Dysbiosis of the faecal microbiota in patients with Crohn's disease and their unaffected relatives

Background and aims A general dysbiosis of the intestinal microbiota has been established in patients with Crohn's disease (CD), but a systematic characterisation of this dysbiosis is lacking. Therefore the composition of the predominant faecal microbiota of patients with CD was studied in comparison with the predominant composition in unaffected controls. Whether dysbiosis is present in relatives of patients CD was also examined. Methods Focusing on families with at least three members affected with CD, faecal samples of 68 patients with CD, 84 of their unaffected relatives and 55 matched controls were subjected to community fingerprinting of the predominant microbiota using denaturing gradient gel electrophoresis (DGGE). To analyse the DGGE profiles, BioNumerics software and non-parametric statistical analyses (SPSS V. 17.0) were used. Observed differences in the predominant microbiota were subsequently confirmed and quantified with real-time PCR. Results Five bacterial species characterised dysbiosis in CD, namely a decrease in Dialister invisus (p = 0.04), an uncharacterised species of Clostridium cluster XIVa (p = 0.03), Faecalibacterium prausnitzii (p<1.3x10(-5)) and Bifidobacterium adolescentis (p = 5.4x10(-6)), and an increase in Ruminococcus gnavus (p = 2.1x10(-7)). Unaffected relatives of patients with CD had less Collinsella aerofaciens (p = 0.004) and a member of the Escherichia coli-Shigella group (p = 0.01) and more Ruminococcus torques (p = 0.02) in their predominant microbiota as compared with healthy subjects. Conclusion Unaffected relatives of patients with CD have a different composition of their microbiota compared with healthy controls. This dysbiosis is not characterised by lack of butyrate producing-bacteria as observed in CD but suggests a role for microorganisms with mucin degradation capacity

Systemic availability and metabolism of colonic-derived short-chain fatty acids in healthy subjects: a stable isotope study

The short-chain fatty acids (SCFAs), acetate, propionate and butyrate, are bacterial metabolites that mediate the interaction between the diet, the microbiota and the host. In the present study, the systemic availability of SCFAs and their incorporation into biologically relevant molecules was quantified. Known amounts of 13C-labelled acetate, propionate and butyrate were introduced in the colon of 12 healthy subjects using colon delivery capsules and plasma levels of 13C-SCFAs 13C-glucose, 13C-cholesterol and 13C-fatty acids were measured. The butyrate-producing capacity of the intestinal microbiota was also quantified. Systemic availability of colonic-administered acetate, propionate and butyrate was 36%, 9% and 2%, respectively. Conversion of acetate into butyrate (24%) was the most prevalent interconversion by the colonic microbiota and was not related to the butyrate-producing capacity in the faecal samples. Less than 1% of administered acetate was incorporated into cholesterol and &lt;15% in fatty acids. On average, 6% of colonic propionate was incorporated into glucose. The SCFAs were mainly excreted via the lungs after oxidation to 13CO2, whereas less than 0.05% of the SCFAs were excreted into urine. These results will allow future evaluation and quantification of SCFA production from 13C-labelled fibres in the human colon by measurement of 13C-labelled SCFA concentrations in blood

Biomarkers to Study the in vivo Efficacy of Pre- and/or Probiotics on the Colonic Fate of Ammonia and P-cresol in Healthy Volunteers

status: publishe

Microbial biochemical processes critical to human health

edition: 1ststatus: publishe

Low-Residue and Low-Fiber Diets in Gastrointestinal Disease Management

Recently, low-residue diets were removed from the American Academy of Nutrition and Dietetics' Nutrition Care Manual due to the lack of a scientifically accepted quantitative definition and the unavailability of a method to estimate the amount of food residue produced. This narrative review focuses on defining the similarities and/or discrepancies between low-residue and low-fiber diets and on the diagnostic and therapeutic values of these diets in gastrointestinal disease management. Diagnostically, a low-fiber/low-residue diet is used in bowel preparation. A bowel preparation is a cleansing of the intestines of fecal matter and secretions conducted before a diagnostic procedure. Therapeutically, a low-fiber/low-residue diet is part of the treatment of acute relapses in different bowel diseases. The available evidence on low-residue and low-fiber diets is summarized. The main findings showed that within human disease research, the terms "low residue" and "low fiber" are used interchangeably, and information related to the quantity of residue in the diet usually refers to the amount of fiber. Low-fiber/low-residue diets are further explored in both diagnostic and therapeutic situations. On the basis of this literature review, the authors suggest redefining a low-residue diet as a low-fiber diet and to quantitatively define a low-fiber diet as a diet with a maximum of 10 g fiber/d. A low-fiber diet instead of a low-residue diet is recommended as a diagnostic value or as specific therapy for gastrointestinal conditions.status: publishe

Does the biomarker 15N-lactose ureide allow to estimate the site of fermentation of resistant starch?

We evaluated the effect of resistant starch (RS) and resistant starch with wheat bran (RS+WB) on the colonic ammonia metabolism in healthy volunteers using the biomarker (15)N-lactose ureide ((15)N-LU). Particularly, it was investigated whether this biomarker allowed to estimate differences in the site of fermentation. Ten volunteers were included in a placebo-controlled crossover study. They consumed in random order 2 x 15 g RS/day for 2 weeks and placebo for 2 weeks separated by 2 weeks wash-out. At baseline, on the first day of each intake period and after each intake period, they consumed a (15)N-labelled test meal and collected all urine in different fractions for 48 h. In ten other volunteers, the effect of 2 x 15 g RS/day and of 2 x 15 g RS + 2 x 6 g WB was compared. These volunteers collected urine and feces for 72 h. (15)N-content of urine and feces was measured using combustion-isotope ratio mass spectrometry. RS exerted a significant decrease in cumulative urinary (15)N-excretion which was different from placebo. The effect was most pronounced in the 6-24 h urine fraction which suggest fermentation in the proximal colon. The effect of RS+WB on cumulative urinary (15)N-excretion was not significantly different from the effect of RS. A less pronounced decrease in the 6-24 h fraction was observed suggesting less fermentation in the proximal colon whereas no indications for more distal fermentation were observed. Since about 80% of the cumulative urinary (15)N was recovered within 24 h, it was concluded that the biomarker (15)N-LU was useful to monitor processes in the proximal colon rather than in the distal colon.status: publishe

Wat is het nu weer, restenarm of vezelarm dieet?

status: publishe