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

<div><p>Background</p><p>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.</p><p>Methods</p><p>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 <i>p</i> < 0.1.</p><p>Results</p><p>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.</p><p>Conclusions</p><p>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.</p></div

Effects of omega 3 fatty acids on BMI (A), weight (B), FPG (C), PPG (D), HbA1c (E), INS (F), TG (G), and TC (H).

<p>Note: BMI, body mass index; FPG, fast plasma glucose; PPG, postprandial glucose; HbA1c, glycosylated hemoglobin; INS, insulin; TG, Triglyceride; TC, total cholesterol; WMD, weighted mean difference.</p

Omega-3 versus placebo (subgroups EPA/DHA).

<p>Notes: BMI, body mass index; FPG, fast plasma glucose; PPG, postprandial glucose; HbA1c, glycosylated hemoglobin; INS, insulin; TG, Triglyceride; TC, total cholesterol; WMD, weighted mean difference; IV, inverse variance; D+L, DerSimonian & Laird;-, not available.</p><p>Omega-3 versus placebo (subgroups EPA/DHA).</p

Omega-3 versus placebo (subgroups Ethnicity).

<p>Notes: BMI, body mass index; FPG, fast plasma glucose; PPG, postprandial glucose; HbA1c, glycosylated hemoglobin; INS, insulin; TG, Triglyceride; TC, total cholesterol; WMD, weighted mean difference; IV, inverse variance; D+L, DerSimonian & Laird;-, not available.</p><p>Omega-3 versus placebo (subgroups Ethnicity).</p

Accuracy of different prediction methods of insertional RNA editing sites in <i>Didymium</i>.

<p>Each graph shows the percentage of editing sites which are correctly predicted, predicted by one, two, or at least three positions away from the experimentally known correct editing site. (a) shows results for all 15 genes studied, (b) for the more conserved genes, and (c) for the less conserved genes.</p

Omega-3 versus placebo (subgroups study duration).

<p>Notes: BMI, body mass index; FPG, fast plasma glucose; PPG, postprandial glucose; HbA1c, glycosylated hemoglobin; INS, insulin; TG, Triglyceride; TC, total cholesterol; WMD, weighted mean difference; IV, inverse variance; D+L, DerSimonian & Laird;-, not available.</p><p>Omega-3 versus placebo (subgroups study duration).</p

Background frequencies for conservation between <i>Physarum</i> and <i>Didymium</i>.

<p>Background frequencies for conservation between <i>Physarum</i> and <i>Didymium</i>.</p

Number of C insertional editing sites shared by <i>Physarum</i> and <i>Didymium</i>.

<p>Number of C insertional editing sites shared by <i>Physarum</i> and <i>Didymium</i>.</p

Omega-3 versus placebo (subgroups DHA dosage).

<p>Notes: BMI, body mass index; FPG, fast plasma glucose; PPG, postprandial glucose; HbA1c, glycosylated hemoglobin; INS, insulin; TG, Triglyceride; TC, total cholesterol; WMD, weighted mean difference; IV, inverse variance; D+L, DerSimonian & Laird;-, not available.</p><p>Omega-3 versus placebo (subgroups DHA dosage).</p

Comparison of (a) overall conservation and (b) codon bias for real and predicted mRNA sequences.

<p>The data is close to the diagonal in both cases indicating that predicted sequences can be used to estimate these quanitities in cases where the true sequences are not known.</p