Original Contributions

Subject Category: Nutrition/Obesity

Citation: Clinical and Translational Gastroenterology (2016) 7, e161; doi:10.1038/ctg.2016.20
Published online 7 April 2016

Impact of Dietary Lipids on Colonic Function and Microbiota: An Experimental Approach Involving Orlistat-Induced Fat Malabsorption in Human Volunteers
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Pamela Morales1, Sayaka Fujio2, Paola Navarrete2, Juan A Ugalde3, Fabien Magne4, Catalina Carrasco-Pozo1, Karina Tralma1, MariaPaz Quezada1, Carmen Hurtado5, Natalia Covarrubias5, Jerusa Brignardello2, Daniela Henriquez2 and Martin Gotteland1,2

  1. 1Department of Nutrition, Faculty of Medicine, University of Chile, Santiago, Chile
  2. 2Laboratory of Microbiology and Probiotics, Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago, Chile
  3. 3Center for Genomics and Bioinformatics, Faculty of Sciences, Universidad Mayor, Santiago, Chile
  4. 4Institute of Biomedical Sciences, Faculty of Medicine, Universidad de Chile, Santiago, Chile
  5. 5Gastroentenrology Section, University of Chile Clinical Hospital, University of Chile, Santiago, Chile

Correspondence: Martin Gotteland, PhD, Department of Nutrition, Faculty of Medicine, University of Chile, Independencia, Santiago 1027, Chile. E-mail: mgottela@med.uchile.cl

Received 11 November 2015; Accepted 7 March 2016

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Abstract

OBJECTIVES:

 

High-fat diets alter gut microbiota and barrier function, inducing metabolic endotoxemia and low-grade inflammation. Whether these effects are due to the high dietary lipid content or to the concomitant decrease of carbohydrate intake is unclear. The aim of this study was to determine whether higher amounts of dietary fat reaching the colon (through orlistat administration) affect the colonic ecosystem in healthy volunteers and the effect of the prebiotic oligofructose (OF) in this model.

METHODS:

 

Forty-one healthy young subjects were distributed among four groups: Control (C), Prebiotic (P), Orlistat (O), and Orlistat/Prebiotic (OP). They consumed a fat-standardized diet (60g/day) during Week-1 (baseline) and after 1 week of washout, Week-3. During Week-3, they also received their respective treatment (Orlistat: 2 × 120mg/day, OF: 16g/day, and maltodextrin as placebo). A 72-h stool collection was carried out at the end of Week-1 (T0) and Week-3 (T1). Fecal fat, calprotectin, and short-chain fatty acids (SCFAs) as well as the antioxidant activity of fecal waters (ferric-reducing antioxidant power), fecal microbiota composition (by deep sequencing), and gut permeability (Sucralose/Lactulose/Mannitol test) were determined at these times.

RESULTS:

 

Fecal fat excretion was higher in the O (P=0.0050) and OP (P=0.0069) groups. This event was accompanied, in the O group, by an increased calprotectin content (P=0.047) and a decreased fecal antioxidant activity (P=0.047). However, these alterations did not alter gut barrier function and the changes observed in the composition of the fecal microbiota only affected bacterial populations with low relative abundance (<0.01%); in consequences, fecal SCFA remained mainly unchanged. Part of the colonic alterations induced by orlistat were prevented by OF administration.

CONCLUSIONS:

 

In the context of an equilibrated diet, the acute exposition of the colonic ecosystem to high amounts of dietary lipids is associated with an incremented excretion of fecal calprotectin and pro-oxidant activity of the colonic content, in the absence of significant changes in the microbiota.