Abstract
To determine the effect of olestra on microbial ecology of the gut five microflora associated characteristics (MACs) were assessed in 93 subjects in a 36 d parallel, placebo-controlled, double-blind study. Degradation of tryptic activity, β-aspartylglycine and mucin, and conversion of cholesterol to coprostanol and bilirubin to urobilinogen were determined in faecal samples collected 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 no effect on degradation of tryptic activity or β-aspartylglycine, and no consistent effect on mucin degradation. Olestra reduced significantly the conversion of cholesterol to coprostanol and urobilin to urobilinogen although the individual values were all within the range of healthy population after treatment. The lipophilic nature of cholesterol and urobilin is the most likely reason for the findings, as parts of the substrates partition into olestra and are not available to microorganisms.
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