Journal Article

The Influence of Dietary Protein Intake on Mammalian Tryptophan and Phenolic Metabolites

Verbeke, Kristin, Verweij, Vivienne, Masereeuw, Rosalinde, Jansen, Jitske, Windey, Karen, Poesen, Ruben, Meijers, Björn, van den Broek, Petra H., Mutsaers, Henricus A. M., Evenepoel, Pieter, Augustijns, Patrick, Kuypers, Dirk

2015

Overview

Although there has been increasing interest in the use of high protein diets, little is known about dietary protein related changes in the mammalian metabolome. We investigated the influence of protein intake on selected tryptophan and phenolic compounds, derived from both endogenous and colonic microbial metabolism. Furthermore, potential inter-species metabolic differences were studied. For this purpose, 29 healthy subjects were allocated to a high (n = 14) or low protein diet (n = 15) for 2 weeks. In addition, 20 wild-type FVB mice were randomized to a high protein or control diet for 21 days. Plasma and urine samples were analyzed with liquid chromatography-mass spectrometry for measurement of tryptophan and phenolic metabolites. In human subjects, we observed significant changes in plasma level and urinary excretion of indoxyl sulfate (P 0.004 and P 0.001), and in urinary excretion of indoxyl glucuronide (P 0.01), kynurenic acid (P 0.006) and quinolinic acid (P 0.02). In mice, significant differences were noted in plasma tryptophan (P 0.03), indole-3-acetic acid (P 0.02), p-cresyl glucuronide (P 0.03), phenyl sulfate (P 0.004) and phenylacetic acid (P 0.01). Thus, dietary protein intake affects plasma levels and generation of various mammalian metabolites, suggesting an influence on both endogenous and colonic microbial metabolism. Metabolite changes are dissimilar between human subjects and mice, pointing to inter-species metabolic differences with respect to protein intake.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Acetic acid / Adult / Analysis / Animals / Bowel disease / Cardiovascular disease / Chromatography / Clinical medicine / Diabetes / Diet / Dietary intake / Dietary protein / Dietary Proteins - pharmacology / Eating - physiology / Excretion / Feces / Female / Fermentation / Food science / Health aspects / High protein diet / Hospitals / Humans / Immunology / Indoleacetic acid / Influence / Kidney diseases / Kynurenic acid / Liquid chromatography / Low protein diet / Male / Mammals / Mass spectrometry / Mass spectroscopy / Metabolism / Metabolites / Mice / Microorganisms / Nephrology / Nutrient deficiency / Nutrition research / Pediatrics / Pharmaceuticals / Pharmacology / Phenolic compounds / Phenols / Phenols - blood / Phenols - metabolism / Phenols - urine / Phenylacetic acid / Physiology / Pilot Projects / Plasma levels / Proteins / Quinolinic acid / Sulfates / Toxicology / Tryptophan / Tryptophan - blood / Tryptophan - metabolism / Tryptophan - urine / Urine / Young Adult