Effect of carnosine or β-alanine supplementation on markers of glycemic control and insulin resistance in humans and animals: a systematic review and meta-analysis

Matthews, JJ, Dolan, E, Swinton, PA, Santos, L ORCID logoORCID: https://orcid.org/0000-0002-1915-6780, Artioli, GG, Turner, MD ORCID logoORCID: https://orcid.org/0000-0001-7175-1053, Elliott-Sale, KJ ORCID logoORCID: https://orcid.org/0000-0003-1122-5099 and Sale, C ORCID logoORCID: https://orcid.org/0000-0002-5816-4169, 2021. Effect of carnosine or β-alanine supplementation on markers of glycemic control and insulin resistance in humans and animals: a systematic review and meta-analysis. Advances in Nutrition. ISSN 2156-5376

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Abstract

There is growing evidence that supplementation with carnosine, or its rate-limiting precursor β-alanine, can ameliorate aspects of metabolic dysregulation that occur in diabetes and its related conditions. The purpose of this systematic review and meta-analysis was to evaluate the effect of carnosine or β-alanine supplementation on markers of glycemic control and insulin resistance in humans and animals. We performed a systematic search of 6 electronic databases up to 31 December 2020. Primary outcomes were changes in 1) fasting glucose, 2) glycated hemoglobin (HbA1c), and 3) 2-h glucose following a glucose-tolerance test. A set of additional outcomes included fasting insulin and homeostatic model assessment of β-cell function (HOMA-β) and insulin resistance (HOMA-IR). We assessed risk of bias using the Cochrane risk of bias (RoB) 2.0 (human studies) and the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) RoB (animal studies) tools; and used the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach to assess certainty. We used Bayesian hierarchical random-effects models, with informative priors for human data and noninformative priors for animal data. Inferences were made on posterior samples generated by Hamiltonian Markov Chain Monte Carlo using 90% credible intervals (90% CrI) and calculated probabilities. Twenty studies (n = 4 human, n = 16 rodent) were included, providing data for 2 primary outcomes (fasting glucose and HbA1c) and 3 additional outcomes (fasting insulin, HOMA-β, and HOMA-IR). The model provides evidence that supplementation decreases fasting glucose [humans: mean difference (MD)0.5 = –0.95 mmol · L–1 (90% CrI: –2.1, 0.08); rodent: MD0.5 = –2.26 mmol · L–1 (90% CrI: –4.03, –0.44)], HbA1c [humans: MD0.5 = –0.91% (90% CrI: –1.46, –0.39); rodents: MD0.5 = –1.05% (90% CrI: –1.64, –0.52)], HOMA-IR [humans: standardized mean difference (SMD)0.5 = –0.41 (90% CrI: –0.82, –0.07); rodents: SMD0.5 = –0.63 (90% CrI: –1.98, 0.65)], and fasting insulin [humans: SMD0.5 = –0.41 (90% CrI: –0.77, –0.07)]. GRADE assessment showed our certainty in the effect estimate of each outcome to be moderate (human outcomes) or very low (rodent outcomes). Supplementation with carnosine or β-alanine may reduce fasting glucose, HbA1c, and HOMA-IR in humans and rodents, and fasting insulin in humans; both compounds show potential as therapeutics to improve glycemic control and insulin resistance.

Item Type: Journal article
Alternative Title: Carnosine, glycemic control, and insulin resistance
Publication Title: Advances in Nutrition
Creators: Matthews, J.J., Dolan, E., Swinton, P.A., Santos, L., Artioli, G.G., Turner, M.D., Elliott-Sale, K.J. and Sale, C.
Publisher: Oxford University Press
Date: 31 July 2021
ISSN: 2156-5376
Identifiers:
Number
Type
10.1093/advances/nmab087
DOI
1465461
Other
Rights: © the author(s) 2021. Published by Oxford University Press on behalf of the American Society for Nutrition. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
Divisions: Schools > School of Science and Technology
Record created by: Jonathan Gallacher
Date Added: 02 Sep 2021 08:38
Last Modified: 02 Sep 2021 08:38
URI: https://irep.ntu.ac.uk/id/eprint/44101

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