Effects of n-3 fatty acids on macro- and microvascular function in subjects with type 2 diabetes mellitus.

Randomized, placebo-controlled crossover trial in adults with type 2 diabetes mellitus in Bochum, Germany. The active n-3 fatty acid sequence included 17 participants at start and 16 completers; the broader study enrolled 34 adults aged 37 to 70 years without major cardiovascular disease or advanced diabetic complications.

Participants received 2 oral gel capsules daily for 6 weeks of omega-3 acid ethyl esters (Omacor). Each capsule contained 460 mg EPA ethyl ester and 380 mg DHA ethyl ester plus 60 mg other n-3 fatty acids, for a daily total of about 1800 mg n-3 fatty acids; vitamin E 8 mg/day was included in the capsules.

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.

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. Dietary intake and background therapy were not materially changed during the study, but detailed diet assessment was not reported. The crossover design and brief 6-week exposure limit inference about long-term vascular or clinical outcomes.