Different effects of Western and Mediterranean diets on gut microbiota: metagenomic and metabolomic approaches.

Nutrients 2021, 13(8), 2638. https://doi.org/10.3390/nu13082638

Commentary

The aim of this study was to investigate the effects of diet on gut microbiota, digestive function and sensation using an integrated clinical, metagenomic and metabolomic approach.

A crossover, randomized study was conducted on the effects of a Western-style diet and a Mediterranean-style diet, which is rich in fiber.

Twenty eligible healthy men were given each diet for two weeks, followed by a two-week washout diet, and the following results were recorded.

(a) Number of times anal gas was expelled

(b) Digestive sensation

(c) Amount of gas expelled after the probe meal

(d) Colonic contents by magnetic resonance imaging 

(e) Classification and metabolic function of intestinal bacteria by shotgun sequencing of fecal samples.

(f) Urinary metabolites using non-targeted metabolomics.

Compared to the Western diet, the Mediterranean diet

(i) Number of antral gas emissions

(ii) sensation of flatulence and belching

(iii) Large amount of gas after meals

(iv) greater colonic content.

It was reported that these were more common.

Despite relatively small differences in the composition of the microbiota in both diets, microbial metabolism yielded substantially different results, as indicated by the profile of urinary metabolites and the abundance of microbial metabolic pathways.

It was also reported that the effects of diet did not show different results in individuals with robust microbiota.

These conclude that healthy individuals tolerate dietary changes that involve slight microbial modifications at the compositional level, but with marked variations in microbial metabolism.