The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: a systematic review and meta-analysis of randomized controlled clinical trials

Jovanovski, Elena and Li, Dandan and Thanh Ho, Hoang Vi and Djedovic, Vladimir and Ruiz Marques, Any de Castro and Shishtar, Esra and Mejia, Sonia Blanco and Sievenpiper, John L. and de Souza, Russell J. and Duvnjak, Lea and Vuksan, Vladimir (2017) The effect of alpha-linolenic acid on glycemic control in individuals with type 2 diabetes: a systematic review and meta-analysis of randomized controlled clinical trials. Medicine, 96 (21). e6531. ISSN 0025-7974

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BACKGROUND: Polyunsaturated fats (PUFAs) have been shown to reduce type 2 diabetes (T2DM) risk and improve insulin responsiveness in T2DM subjects, but whether the plant sources of omega-3 PUFA (alpha-linolenic acid [ALA]) have an effect on glycemic control requires further investigation. ----- METHODS: The parameters of interest were glycated hemoglobin (HbA1c), fasting blood glucose (FBG), fasting blood insulin (FBI), homeostatic model assessment for insulin resistance (HOMA-IR), fructosamine, and glycated albumin. A comprehensive search was conducted with MEDLINE, Embase, CINAHL, and Cochrane. Eligible studies included randomized controlled trials (RCTs) ≥1 month in duration that compared diets enriched in ALA with usual diets on glycemic parameters. For each study, the risk of bias as well as the study quality was assessed. Using the statistical software RevMan (v5.3), data were pooled using the generic inverse method with random effects model, and final results were expressed as mean differences (MD) with 95% confidence intervals (CI). Heterogeneity was assessed by the Cochran Q statistic and quantified by the I statistic. ----- RESULTS: A total of 8 trials (N = 212) were included in the meta-analysis. Compared to a control diet, a median dose of 4.4 g/day of ALA intake for a median duration of 3 months did not affect HbA1c (%) (MD = -.01; [95%: -.32, .31], P = .96). A median ALA dose of 5.4 g/day did not lower FBG (MD = .07; [95% CI: -.61, .76], P = .84) or FBI (MD = 7.03, [95% CI: -5.84, 19.89], P = .28). Summary effect estimates were generally compromised by considerable and unexplained heterogeneity (I ≥75%). In the subgroup analysis of continuous predictors, a reduction in HbA1c (%) and FBG (mmol/L) was significantly associated with an increased intake of ALA. Further adjustment for Publication Bias using Duval and Tweedie's trim-and-fill analysis provided an adjusted, significant MD of -.25 (95% CI: -.38, -.12; P <.001) for HbA1c (%). ----- CONCLUSIONS: ALA-enriched diets did not affect HbA1c, FBG, or FBI. The scarce number of existing RCTs and the presence of heterogeneity in our meta-analysis limit the ability to make firm conclusions about ALA in T2DM management. The potential for ALA to have dose-dependent effects warrants further research in this area.

Item Type: Article
Additional Information: © 2017 the Author(s). Published by Wolters Kluwer Health, Inc. This is an open access article distributed under the Creative Commons Attribution-No Derivatives License 4.0, which allows for redistribution, commercial and noncommercial, as long as it is passed along unchanged and in whole, with credit to the author.
MeSH: Diabetes Mellitus, Type 2/blood ; Diabetes Mellitus, Type 2/diet therapy ; Humans ; Randomized Controlled Trials as Topic ; alpha-Linolenic Acid/administration & dosage
Departments: Katedra za internu medicinu
Depositing User: Martina Žužak
Status: Published
Jovanovski, ElenaUNSPECIFIED
Djedovic, VladimirUNSPECIFIED
Ruiz Marques, Any de CastroUNSPECIFIED
Mejia, Sonia BlancoUNSPECIFIED
Sievenpiper, John L.UNSPECIFIED
de Souza, Russell J.UNSPECIFIED
Vuksan, VladimirUNSPECIFIED
Date: May 2017
Date Deposited: 02 Mar 2018 09:22
Last Modified: 19 Aug 2020 08:18
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