Faecal tryptic activity and excretion of urobilins in 573 healthy subjects living in Sweden, Norway and Scotland

Abstract

The aim of the present study was to establish reference values with respect to two microflora-associated characteristics (MACs), i.e. faecal tryptic activity (FTA) and excretion of urobilins in healthy human subjects. These parameters were determined in faecal samples from 573 individuals living in Sweden, Norway or Scotland and examined for possible relationships to age (<36 years, 36–50 years and >50 years old) and gender. Since no differences between countries were observed, these three sets of data were pooled for this analysis. In general, the levels of FTA were higher in men, significantly so in the two younger age groups (192, 105, 50 vs 60, 53, 39 mg/kg faeces in men and women, respectively) (p<0.05). Faecal levels of urobilins were significantly higher in men than in women at all ages (1.31, 1.13, 1.37 vs 1.03, 0.89, 0.99 mmol/kg faeces in men and women, respectively). Furthermore, in 36–50-year-old men the mean level of urobilins was significantly lower than for men in the other two age groups. In the case of women, the highest corresponding values were observed in the youngest age group. These results provide reliable reference values for two MACs which are important factors in intestinal host–microbial cross-talk and will be useful in future studies concerning the influence of exogenous factors on such interactions.