Effects of Omega-3 Fatty Acid Supplementation on Glucose Control and Lipid Levels in Type 2 Diabetes: A Meta-Analysis

PLoS One. 2015 Oct 2;10(10):e0139565. doi: 10.1371/journal.pone.0139565. eCollection 2015.


Background: Many studies assessed the impact of marine omega-3 fatty acids on glycemic homeostasis and lipid profiles in patients with type 2 diabetes (T2DM), but reported controversial results. Our goal was to systematically evaluate the effects of omega-3 on glucose control and lipid levels.

Methods: Medline, Pubmed, Cochrane Library, Embase, the National Research Register, and SIGLE were searched to identify eligible randomized clinical trials (RCTs). Extracted data from RCTs were analyzed using STATA 11.0 statistical software with fixed or random effects model. Effect sizes were presented as weighted mean differences (WMD) with 95% confidence intervals (95% CI). Heterogeneity was assessed using the Chi-square test with significance level set at p < 0.1.

Results: 20 RCT trials were included into this meta-analysis. Among patients with omega-3 supplementation, triglyceride (TG) levels were significantly decreased by 0.24 mmol/L. No marked change in total cholesterol (TC), HbA1c, fasting plasma glucose, postprandial plasma glucose, BMI or body weight was observed. High ratio of EPA/DHA contributed to a greater decreasing tendency in plasma insulin, HbAc1, TC, TG, and BMI measures, although no statistical significance was identified (except TG). FPG levels were increased by 0.42 mmol/L in Asians. No evidence of publication bias was observed in this meta-analysis.

Conclusions: The ratio of EPA/DHA and early intervention with omega 3 fatty acids may affect their effects on glucose control and lipid levels, which may serve as a dietary reference for clinicians or nutritionists who manage diabetic patients.

Publication types

  • Meta-Analysis

MeSH terms

  • Adolescent
  • Adult
  • Blood Glucose / drug effects*
  • Cholesterol / metabolism*
  • Diabetes Mellitus, Type 2 / blood*
  • Diabetes Mellitus, Type 2 / drug therapy*
  • Diabetes Mellitus, Type 2 / metabolism
  • Dietary Supplements
  • Fatty Acids, Omega-3 / administration & dosage*
  • Female
  • Humans
  • Insulin / blood
  • Lipids / blood*
  • Male
  • Middle Aged
  • Randomized Controlled Trials as Topic
  • Young Adult


  • Blood Glucose
  • Fatty Acids, Omega-3
  • Insulin
  • Lipids
  • Cholesterol

Grant support

This work was supported by a grant from National Natural Science Foundation of China (81100581 to S. Shao) and by a grant from China International Medical Foundation (CIMF) - novo nordisk China β Academy Funding (20110059 to S. Shao). S. Shao is in charge of these two grants.