Background and aim: The gut bacterial flora, different in obese vs lean subjects (fewer Bacterioides than Firmicutes), promotes fermentation of otherwise indigestible nutrients, such as polysaccharides, enhancing energy intake and favouring the build-up and excretion of H2 (DiBaise et al, 2008). Moreover prevalent dietary intakes may affect the gut microbiota composition (O’Keefe, 2008). To investigate in obese subjects the relationships between prevalent nutrient intakes and H2 excretion by means of Lactulose Breath Test (LBT). Material and methods: Fifty obese patients (8 M/42 F; age 19–70 years; BMI 39.1±6.3 kg/m2) were admitted to the study under their informed consent. Anthropometric and laboratory data were collected from each patient at admission. LBT was performed to each patient and to a group of ten healthy normal weight subjects (age 26-65; 6F/4M). In 12 h overnight fasted subjects, end-expiratory breath samples were collected at 0, 30, 60, 90, 120 min after an oral load of Lactulose, 10 g in water 250 ml. Samples were measured as H2 ppm with the Gastrolyzer® (Bedfont Scientific Ltd, UK). Nutrient intakes, determined by detailed questioning, were compared with the recommended dietary allowances (RDA) for the Italian population. Excessive intake was > the median value of each nutrient in obese group. Statistical analysis was performed with PASW 18.0 software; significance for p<0.05. Results: LBT showed H2 concentrations at 60 min above 20 ppm (range 0-143) in 32% of the obese subjects. Healthy controls were negative. In obese group the majority of macronutrients were significantly higher than RDA except for simple carbohydrates. In obese subjects logistic regression showed that H2 >20-ppm at 60 min was associated with excessive intakes of animal protein (>33g; OR 2.79; 95%CI=0.2-35.8) and carbohydrates (>389g; OR 2.71; 95%CI=0.11-66.2). Conclusions: In obese subjects an increased hydrogen excretion is observed and it is associated with prevalent dietary intakes (animal proteins and carbohydrates). We suggest that the inadequate dietary habit may affect the gut bacterial flora composition.
THE INCREASE OF HYDROGEN EXCRETION IN OBESE SUBJECTS IS ASSOCIATED WITH EXCESSIVE INTAKE OF PREVALENT NUTRIENTS
RICCI, Giorgio;CANDUCCI, Edgardo;ALVISI, Vittorio
2011
Abstract
Background and aim: The gut bacterial flora, different in obese vs lean subjects (fewer Bacterioides than Firmicutes), promotes fermentation of otherwise indigestible nutrients, such as polysaccharides, enhancing energy intake and favouring the build-up and excretion of H2 (DiBaise et al, 2008). Moreover prevalent dietary intakes may affect the gut microbiota composition (O’Keefe, 2008). To investigate in obese subjects the relationships between prevalent nutrient intakes and H2 excretion by means of Lactulose Breath Test (LBT). Material and methods: Fifty obese patients (8 M/42 F; age 19–70 years; BMI 39.1±6.3 kg/m2) were admitted to the study under their informed consent. Anthropometric and laboratory data were collected from each patient at admission. LBT was performed to each patient and to a group of ten healthy normal weight subjects (age 26-65; 6F/4M). In 12 h overnight fasted subjects, end-expiratory breath samples were collected at 0, 30, 60, 90, 120 min after an oral load of Lactulose, 10 g in water 250 ml. Samples were measured as H2 ppm with the Gastrolyzer® (Bedfont Scientific Ltd, UK). Nutrient intakes, determined by detailed questioning, were compared with the recommended dietary allowances (RDA) for the Italian population. Excessive intake was > the median value of each nutrient in obese group. Statistical analysis was performed with PASW 18.0 software; significance for p<0.05. Results: LBT showed H2 concentrations at 60 min above 20 ppm (range 0-143) in 32% of the obese subjects. Healthy controls were negative. In obese group the majority of macronutrients were significantly higher than RDA except for simple carbohydrates. In obese subjects logistic regression showed that H2 >20-ppm at 60 min was associated with excessive intakes of animal protein (>33g; OR 2.79; 95%CI=0.2-35.8) and carbohydrates (>389g; OR 2.71; 95%CI=0.11-66.2). Conclusions: In obese subjects an increased hydrogen excretion is observed and it is associated with prevalent dietary intakes (animal proteins and carbohydrates). We suggest that the inadequate dietary habit may affect the gut bacterial flora composition.I documenti in SFERA sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
