Background: The role of omega-3 polyunsaturated fatty acids (n-3PUFA), and the potential impact of n-3PUFA supplementation,
in the treatment and management of type 1 diabetes (T1D) remains unclear and controversial. Therefore,
this study aimed to examine the efficacy of daily high-dose-bolus n-3PUFA supplementation on vascular health,
glycaemic control, and metabolic parameters in subjects with T1D.
Methods: Twenty-seven adults with T1D were recruited to a 6-month randomised, double-blind, placebo-controlled
trial. Subjects received either 3.3 g/day of encapsulated n-3PUFA or encapsulated 3.0 g/day corn oil placebo (PLA) for
6-months, with follow-up at 9-months after 3-month washout. Erythrocyte fatty acid composition was determined
via gas chromatography. Endpoints included inflammation-associated endothelial biomarkers (vascular cell adhesion
molecule-1 [VCAM-1], intercellular adhesion molecule-1 [ICAM-1], E-selectin, P-selectin, pentraxin-3, vascular
endothelial growth factor [VEGF]), and their mediator tumor necrosis factor alpha [TNFα] analysed via immunoassay,
vascular structure (carotid intima-media thickness [CIMT]) and function (brachial artery flow mediated dilation [FMD])
determined via ultrasound technique, blood pressure, glycosylated haemoglobin (HbA1c), fasting plasma glucose
(FPG), and postprandial metabolism.
Results: Twenty subjects completed the trial in full. In the n-3PUFA group, the mean ± SD baseline n-3PUFA index of
4.93 ± 0.94% increased to 7.67 ± 1.86% (P < 0.001) after 3-months, and 8.29 ± 1.45% (P < 0.001) after 6-months. Total
exposure to n-3PUFA over the 6-months (area under the curve) was 14.27 ± 3.05% per month under n-3PUFA, and
9.11 ± 2.74% per month under PLA (P < 0.001). VCAM-1, ICAM-1, E-selectin, P-selectin, pentraxin-3, VEGF, TNFα, CIMT,
FMD, blood pressure, HbA1c, FPG, and postprandial metabolism did not differ between or within groups after treatment
(P > 0.05).