Effect of omega-3 supplementation on neuropathy in type 1 diabetes: A 12-month pilot trial

OBJECTIVE:To test the hypothesis that 12 months of seal oil omega-3 polyunsaturated fatty acids (ω-3 PUFA) supplementation will stop the known progression of diabetic sensorimotor polyneuropathy (DSP) in type 1 diabetes mellitus (T1DM). METHODS:Individuals with T1DM and evidence of DSP as determined by a Toronto Clinical Neuropathy Score ≥1 were recruited to participate in a single-arm, open-label trial of seal oil ω-3 PUFA supplementation (10 mL·d; 750 mg eicosapentaenoic acid, 560 mg docosapentaenoic acid, and 1,020 mg docosahexaenoic acid) for 1 year. The primary outcome was the 1-year change in corneal nerve fiber length (CNFL) measured by in vivo corneal confocal microscopy, with sensory and nerve conduction measures as secondary outcomes. RESULTS:Forty participants (53% female), aged 48 ± 14 years, body mass index 28.1 ± 5.8 with diabetes duration of 27 ± 18 years, were enrolled. At baseline, 23 participants had clinical DSP and 17 did not. Baseline CNFL was 8.3 ± 2.9 mm/mm and increased 29% to 10.1 ± 3.7 mm/mm (p = 0.002) after 12 months of supplementation. There was no change in nerve conduction or sensory function. CONCLUSIONS:Twelve months of ω-3 supplementation was associated with increase in CNFL in T1DM. CLINICALTRIALS.GOVIDENTIFIER:NCT02034266. CLASSIFICATION OF EVIDENCE:This study provides Class IV evidence that for patients with T1DM and evidence of DSP, 12 months of seal oil omega-3 supplementation increases CNFL.