The effects of carrot carotenoids on diabetic retinopathy in Type 1 diabetes mellitus

Abstract

While carotenoids are essential for visual function, their potential role in diabetic retinopathy is not known. By providing carrot powder, this study examined carotenoid metabolism and visual function in Type 1 diabetes. Wistar rats (n=30) were assigned to diet either with or without carrot enrichment (15%, w/w) for 12 weeks. Type 1 diabetes was induced with streptozotocin at 3 weeks. Retinal function and anatomical integrity were assessed along with retinoid and carotenoid levels in the serum, liver, and retina. Loss of ERG oscillatory potentials, with normal histology indicated early stage retinopathy. Healthy animals fed carrot diet showed highest b-wave amplitudes; reflecting higher phototransduction. Diabetic animals fed carrot diet had the lowest b-wave amplitudes, reduced retinoids liver reserves, and highest α- and β-carotene, suggesting disturbance of conversion during diabetes. Consequently carrot powder at concentrations used by this study cannot be recommended for diabetic retinopathy.