Skip to Content
Merck
  • A whole-grain-rich diet reduces urinary excretion of markers of protein catabolism and gut microbiota metabolism in healthy men after one week.

A whole-grain-rich diet reduces urinary excretion of markers of protein catabolism and gut microbiota metabolism in healthy men after one week.

The Journal of nutrition (2013-04-26)
Alastair B Ross, Emma Pere-Trépat, Ivan Montoliu, Francois-Pierre J Martin, Sebastiano Collino, Sofia Moco, Jean-Philippe Godin, Marilyn Cléroux, Philippe A Guy, Isabelle Breton, Rodrigo Bibiloni, Anita Thorimbert, Isabelle Tavazzi, Lionel Tornier, Aude Bebuis, Stephen J Bruce, Maurice Beaumont, Laurent-Bernard Fay, Sunil Kochhar
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.

MATERIALS
Product Number
Brand
Product Description

Millipore
Urea solution, suitable for microbiology, 40% in H2O
Sigma-Aldrich
Urea-12C, 99.9 atom % 12C
Sigma-Aldrich
Urea solution, BioUltra, ~8 M in H2O
Sigma-Aldrich
Urea solution, 40 % (w/v) in H2O
Sigma-Aldrich
Nicotinuric acid
Sigma-Aldrich
Trimethyl phosphonoacetate, 98%
Sigma-Aldrich
Urea, BioUltra, for molecular biology, 99% (T)
Sigma-Aldrich
Urea, puriss., meets analytical specification of Ph. Eur., BP, USP, 99.0-100.5%, 99.0-101.0% (calc. on dry substance)
Sigma-Aldrich
Urea, suitable for electrophoresis
Sigma-Aldrich
Urea, meets USP testing specifications
Sigma-Aldrich
Urea, BioXtra, pH 7.5-9.5 (20 °C, 5 M in H2O)
Sigma-Aldrich
Urea, ReagentPlus®, ≥99.5%, pellets
Sigma-Aldrich
Urea, ACS reagent, 99.0-100.5%
Sigma-Aldrich
Urea, powder, BioReagent, for molecular biology, suitable for cell culture
Sigma-Aldrich
L-Carnitine inner salt, synthetic, ≥98%
Levocarnitine, European Pharmacopoeia (EP) Reference Standard
Urea, European Pharmacopoeia (EP) Reference Standard
Supelco
Urea, 8 M (after reconstitution with 16 mL high purity water)
Sigma-Aldrich
Urea, puriss. p.a., ACS reagent, reag. Ph. Eur., ≥99%