Fish oil supplementation improves endothelial function in normoglycemic offspring of patients with type 2 diabetes

Abstract

Objective: Offspring of patients with type 2 diabetes (OPDs) exhibits endothelial dysfunction (ED) associated with a chronic inflammatory state. N-3 polyunsaturated fatty acids (n-3 PUFA) may have antioxidant and anti-inflammatory properties that are beneficial for cardiovascular and metabolic health. Therefore, in the present study, we tested the hypothesis that dietary supplementation with fish oil rich in n-3 PUFA may improve ED in otherwise healthy OPDs.

Methods and design: A double-blind, placebo-controlled trial was conducted with 50 OPDs. Participants were randomized to treatment with either placebo or n-3 PUFA (2g/day) for 12 weeks. Before and after treatment we evaluated endothelial function (using flow-mediated dilation (FMD) of the brachial artery), circulating inflammatory markers (adiponectin, TNF-alpha, and high sensitivity-CRP), and insulin resistance (QUICKI).

Results: No significant changes were observed in study outcomes in subjects treated with placebo. By contrast, when compared with baseline values, subjects treated with n-3 PUFA had significant improvement in FMD (9.1+/-5.8% vs. 11.7+/-4.4%, p=0.02) that was accompanied by decreased plasma triglycerides (117+/-73mg/dl vs. 86+/-44mg/dl, p=0.001) and TNF-alpha levels (8.9+/-2.3pg/ml vs. 6.8+/-2.7pg/ml, p=0.001), and a trend towards increased plasma adiponectin levels (7.8+/-4.5microg/ml vs. 9.5+/-5.1microg/ml, p=0.09). When data were analyzed by multiple regression analysis, decreased TNF-alpha after treatment with n-3 PUFA predicted increased FMD.

Conclusion: Dietary supplementation with n-3 PUFA significantly improved endothelial function and reduced pro-inflammatory markers in OPDs. Thus, fish oil consumption may have beneficial cardiovascular and metabolic health effects in otherwise healthy subjects predisposed to diabetes and its vascular complications.

Conflict of interest statement

Conflict of interest

No conflict of interest, potentially prejudicing the impartiality of the research reported, concerns this manuscript.

Figures

Fig. 1

Change in flow mediated dilation (FMD) in OPDs after n-3 PUFA or placebo treatment. Panel A: baseline FMD (hatched bars) and FMD after 12 weeks (dark grey bars) of n-3 PUFA or placebo. Panel B: white bars represent baseline FMD; grey bars represents FMD after 12 weeks of n-3 PUFA. Panel C: white bars represent baseline FMD; grey bars represents FMD after 12 weeks of placebo. NGT: normal glucose tolerance; IGT: impaired glucose tolerance. Bar graphs show data as mean ± S.E.M.

Fig. 2

Correlations between changes in FMD and changes in triglyceride or TNF-α levels after 12 weeks of therapy with n-3 PUFA.