A dark brown roast coffee blend is less effective at stimulating gastric acid secretion in healthy volunteers compared to a medium roast market blend.

Coffee consumption sometimes is associated with symptoms of stomach discomfort. This work aimed to elucidate whether two coffee beverages, containing similar amounts of caffeine, but differing in their concentrations of (ß) N-alkanoyl-5-hydroxytryptamides (C5HTs), chlorogenic acids (CGAs), trigonelline, and N-methylpyridinium (N-MP) have different effects on gastric acid secretion in healthy volunteers. The intragastric pH after administration of bicarbonate with/without 200 mL of a coffee beverage prepared from a market blend or dark roast blend was analyzed in nine healthy volunteers. Coffee beverages were analyzed for their contents of C5HT, N-MP, trigonelline, CGAs, and caffeine using HPLC-DAD and HPLC-MS/MS. Chemical analysis revealed higher concentrations of N-MP for the dark brown blend (87 mg/L) compared to the market blend coffee (29 mg/L), whereas concentrations of C5HT (0.012 versus 0.343 mg/L), CGAs (323 versus 1126 mg/L), and trigonelline (119 versus 343 mg/L) were lower, and caffeine concentrations were similar (607 versus 674 mg/mL). Gastric acid secretion was less effectively stimulated after administration of the dark roast blend coffee compared to the market blend. Future studies are warranted to verify whether a high ratio of N-MP to C5HT and CGAs is beneficial for reducing coffee-associated gastric acid secretion.

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

SCOPE: Chlorogenic acid (CA), caffeine (CAFF), pyrogallol (PYR), catechol (CAT), (ß)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.

Measurement of the intracellular ph in human stomach cells: a novel approach to evaluate the gastric acid secretory potential of coffee beverages.

As the consumption of coffee beverages sometimes is reported to cause gastric irritation, for which an increased stomach acid secretion is one of the promoting factors, different processing technologies such as steam-treatment have been developed to reduce putative stomach irritating compounds. There is evidence-based data neither on the effect of detailed processing variations nor on individual coffee components affecting the proton secretory activity (PSA). This work aimed at developing a screening model suitable for investigating the effects of commercial coffee beverages and components thereof on human parietal cells. Human gastric cancer cells (HGT-1) were treated with reconstituted freeze-dried coffee beverages prepared from customary coffee products such as regular coffee (RC, n = 4), mild bean coffee (MBC, n = 5), stomach friendly coffee (SFC, n = 4), and SFC decaffeinated (SFCD, n = 3). PSA was analyzed by flow cytometry using the pH-sensitive dye SNARF-AM. Treatment of the cells with MBC did not result in a PSA different from RC treatment (p

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.