Effect of consumption of a ready-to-eat breakfast cereal containing inulinon the intestinal milieu and blood lipids in healthy male volunteers

Objective: To investigate the effect of a breakfast cereal containing inuli n on blood lipids and colonic ecosystem in normolipidemic young men. Setting: Department of Food Science and Microbiology, University of Milan, Italy. Subjects: Twelve healthy male volunteers, age 23.3 +/- 0.5 y, body mass ind ex (BMI) 25.7 +/- 1.2 kg/m(2) (mean +/- s.e.m.). Interventions: Subjects consumed daily, for three periods of four weeks, 50 g of a rice-based ready-to-eat cereal (placebo) and the same cereal contai ning 18% inulin (test) in substitution of their habitual breakfast, then re turned to the habitual diet (wash-out). They followed no other dietary rest rictions. Results: No changes in body weight, dietary habits, faecal and bile acid ou tput, faecal short-chain fatty acid (SCFA) and faecal pH, were observed at the end of each period, whereas plasma total cholesterol and triacylglycero ls significantly decreased at the end of test period by 7.9+/-5.4 (P < 0.05 ) and 21.2+/-7.8% (P < 0.005) respectively. Meal glucose tolerance test (MT T) resulted in the same incremental area under the curve for both cereals ( IAUC test 124 +/- 35; placebo 118 +/- 33 mmol.min/l, ns). Inulin markedly e nhanced breath H-2 excretion (IAUC test 280+/-40; placebo 78+/-26 ppm.h, P < 0.005), as well as faecal concentration of L-lactate. Total facultative a naerobes significantly decreased after test, and bifidobacteria increased a lter correction for total anaerobes (P < 0.05). Changes in blood lipids wer e negatively correlated with bifidobacteria counts and positively with seco ndary bile acid excretion (P < 0.05). Conclusions: Inulin seems to have a lipid lowering potential in normolipide mic men possibly mediated by mechanisms related to colonic fermentation.