Effect of Olestra on Faecal Water and Short-chain Fatty Acids

To determine the effect of olestra on microbial ecology of the gut, faecal short-chain fatty acids (SCFAs) and water content were assessed in 93 subjects in a 36 d parallel, placebo-controlled, double-blind study. Faecal SCFAs and water content were determined at the end of an 8 d low fibre baseline period and 28 d treatment period. The test meal consisted of either a moderate (7 g) or high (24 g) level of fibre and olestra (24 g) or an equivalent amount of conventional fat. Olestra had a significant effect on both faecal water content and SCFAs. The water content decreased and concentrations of some SCFAs increased. The effect of olestra on SCFA concentrations in faeces (mmol/kg) differed with different fibre content of the meal. When the SCFAs were expressed as mmol/1 faecal water, a similar pattern of changes (several SCFAs increased) was observed for both olestra groups. Although all individual SCFA values were within the range of a healthy population, the effects were consistent, and potential reasons for it are discussed.