Mitchell SMMcKenzie EJMitchell CJMilan AMZeng ND'Souza RFRamzan FSharma PRettedal EKnowles SORoy NCSjödin AWagner K-HO'Sullivan JMCameron-Smith D2024-10-302024-10-302020-07-02Mitchell SM, McKenzie EJ, Mitchell CJ, Milan AM, Zeng N, D'Souza RF, Ramzan F, Sharma P, Rettedal E, Knowles SO, Roy NC, Sjödin A, Wagner K-H, O'Sullivan JM, Cameron-Smith D. (2020). A period of 10 weeks of increased protein consumption does not alter faecal microbiota or volatile metabolites in healthy older men: a randomised controlled trial.. J Nutr Sci. 9. (pp. e25-).2048-6790https://mro.massey.ac.nz/handle/10179/71875Diet has a major influence on the composition and metabolic output of the gut microbiome. Higher-protein diets are often recommended for older consumers; however, the effect of high-protein diets on the gut microbiota and faecal volatile organic compounds (VOC) of elderly participants is unknown. The purpose of the study was to establish if the faecal microbiota composition and VOC in older men are different after a diet containing the recommended dietary intake (RDA) of protein compared with a diet containing twice the RDA (2RDA). Healthy males (74⋅2 (sd 3⋅6) years; n 28) were randomised to consume the RDA of protein (0⋅8 g protein/kg body weight per d) or 2RDA, for 10 weeks. Dietary protein was provided via whole foods rather than supplementation or fortification. The diets were matched for dietary fibre from fruit and vegetables. Faecal samples were collected pre- and post-intervention for microbiota profiling by 16S ribosomal RNA amplicon sequencing and VOC analysis by head space/solid-phase microextraction/GC-MS. After correcting for multiple comparisons, no significant differences in the abundance of faecal microbiota or VOC associated with protein fermentation were evident between the RDA and 2RDA diets. Therefore, in the present study, a twofold difference in dietary protein intake did not alter gut microbiota or VOC indicative of altered protein fermentation.(c) 2020 The Author/sCC BY 4.0https://creativecommons.org/licenses/by/4.0/16S amplicon sequencing16S rRNA, 16S ribosomal RNA2RDA, diet containing twice the RDA of proteinAMDIS, Automated Mass Spectral Deconvolution and Identification SystemBCFA, branched-chain fatty acidFermentationHS/SPME/GCMS, head space/solid-phase microextraction/GC-MSMaAsLin, Multivariate Association with Linear ModelMicrobiomeRDA, diet containing the RDA of proteinRecommended dietary intakeVOC, volatile organic compoundVolatile organic compoundsAgedDiet, High-ProteinDietary ProteinsFecesGastrointestinal MicrobiomeHumansMaleMicrobiotaNutritional RequirementsTreatment OutcomeVolatile Organic CompoundsJournal article10.1017/jns.2020.152048-6790journal-articlee25-https://www.ncbi.nlm.nih.gov/pubmed/32742642e25S2048679020000154