Diet and risk of diabetic retinopathy: a systematic review

Diabetic retinopathy is a microvascular complication of diabetes that threatens all individuals with diabetes, leading to vision loss or blindness if left untreated. It is frequently associated with diabetic macular edema, which can occur at any point during the development of diabetic retinopathy. The key factors known to lead to its development include hyperglycemia, hypertension, and the duration of diabetes. Though the diet is important in the development of diabetes, its role in diabetic retinopathy has not been clearly identified. In this systematic review, we aimed to identify, summarize and interpret the literature on the association between the diet and dietary intakes of specific foods, nutrients, and food groups, and the risk of diabetic retinopathy. We searched PubMed and Web of Science for English-language studies evaluating the association between the dietary intake of individual foods, macro or micronutrients, dietary supplements, and dietary patterns and their association with retinopathy or macular edema. After reviewing potentially relevant abstracts and, when necessary, full texts, we identified 27 relevant studies. Identified studies investigated intakes of fruit, vegetables, fish, milk, carbohydrates, fibre, fat, protein, salt, potassium, vitamins C, D, and E, carotenoids, dietary supplements, green tea and alcohol. Studies suggest that adherence to the Mediterranean diet and high fruit, vegetable and fish intake may protect against the development of diabetic retinopathy, although the evidence is limited. Studies concerning other aspects of the diet are not in agreement. The role of the diet in the development of diabetic retinopathy is an area that warrants more attention.