Many epidemiological and experimental studies have suggested an important role for dietary fibre (DF) of cereals in the prevention of colon cancer. The objective of the present study was to explain the effects of the DF of barley Rihane (BR) on azoxymethane (AOM)-induced aberrant crypt foci (ACF) and colonic bacterial diversity in rats. Following an acclimatisation period, rats were divided into four groups and fed a control (C) diet or experimental diet containing 30 % of BR. DF content in the experimental diet was twice that of the C diet (total DF was 8·69 % in the C diet and 15·24 % in the BR diet). At 7 and 8 weeks of age, rats received two successive subcutaneous injections of AOM at 20 mg/kg body weight. At 12 weeks after the first injection, ten animals from each group were killed. The BR diet decreased colonic pH (P < 0·05) compared with the C diet. The total number of ACF observed decreased considerably in the BR/AOM group compared with the C/AOM group (P < 0·05). Comparison of similarity coefficients showed variability of colonic microbiota species between the different groups. In addition, we showed inter-individual variability within the same group. This similarity was affected by BR and AOM. The present results show that bifidobacteria numbers were lower in rats fed the BR diet compared with those fed the C diet. However, the number of enterobacteria in colonic content was increased (P < 0·05) in the BR group compared with the C group. The results from the present study show that the DF of BR reduced the incidence of AOM-induced ACF and increased microbiota biodiversity.

Breath hydrogen excretion was measured in eight lactase (EC 3.2.1. 108)-deficient volunteers ingesting 18 g lactose in the form of milk, yoghurt and heated yoghurt. Total excess hydrogen excretion (area under curve) was significantly lower after yoghurt and heated yoghurt, than after milk: 103 (SE 29), 191 (SE 32), and 439 (SE 69) respectively (P < 0.001). The oro-caecal transit time of fermentable components from yoghurt and heated yoghurt (mainly lactose) was longer than that from milk: 165 (SE 17), 206 (SE 19), v. 103 (SE 19) min (P < 0.01). An intestinal perfusion technique was used in the same subjects after ingestion on two consecutive days of 18 g lactose in yoghurt and heated yoghurt. Significantly less lactose was recovered from the terminal ileum after yoghurt than after heated yoghurt meals: 1740 (SE 260) v. 2825 (SE 461) mg (P < 0.05), and approximately one-fifth of the lactase activity contained in yoghurt reached the terminal ileum. These findings indicate that more than 90% of the lactose in yoghurt is digested in the small intestine of lactase-deficient subjects and suggest that both the lactase activity contained in the viable starter culture and a slow oro–caecal transit time are responsible for this excellent absorption.