Letter: dietary fibre benefits for the oesophagus—physical rather than metabolic action?

Abstract

EDITORS, We read with interest the recent paper by O Grady et al. The authors present a modern perspective on fibre science and argue that soluble fibre may delay gastric emptying and digestion and thus aggravate upper abdominal symptoms. The article by Piche et al, which the authors refer to, described the effect of ingested (and fermented in the colon) fructooligosaccharides (FOS) on transient lower oesophageal sphincter relaxations (TLESR) in GERD. The study showed that an increased number of TLESR in GERD patients could be explained by colonic fermentation of FOS and humoral pathways of the effect mediated by glucagon‐like peptide‐1. Precise evaluation of the data provided showed that most of the patients in the study had signs of small intestinal bacterial overgrowth according to the hydrogen breath test, which could have impacted the study results. Our own data suggest the contrary: soluble fibre (psyllium) leads to a significant improvement of symptoms in patients with non‐erosive GERD, rather than exacerbate them. Moreover, addition of soluble fibre leads to a decrease in the number of gastro‐oesophageal refluxes per 24-hour oesophageal pH‐impedance monitoring and an increase in minimal lower oesophageal sphincter resting pressure. This corresponds to population studies which demonstrate inverse correlation between the amount of fibre intake and frequency of heartburn, as well as protective effects of dietary fibre with regard to the risks of oesophageal adenocarcinoma development. A possible explanation of these data is that at least some of the soluble fibres may increase gastric emptying and decrease the acidity of its content. They also may bind nitric oxide contained in the food thus reducing its negative impact on lower oesophageal sphincter (LES) pressure. This shows that the benefits of dietary fibre to the oesophagus can hardly be explained solely by metabolic (prebiotic‐like) effects —they seem to be more physical. On the other hand, critical evaluation of the research data, especially with discrepant results, is necessary. We do not doubt the importance of dietary fibre metabolic effects. However, there is not yet enough evidence available on the type and the amount of the fibre (or combination of them) needed in a certain condition. To explore these matters and achieve a better understanding of the dietary fibre mechanisms of action, we need further randomised interventional studies with different types of dietary fibre and in different conditions. ACKNOWLEDGEMENTS