Researchers from the Krembil Neuroscience Centre in Toronto have found omega-3 supplements derived from seal oil may support early nerve regeneration in patients with type 1 diabetes.
"This study is the first to show that targeted nutritional intervention can stop and reverse small fiber damage," says Vera Bril, MD, principal investigator and head of the division of neurology and medical director of the Ellen Prosserman Centre for Neuromuscular Diseases.
The findings from the single-arm, open-label study were published in the June 2017 issue of Neurology.
Researchers recruited 40 patients with type 1 diabetes, 23 of whom had evidence of diabetic sensorimotor polyneuropathy (DSP) determined using the Toronto Clinical Neuropathy Score. Patients were asked to take twice-daily seal oil omega-3 polyunsaturated fatty acid supplementation (ω-3 PUFA) for 1 year. In vivo corneal confocal microscopy was used to measure corneal nerve fiber length (CNFL), which is typically considered representative of small nerve fiber regeneration in other parts of the body and a biomarker for disease progression.
At the end of the year-long study, investigators found study patients on average had a 29% increase in CNFL (P=0.002), well above the authors’ hypothesized change of 5%.
At baseline, the participants with diagnosed DSP had lower CNFL than those without (7.1 vs. 9.6 mm/mm2, P=0.01). However, at 1 year, CNFL had equalized between the groups (P=0.5). This suggests that the supplements prevented progression of clinical symptoms typically observed in those with DSP.
Subgroup analysis, however, showed that ω-3 PUFA intervention failed to benefit some individuals. CNFL increased by an average of 51% in the 25 participants who responded to the supplements. In contrast, the 11 nonresponders showed a 19% decrease in CNFL.
The study did not measure vision recovery.
"Nothing like this has been attempted in humans before," says Evan Lewis, MD, a neurologist at the University of Toronto and the study's lead author. "Results from this trial are a very important step towards a clinical therapy for people with diabetic neuropathy."
According to Dr. Lewis, the next steps for the research team will be to conduct a phase 3, randomized controlled trial involving a larger group of participants.