Effects of n-3 fatty acids on macro- and microvascular function in subjects with type 2 diabetes mellitus.
What this study found
Six weeks of purified omega-3 fatty acids improved postprandial vascular function compared with placebo, while fasting vascular function was unchanged. The time-by-treatment interaction favored n-3 fatty acids for brachial FMD (P = 0.03) and microvascular reactive hyperemia (P = 0.04). Postprandial FMD declined less with n-3 fatty acids, with FMD-AUC 22.31 ± 1.83 versus 28.24 ± 2.20 with placebo, and the postprandial RH response was also better preserved. No adverse events were reported.
- Study & population
- Randomized, placebo-controlled crossover trial in adults with type 2 diabetes mellitus in Bochum, Germany.
- Intervention
- Participants received 2 oral gel capsules daily for 6 weeks of omega-3 acid ethyl esters (Omacor).
- Key limitation
- The trial was small, short term, and conducted in a selected group of adults with type 2 diabetes without major cardiovascular disease or advanced complications, which limits generalizability.
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Open PDFOriginal abstract
BACKGROUND Recent evidence supports the protective effects of n-3 (omega-3) fatty acids (n-3 FAs), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), on vascular function. OBJECTIVE We investigated the effects of EPA and DHA on postprandial vascular function in subjects with type 2 diabetes mellitus. DESIGN In a double-blind, placebo-controlled, randomized, crossover manner, 34 subjects with type 2 diabetes mellitus received daily either 2 g purified EPA/DHA (termed n-3 FAs) or olive oil (placebo) for 6 wk. At the end of this period, we measured macrovascular (brachial ultrasound of flow-mediated dilatation; FMD) and microvascular [laser-Doppler measurements of reactive hyperemia (RH) of the hand] function at fasting and 2, 4, and 6 h after a high-fat meal (600 kcal, 21 g protein, 41 g carbohydrates, 40 g fat). RESULTS Fasting vascular function remained unchanged after n-3 FAs and placebo. Postprandial FMD decreased from fasting after placebo, with a maximum decrease (38%) at 4 h-an effect that was significantly reduced (P = 0.03 for time x treatment interaction) by n-3 FA supplementation (maximum decrease in FMD was at 4 h: 13%). RH remained unchanged after placebo, whereas it improved significantly (P = 0.04 for time x treatment interaction) after n-3 FA supplementation (maximum increase was at 2 h: 27%). CONCLUSIONS In subjects with type 2 diabetes mellitus, 6 wk of supplementation with n-3 FAs reduced the postprandial decrease in macrovascular function relative to placebo. Moreover, n-3 FA supplementation improved postprandial microvascular function. These observations suggest a protective vascular effect of n-3 FAs.