The human gut microbial ecology associated with overweight and obesity determines ellagic acid metabolism

We recently identified three metabotypes (0, A and B) that depend on the metabolic profile of urolithins produced from polyphenol ellagic acid (EA). The gut microbiota and Gordonibacter spp. recently were identified as species able to produce urolithins. A higher percentage of metabotype B was found in patients with metabolic syndrome or colorectal cancer in comparison with healthy individuals. The aim of the present study was to analyse differences in EA metabolism between healthy overweight-obese and normoweight individuals and evaluate the role of gut microbial composition including Gordonibacter. Although the three metabotypes were confirmed in both groups, metabotype B prevailed in overweight-obese (31%) versus normoweight (20%) individuals while metabotype A was higher in normoweight (70%) than the overweight-obese group (57%). This suggests that weight gain favours the growth of bacteria capable of producing urolithin B and/or isourolithin A with respect to urolithin A-producing bacteria. Gordonibacter spp. levels were not significantly different between normoweight and overweight-obese groups but higher Gordonibacter levels were found in metabotype A individuals than in those with metabotype B. Other bacterial species have been reported to show a much closer relationship to obesity and dysbiosis than Gordonibacter. However, Gordonibacter levels are negatively correlated with metabotype B, which prevails in metabolic syndrome and colorectal cancer. This is the first report that links overweight and obesity with an alteration in the catabolism of EA, and where the correlation of Gordonibacter to this alteration is shown. Future investigation of Gordonibacter and urolithin metabotypes as potential biomarkers or therapeutic targets of obesity-related diseases is warranted.