Blood omega-3 biomarkers, diabetic retinopathy and retinal vessel status in patients with type 1 diabetes.

Background/objectives: Clinical research on dietary omega-3 fatty acids and retinal health in type 1 diabetes (T1D) is scarce. In patients with T1D, we examined the associations between blood biomarkers of marine omega-3 (which reflect their dietary intake) and prevalent diabetic retinopathy (DR), and retinal microvascular data obtained through optical coherence tomography angiography (OCTA).

Subjects/methods: Exploratory, cross-sectional sub-study of a prospective, consecutive, large-scale OCTA study conducted in a longitudinal cohort (ClinicalTrials.gov NCT03422965). We used baseline data from 188 consecutive patients with T1D and 88 controls. We determined blood omega-3 biomarkers (eicosapentaenoic [EPA], docosapentaenoic [DPA] and docosahexaenoic [DHA] acids) by gas-chromatography. Ocular data included DR grading, and 6 × 6 mm OCTA scans to obtain macular vessel density and perfusion density, and foveal avascular zone area, perimeter, and circularity.

Results: Patients with T1D, regardless of DR stage, showed significantly lower blood levels of EPA, DHA, DHA, and EPA + DHA than non-diabetic controls (P < 0.001, all cases). In multivariate models in patients with T1D, higher EPA was associated with a lower prevalence of DR (P = 0.044); and increasing proportions of DPA, DHA, EPA + DHA, and total marine omega-3 fatty acids related to a higher vessel and perfusion densities in the macula (P values from 0.014 to 0.050).

Conclusions: In patients with T1D, higher blood omega-3 status related to lower DR grades and preserved retinal perfusion. Our results, which are consistent with the current model of the pathogenesis of DR and data from experimental models, add to the notion of marine-derived omega-3 fatty acids as a healthy fat.