Do polysorbate 80 and sodium nitrite affect differently the gut microbiota of healthy individuals and IBD patients ?

Intestinal fibrosis is a long–term complication of inflammatory bowel diseases (IBD). Changes in microbial populations have been linked with the onset of fibrosis and some food additives are known to promote intestinal inflammation facilitating the induction of fibrosis. Most of these studies have been performed in murine models or in healthy donors while the effects of food additives on intestinal microbiota of patients suffering from IBD is less understood. The aim of this work was therefore to determine how food additives affect intestinal microbiota of both healthy and “IBD” donors. Two food additives, polysorbate 80 (P80) and sodium nitrite, were tested in a short-term (72h) in vitro model of human intestinal microbiota. Three groups of donors were investigated: healthy persons (H), patients in remission of IBD (R) and patients with an active period of IBD (A). Changes in microbiota metabolome (short chain fatty acids) were assessed by SPME-GC/MS while the evolution of microbial populations positively or negatively correlated with health, inflammation and/or fibrosis was assessed by qPCR analysis. Polysorbate 80 significantly and deeply decreased propionate and butyrate production in H group. Conversely, in R group, an increase in both propionate and butyrate production was observed. Moreover, with P80, Ruminococcus, correlated with increased risk of fibrosis, was increased in H group and Oscillospira related with reduced risk of fibrosis, was decreased in H and A groups. Regarding the supplementation with sodium nitrite, a significant increase in propionate production in R group and a decrease in butyrate production in A group were observed. Sodium nitrite also decreased Oscillospira in A group. This study demonstrates how strongly the human microbiota can be affected by some food additives. In addition, to our knowledge, this is the first human in vitro study focusing on the impact of food additives on microbiota of IBD patients.