Micronutrient Deficiencies and Nutritional Pattens as Possible Risk Factors in the Onset of Retinopathy in Type 2 Diabetic Patients

Diabetic retinopathy (DR) is a common complication in diabetes. Many studies have demonstrated a strong correlation between diet and the onset and progression of diabetes, but only few focused on possible link between nutritional patterns, micronutrient deficiency and DR. In this observational study, by using 10-day food diary recordings, we analyzed the eating habits of 34 patients affected by DR, 35 controls with a long history of type 2 diabetes mellitus (T2DM) but no retinopathy and 35 matched healthy subjects. Macro- and micronutrient intakes were calculated based on the Italian food composition database of the Center of Research for Food and Nutrition (CREA) by using a validated nutritional software. Moreover, the adherence to the Mediterranean diet (MD) was evaluated by using a widely adopted questionnaire. Respect to the type 2 diabetic group the average daily intake of vitamin A (total retinol activity equivalents) was strongly reduced in DR group (524 vs 1072 mg/d, P<0.01); those of vitamin C was also reduced in DR group (48.0 vs 85.2 mg/d, P<0.01) as well as vitamin D (3.73 vs 5.40 mg/d, P<0.01). Copper average daily intake was lower in DR group (0,50 vs 0,82 mg/d, P<0.01) and similarly potassium intake was lower in this group respect to the type 2 non retinopathic diabetic one (1271 vs 2180 mg/d, P<0.01). DR patients also showed a significatively lower adherence to the MD respect to the T2DM patients and to the healthy subjects. This study confirmed a possible role of unhealthy nutritional patterns and micronutrient deficiency in the development and progression of the diabetic retinopathy.