Enhanced Oxidative Stress and Other Potential Biomarkers for Retinopathy in Type 2 Diabetics: Beneficial Effects of the Nutraceutic Supplements

Abstract

We have studied the global risk of retinopathy in a Mediterranean population of type 2 diabetes mellitus (T2DM) patients, according to clinical, biochemical, and lifestyle biomarkers. The effects of the oral supplementation containing antioxidants/omega 3 fatty acids (A/ω3) were also evaluated. Suitable participants were distributed into two main groups: (1) T2DMG (with retinopathy (+DR) or without retinopathy (-DR)) and (2) controls (CG). Participants were randomly assigned (+A/ω3) or not (-A/ω3) to the oral supplementation with a daily pill of Nutrof Omega (R) for 18 months. Data collected including demographics, anthropometrics, characteristics/lifestyle, ophthalmic examination (best corrected visual acuity, ocular fundus photographs, and retinal thickness as assessed by optical coherence tomography), and blood parameters (glucose, glycosylated hemoglobin, triglycerides, malondialdehyde, and total antioxidant capacity) were registered, integrated, and statistically processed by the SPSS 15.0 program. Finally, 208 participants (130 diabetics (68 +DR/62 -DR) and 78 controls) completed the follow-up. Blood analyses confirmed that the T2DMG+DR patients had significantly higher oxidative stress (p < 0.05), inflammatory (p < 0.05), and vascular (p < 0.001) risk markers than the T2DMG-DR and the CG. Furthermore, the A/ω3 oral supplementation positively changed the baseline parameters, presumptively by inducing metabolic activation and ameliorating the ocular health after 18 months of supplementation.

Figure 1

Flowchart of the challenges for the recruitment and screening methods of the study participants: characteristics of recruitment, sample size, and study design.

Figure 2

Percentages of development or progression of DR in the participants during the study course, according to being assigned or not to the oral supplementation. +A/ω3: oral supplementation with antioxidants and omega 3 fatty acids. –A/ω3: without taking the oral supplementation. T2DM+DR: type 2 diabetics with retinopathy. T2DM−DR: type 2 diabetics without retinopathy.

Figure 3

Oxidative and antioxidant status in the type 2 diabetics during the 18 months of follow-up, according to being assigned or not to the oral supplementation of A/ω3 supplements. T2DR+A/ω3: type 2 diabetics with retinopathy taking the oral supplementation; T2DR−A/ω3: type 2 diabetics with retinopathy not taking the oral supplementation; +A/ω3: assigned to the oral supplementation; −A/ω3: not assigned to the oral supplementation.