characterization of a coffee beverage that effectively down-regulates mechanisms of proton secretion in human gastric cells (HGT-1). At first, a regular coffee beverage was fractionated by using solvents of different polarity: water, ethylacetate, dichloromethane, and pentane. Functional assays on the proton secretory activity (PSA) of these solvent fractions revealed the least pronounced effect for the water fraction, for which quantitative analyses demonstrated the highest distribution of chlorogenic acid (95%), (beta)N-alkanoyl-5-hydroxytryptamides (55%), and N-methylpyridinium (N-MP, >99%) among all fractions. Following experiments demonstrated that HGT-1 cells treated with regular coffee fortified with N-MP at a concentration of about 20 mg/mL N-MP showed a significantly decreased PSA as compared to cells which were exposed to coffee beverages containing higher (32-34 mg/L) or lower (5 mg/L) N-MP concentrations. Results from cellular pathway analyses of transcription (ATF-1 and Akt1) and signaling (cAMP and EGFr) factors and kinases (ERK1/2), and experiments on the gene expression of pro (histamine-HRH2 and acetylcholine-CHRM3)- and anti (somatostatin-SSTR1)-secretory receptors and H(+),K(+)-ATPase verified this antisecretory activity of N-MP in coffee beverages.

Quantitation of (beta)N-Alkanoyl-5-hydroxytryptamides in coffee by means of LC-MS/MS-SIDA and assessment of their gastric acid secretion potential using the HGT-1 cell assay

A straightforward stable isotope dilution analysis (SIDA) for the reliable quantitative determination of (beta)N-C(18:0)- to (beta)N-C(24:0)-alkanoyl-5-hydroxytryptamides (C5HTs) in coffee powder and beverages by means of LC-MS/MS was developed. The developed SIDA showing accuracy values of 92.6-107% and precision between 0.5 and 7% relative standard deviation for the individual derivatives allowed the sensitive and selective quantification of the target compounds in coffee beverages. Depending on the type of coffee, quantitation revealed C5HT levels between 65 and 144 microg/L in filtered coffee and up to 3500 microg/L in a French press beverage, thus indicating that about 0.3 or 7.2% of the C5HTs were extracted from the coffee powder into the beverage when using the cellulose filter method or the French press, respectively. To estimate the potential contribution of the C5HTs to the phenomenon of stomach irritation after ingestion of coffee brew, in vitro cell studies were performed with pure individual 5-hydroxytryptamides and a mixture of the predominating derivatives in ratios matching those found in coffee. All substances tested induced a decrease in the intracellular proton index (IPX) coined as an indicator of stomach acid secretion. While the biomimetic C5HT mixture was highest in its inducing effect, the individual stearic acid, oleic acid, and linoleic acid 5-hydroxytryptamide did not differ significantly from each other, but showed a less pronounced effect compared to arachinic acid 5-hydroxytryptamide. In conclusion, not the grade of saturation seems to determine the C5HT's mode of action in driving the stomach acid secretion, rather than the fatty acid chain length.

Effects of caffeine on gastrointestinal myoelectric activity and colonic spike activity in dogs

BACKGROUND

Caffeine is known to produce various effects on the gastrointestinal tract. Few studies have, however, investigated the effects of caffeine on gastrointestinal myoelectric activity under physiologic conditions. The aims of this study were to investigate the effects of caffeine on colonic motility (spike activity) and gastric and jejunal slow waves in conscious dogs.

METHODS

The study was performed in eight healthy female hound dogs (15-20 kg) in which one pair of electrodes was implanted on the serosa of the stomach, one pair on the proximal jejunum, and another pair on the ascending colon. The protocol consisted of a 60-min recording as base line and a 90-min recording after intravenous injection of saline, a low dose of caffeine (125 mg), or a high dose of caffeine (250 mg).

RESULTS

In the colon there was a significant increase in the number of spike bursts per minute after the injection of both the low (6.69+/-1.27 versus 8.22+/-1.31, P < 0.05) and the high dose (4.38+/-1.23 versus 6.92+/-0.98, P < 0.05) of caffeine. The increase in the total energy of spikes per minute after the injection of the high dose of caffeine was significantly higher than that after the low dose of caffeine (41.2+/-14.6 versus 133.4+/-39.2, P < 0.05). The characteristics of the gastric and jejunal slow waves were, however, not affected by caffeine.

CONCLUSION

Caffeine increases spike activity in the colon, and its effect may be dose-dependent. Gastric and jejunal slow waves are not affected by caffeine.

The effect of coffee on gastric emptying and oro-caecal transit time

BACKGROUND

The consumption of coffee allegedly induces or aggravates gastrointestinal symptoms. In order to investigate the effect of coffee on gastrointestinal motility we studied the effect of coffee on gastric emptying and oro-caecal transit time.

METHODS

In a randomised, controlled, cross-over study gastric emptying and oro-caecal transit time were studied in 12 healthy volunteers, using applied potential tomography and lactulose hydrogen breath test, respectively. After 1 day of coffee abstinence and an overnight fast, coffee or the control drink (water) was drunk and 10 min thereafter a liquid nutrient meal was ingested together with lactulose. During 150 min, recordings were made with applied potential tomography and breath samples were taken every 5 min. Lag-phase duration and gastric half-emptying time were determined by two blinded observers.

RESULTS

The lag-phase duration after coffee (median 19.8 min, range 6-47 min) was not significantly different from that after water (median 19.3 min, range 11-37.5), nor was the gastric half-emptying time (median 75.7 min, range 56-157.6 vs. median 83.4 min, range 64. 6-148.4). Likewise, coffee had no significant effect on oro-caecal transit time (median 135 min, range 60-270 vs. median 140 min, range 55-270). No significant correlation between any of these parameters and mean daily coffee intake was found.

CONCLUSIONS

Coffee does not affect gastric emptying of a liquid meal or small bowel transit.

Coffee and gastrointestinal function: facts and fiction. A review

BACKGROUND

Effects of coffee on the gastrointestinal system have been suggested by patients and the lay press, while doctors tend to discourage its consumption in some diseases.

METHODS

The literature on the effects of coffee and caffeine on the gastrointestinal system is reviewed with emphasis on gastrointestinal function.

RESULTS

Although often mentioned as a cause of dyspeptic symptoms, no association between coffee and dyspepsia is found. Heartburn is the most frequently reported symptom after coffee drinking. It is demonstrated that coffee promotes gastro-oesophageal reflux. Coffee stimulates gastrin release and gastric acid secretion, but studies on the effect on lower oesophageal sphincter pressure yield conflicting results. Coffee also prolongs the adaptive relaxation of the proximal stomach, suggesting that it might slow gastric emptying. However, other studies indicate that coffee does not affect gastric emptying or small bowel transit. Coffee induces cholecystokinin release and gallbladder contraction, which may explain why patients with symptomatic gallstones often avoid drinking coffee. Coffee increases rectosigmoid motor activity within 4 min after ingestion in some people. Its effects on the colon are found to be comparable to those of a 1000 kCal meal. Since coffee contains no calories, and its effects on the gastrointestinal tract cannot be ascribed to its volume load, acidity or osmolality, it must have pharmacological effects. Caffeine cannot solely account for these gastrointestinal effects.

CONCLUSIONS

Coffee promotes gastro-oesophageal reflux, but is not associated with dyspepsia. Coffee stimulates gallbladder contraction and colonic motor activity.

Lower esophageal sphincter pressure, acid secretion, and blood gastrin after coffee consumption

This study tested the hypothesis that differences in the processing of raw coffee beans can account for some of the variability in gastric effects of coffee drinking. Coffees were selected to represent several ways that green coffee beans are treated, ie, processing variables. These included instant and ground coffee processing, decaffeination method (ethyl acetate or methylene chloride extraction), instant coffee processing temperature (112 degrees F or 300 degrees F), and steam treatment. Lower esophageal sphincter pressure, acid secretion, and blood gastrin was measured in eight human subjects after they consumed each of the different coffees. Consumption of coffee was followed by a sustained decrease in lower esophageal sphincter pressure (P less than 0.05) except for three of the four coffees treated with ethyl acetate regardless of whether or not they contained caffeine. Caffeinated ground coffee stimulated more acid secretion that did decaf ground coffees (P less than 0.05), but not more than a steam-treated caffeinated coffee. Instant coffees did not differ in acid-stimulating ability. Ground caffeinated coffee resulted in higher blood gastrin levels than other ground coffees (P less than 0.05). Freeze-dried instant coffee also tended toward higher gastrin stimulation. It is concluded that some of the observed variability in gastric response to coffee consumption can be traced to differences in how green coffee beans are processed.

Effect of coffee on distal colon function

Ninety nine healthy young volunteers (58 men, 34 women, aged 17-27 years) answered a questionnaire concerning their bowel habit with particular reference to the effects of beverages. Twenty nine per cent (63% women) claimed that coffee induced a desire to defecate. The rectosigmoid motor responses to black, unsweetened coffee were then investigated by multiport manometry in 14 healthy-subjects (12 men, two women, eight of whom claimed coffee caused a desire to defecate (responders). Results revealed an increase in motility index within four minutes after ingestion of both regular and decaffeinated coffee (p less than 0.05) in the eight responders, but not in the six non-responders. The increase in rectosigmoid motility induced by coffee lasted at least 30 minutes. There was no increase in the motility index in any subject after a drink of hot water. These results suggest that drinking coffee can stimulate a motor response of the distal colon in some normal people.