title: A whole-grain-rich diet reduces urinary excretion of markers of protein catabolism and gut microbiota metabolism in healthy men after one week.
abstract: Epidemiological studies consistently find that diets rich in whole-grain (WG) cereals lead to decreased risk of disease compared with refined grain (RG)-based diets. Aside from a greater amount of fiber and micronutrients, possible mechanisms for why WGs may be beneficial for health remain speculative. In an exploratory, randomized, researcher-blinded, crossover trial, we measured metabolic profile differences between healthy participants eating a diet based on WGs compared with a diet based on RGs. Seventeen healthy adult participants (11 female, 6 male) consumed a controlled diet based on either WG-rich or RG-rich foods for 2 wk, followed by the other diet after a 5-wk washout period. Both diets were the same except for the use of WG (150 g/d) or RG foods. The metabolic profiles of plasma, urine, and fecal water were measured using (1)H-nuclear magnetic resonance spectroscopy and gas chromatography-mass spectrometry (plasma only). After 1 wk of intervention, the WG diet led to decreases in urinary excretion of metabolites related to protein catabolism (urea, methylguanadine), lipid (carnitine and acylcarnitines) and gut microbial (4-hydroxyphenylacetate, trimethylacetate, dimethylacetate) metabolism in men compared with the same time point during the RG intervention. There were no differences between the interventions after 2 wk. Urinary urea, carnitine, and acylcarnitine were lower at wk 1 of the WG intervention relative to the RG intervention in all participants. Fecal water short-chain fatty acids acetate and butyrate were relatively greater after the WG diet compared to the RG diet. Although based on a small population and for a short time period, these observations suggest that a WG diet may affect protein metabolism.
authors.affiliation: Nestlé Research Centre, Vers chez les Blanc, Lausanne, Switzerland. Alastair.Ross@chalmers.se
authors.forename: Alastair B
authors.initials: AB
authors.lastname: Ross
authors.forename: Emma
authors.initials: E
authors.lastname: Pere-Trépat
authors.forename: Ivan
authors.initials: I
authors.lastname: Montoliu
authors.forename: Francois-Pierre J
authors.initials: FP
authors.lastname: Martin
authors.forename: Sebastiano
authors.initials: S
authors.lastname: Collino
authors.forename: Sofia
authors.initials: S
authors.lastname: Moco
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Godin
authors.forename: Marilyn
authors.initials: M
authors.lastname: Cléroux
authors.forename: Philippe A
authors.initials: PA
authors.lastname: Guy
authors.forename: Isabelle
authors.initials: I
authors.lastname: Breton
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Bibiloni
authors.forename: Anita
authors.initials: A
authors.lastname: Thorimbert
authors.forename: Isabelle
authors.initials: I
authors.lastname: Tavazzi
authors.forename: Lionel
authors.initials: L
authors.lastname: Tornier
authors.forename: Aude
authors.initials: A
authors.lastname: Bebuis
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Bruce
authors.forename: Maurice
authors.initials: M
authors.lastname: Beaumont
authors.forename: Laurent-Bernard
authors.initials: LB
authors.lastname: Fay
authors.forename: Sunil
authors.initials: S
authors.lastname: Kochhar
mesh_terms: D000085:Acetates / Q000032:analysis; D000328:Adult; D001419:Bacteria / Q000378:metabolism; D015415:Biomarkers / Q000097:blood / Q000652:urine*; D002331:Carnitine / Q000652:urine; D018592:Cross-Over Studies; D004032:Diet; D004043:Dietary Fiber; D002523:Edible Grain; D004734:Energy Metabolism; D005243:Feces / Q000737:chemistry; D005260:Female; D005511:Food Handling; D008401:Gas Chromatography-Mass Spectrometry; D006293:Health Promotion; D006801:Humans; D007422:Intestines / Q000382:microbiology*; D050356:Lipid Metabolism; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D055442:Metabolome; D008744:Methylamines / Q000032:analysis; D008760:Methylguanidine / Q000652:urine; D008875:Middle Aged; D009539:Nicotinic Acids / Q000032:analysis; D010755:Organophosphates / Q000032:analysis; D010648:Phenylacetates / Q000032:analysis; D011506:Proteins / Q000378:metabolism*; D012737:Sex Factors; D014508:Urea / Q000652:urine
chemical_list: D000085:Acetates; D015415:Biomarkers; D004043:Dietary Fiber; D008744:Methylamines; D009539:Nicotinic Acids; D010755:Organophosphates; D010648:Phenylacetates; D011506:Proteins; C026246:4-hydroxyphenylacetate; C038129:trimethylacetyl phosphate; D008760:Methylguanidine; C002477:nicotinuric acid; D014508:Urea; D002331:Carnitine