Increasing skeletal muscle carnitine content in older individuals increases whole-body fat oxidation during moderate-intensity exercise
dc.contributor.author | Chee, C | |
dc.contributor.author | Shannon, CE | |
dc.contributor.author | Burns, A | |
dc.contributor.author | Selby, AL | |
dc.contributor.author | Wilkinson, D | |
dc.contributor.author | Smith, K | |
dc.contributor.author | Greenhaff, PL | |
dc.contributor.author | Stephens, FB | |
dc.date.accessioned | 2021-01-26T11:07:44Z | |
dc.date.issued | 2021-01-19 | |
dc.description.abstract | Intramyocellular lipid (IMCL) utilization is impaired in older individuals, and IMCL accumulation is associated with insulin resistance. We hypothesized that increasing muscle total carnitine content in older men would increase fat oxidation and IMCL utilization during exercise, and improve insulin sensitivity. Fourteen healthy older men (69 ± 1 year, BMI 26.5 ± 0.8 kg/m2 ) performed 1 h of cycling at 50% VO2 max and, on a separate occasion, underwent a 60 mU/m2 /min euglycaemic hyperinsulinaemic clamp before and after 25 weeks of daily ingestion of a 220 ml insulinogenic beverage (44.4 g carbohydrate, 13.8 g protein) containing 4.5 g placebo (n = 7) or L-carnitine L-tartrate (n = 7). During supplementation, participants performed twice-weekly cycling for 1 h at 50% VO2 max. Placebo ingestion had no effect on muscle carnitine content or total fat oxidation during exercise at 50% VO2 max. L-carnitine supplementation resulted in a 20% increase in muscle total carnitine content (20.1 ± 1.2 to 23.9 ± 1.7 mmol/kg/dm; p < 0.01) and a 20% increase in total fat oxidation (181.1 ± 15.0 to 220.4 ± 19.6 J/kg lbm/min; p < 0.01), predominantly due to increased IMCL utilization. These changes were associated with increased expression of genes involved in fat metabolism (ACAT1, DGKD & PLIN2; p < 0.05). There was no change in resting insulin-stimulated whole-body or skeletal muscle glucose disposal after supplementation. This is the first study to demonstrate that a carnitine-mediated increase in fat oxidation is achievable in older individuals. This warrants further investigation given reduced lipid turnover is associated with poor metabolic health in older adults. | en_GB |
dc.description.sponsorship | Dunhill Medical Trust | en_GB |
dc.identifier.citation | Article e13303 | en_GB |
dc.identifier.doi | 10.1111/acel.13303 | |
dc.identifier.grantnumber | R211/0711 | en_GB |
dc.identifier.uri | http://hdl.handle.net/10871/124503 | |
dc.language.iso | en | en_GB |
dc.publisher | Wiley / Anatomical Society of Great Britain and Ireland | en_GB |
dc.relation.url | https://www.ncbi.nlm.nih.gov/pubmed/33464721 | en_GB |
dc.rights | © 2021 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. | en_GB |
dc.subject | carnitine | en_GB |
dc.subject | fat oxidation | en_GB |
dc.subject | insulin resistance | en_GB |
dc.subject | intramyocellular lipid | en_GB |
dc.subject | older adults | en_GB |
dc.subject | skeletal muscle | en_GB |
dc.title | Increasing skeletal muscle carnitine content in older individuals increases whole-body fat oxidation during moderate-intensity exercise | en_GB |
dc.type | Article | en_GB |
dc.date.available | 2021-01-26T11:07:44Z | |
exeter.place-of-publication | England | en_GB |
dc.description | This is the final version. Available on open access from Wiley via the DOI in this record | en_GB |
dc.description | Data availability: The data that support the findings of this study are available on request from the corresponding author. The data are not publicly available due to privacy or ethical restrictions. | en_GB |
dc.identifier.eissn | 1474-9726 | |
dc.identifier.journal | Aging Cell | en_GB |
dc.rights.uri | https://creativecommons.org/licenses/by/4.0/ | en_GB |
dcterms.dateAccepted | 2020-12-21 | |
rioxxterms.version | VoR | en_GB |
rioxxterms.licenseref.startdate | 2021-01-19 | |
rioxxterms.type | Journal Article/Review | en_GB |
refterms.dateFCD | 2021-01-26T11:06:32Z | |
refterms.versionFCD | VoR | |
refterms.dateFOA | 2021-01-26T11:07:56Z | |
refterms.panel | C | en_GB |
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Except where otherwise noted, this item's licence is described as © 2021 The Authors. Aging Cell published by the Anatomical Society and John Wiley & Sons Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.