Gassy acids

The consumption of beer is, for some, one of life’s great pleasures but it can leave behind a bitter aftertaste.

A team of researchers in Austria and Germany has undertaken a study that has revealed that the bitter acids in hops stimulate gastric acid secretion.1 The team compared the effects of five different beers on mechanisms of gastric acid secretion. Organic acids and bitter compounds were quantified by HPLC–DAD and UPLC–MS–MS and tested in human gastric cancer cells (HGT-1). This was performed using a pH-sensitive fluorescent dye that determines the intracellular pH and would indicate proton secretion. They also measured the expression of four genes, coding the H+/K+-ATPase, ATP4A, the histamine receptor, HRH2, the acetylcholine receptor, CHRM3, and the somatostatin receptor, SSTR2, by quantitative polymerase chain reaction (qPCR).

Ethanol and the organic acids succinic acid, malic acid and citric acid contributed to some extent to the effect of beer. The bitter acids, α-, ß- and iso-α-acids, were identified as potential components promoting gastric acid secretion. They also promoted up-regulation of CHRM3 gene expression by a maximum factor of 2.01 compared with that of untreated control cells with a correlation to their respective bitterness.

The potential is, therefore, present for brewers to produce beers that do not generate gastric acids in a large quantity.

1. Veronika Somoza et al., J. Agric, Food Chem., 60(6), 1405–1412 (2012).