The invention relates to a food supplement including a polyphenolic brown algae extract and at least one oil rich in omega-3 polyunsaturated fatty acids. Said supplement can be used as an antioxidant on the retina cells, as an activator of sirtuin 1 or as a reducer of retinal cell stress induced by high glucose levels. The supplement can also be used for treating and/or preventing chronic hyperglycaemia on the retina. The polyphenol reduces plasma glucose and increases mitochondrial activity. Omega-3 polyunsaturated fatty acids have beneficial effects on insulin resistance, type-2 diabetes. EPA (eicosapentaenoic acid) and DHA (docosahexanoic acid) are two polyunsaturated fatty acids of the omega-3 series, which are beneficial for health when added to a food composition in optimal quantities.
