In vitro fermentation of different types of dietary fiber in ulcerative colitis: Production of butyrate

Abstract

In a previous study we observed that a dietary fiber which yields butyrate in the colon (Plantago ovata seeds) was able to maintain remission in ulcerative colitis (UC) as compared to mesalazine (Am J Gastroenterol 1999). Recently, different studies have shown that butyrate may have an anti-inflammatory effect by modulating the release of pro-inflammatory cytokines. Aim: To assess in vitro the ability of different types of dietary fiber to yield short chain fatty acids (SCFA), especially butyrate, in patients with UC in remission. Methods: Fresh stools specimens were collected from 8 patients with UC in remission. Fecal homogenates (feces diluted 1:5 with sodium bicarbonate) were incubated under anaerobic conditions (nitrogen), at 37°C for 0, 6 and 24 h, with the different types of fiber as dry power (20 mg/ml): Fiber A, Plantago ovata seeds; Fiber B, Plantago ovata husk (POH); Fiber C, POH+ Resistant starch 1 g; Fiber D, POH+Resistant starch 0.5 g. Fecal suspensions without additions served as control. The bacterial fermentation was stopped by freezing at -80°C. SCFAs were determined by GLC using a semicapilar column. Friedman s two-way analysis of variance for repeated measures was used in the statistical analysis. Results: A significant increase in total SCFA production at 6 hand 24 h was observed with all fibers as compared to basal values. Results at 6 h and 24 h are shown in the Table (a% respect to basal value; p<0.005 vs No fiber at 24 h). Butyrate levels were higher with Fiber A than with the other types of fiber (24 h: 19.6±3 vs 13.6±3, l6.2±3, l4.1±3 mmol/g, p=0.07 vs others and p=0.04 vs Fiber B; 8.3±O.8 vs 5.2±0.7, 6.5±O.9, 5.4±0.6 percent of Total SCFAs, p=O.OO6 vs others). Conclusions: Although all types of fiber studied produce in vitro similar amounts of SCFA, Plantago ovata seeds showed a higher trend to produce butyrate. 4763