Omega-3 Fatty Acids Reduce the Risk of Diabetic Retinopathy
JAMA Ophthalmology, October 2016
Experimental studies indicate that consumption of long-chain omega-3 polyunsaturated fatty acids (LCω3PUFAs) protects against diabetic retinopathy (DR). Sala-Vila et al. examined this association in humans by conducting a long-term prospective study of 3,482 patients with type 2 diabetes (mean age, 67 years; 48% men) enrolled in the PREDIMED trial. They found that consumption of LCω3PUFAs (≥500 mg/d) significantly reduced the risk of DR.
Nutrient intake was determined with a validated food frequency questionnaire, administered annually. After collection of baseline data, patients were randomized to receive a Mediterranean diet supplemented with extra virgin olive oil (n = 1,236) or nuts (n = 1,095) or a control diet with recommendations to reduce fat intake (n = 1,151). The primary outcome measure was DR requiring intervention. Data were adjusted for potential confounders and validated with sensitivity analyses.
Participants were monitored for a median of 6 years, and 69 new DR events were recorded. At baseline, 75% of participants met the target for LCω3PUFA consumption (≥500 mg/d). The relative risk of incident sight-threatening DR for these participants was 46% lower than for those who consumed less LCω3PUFA (p = .001), regardless of the assigned diet. Risk reduction was even greater for patients with hypertension or advanced diabetes. Participants who consumed at least 2 servings of oily fish per week at baseline also had a lower risk of DR.
Because the PREDIMED trial was not designed to examine DR, and the participants generally had a plant-based Mediterranean diet, these findings need to be validated in other populations, the authors noted. Nevertheless, they recommend that middle-aged and older patients with type 2 diabetes consume at least 500 mg/d of dietary LCω3PUFA (e.g., from oily fish) to decrease their risk of sight-threatening DR.
The original article can be found here.