Oral Antioxidant Supplementation for Diabetic Retinopathy

A study examining antioxidant supplementation as a treatment for diabetic retinopathy was published in the September/October 2011 issue of European Journal of Ophthamology.  It was a report on a clinical trial—the first of its kind (to the authors’ knowledge)—and the article is “A 5-year follow-up of antioxidant supplementation in type 2 diabetic retinopathy.”

The study focused on type 2 diabetes patients who had nonproliferative diabetic retinopathy (DR). There were 105 patients in the study.

Each patient had a complete ophthalmic examination.  Additionally, researchers obtained a plasma determination of oxidative (malonyldialdehyde [MDA]) and antioxidant parameters (total antioxidant status [TAS]) at baseline.

Then one part of the patient population was randomly assigned to take oral antioxidant supplementation (at nutritional doses).

There were 97 patients who completed the 5-year follow-up period, and the same examinations (complete ophthalmic, MDA, and TAS) were done on those patients.

The following were compared for the beginning of the study and the end of follow-up:

• best-corrected visual acuity
• DR score
• MDA value
• TAS value

The study found that supplementation with an oral antioxidant did not change best-corrected visual acuity.  The retinopathy stage, though, did who a slowing of progression for those taking the supplement; for those were not taking the antioxidant supplement, retinopathy stage worsened.

Additionally, those taking the supplement maintained antioxidant plasma status levels.

The study concludes that oral antioxidant supplementation may be a useful adjunct long-term therapy for patients with type 2 diabetes who have nonproliferative diabetic retinopathy.