Supplementation with a Highly Concentrated Docosahexaenoic Acid (DHA) in Non-Proliferative Diabetic Retinopathy: A 2-Year Randomized Double-Blind Placebo-Controlled Study

Abstract

We assessed the effect of a 2-year supplementation with a highly concentrated docosahexaenoic acid (DHA) product with antioxidant activity on non-proliferative diabetic retinopathy (NPDR) in a randomized double-blind placebo-controlled study. A total of 170 patients with diabetes were randomly assigned to the DHA group (n = 83) or the placebo group (n = 87). NPDR was diagnosed using non-contact slit lamp biomicroscopy examination, and classified into mild, moderate, and severe stages. Patients in the DHA group received a high rich DHA triglyceride (1050 mg/day) nutritional supplement, and those in the placebo group received olive oil capsules. The percentages of mild NPDR increased from 61.7% at baseline to 75.7% at the end of the study in the DHA group, and from 61.9% to 73.1% in the placebo group. Moderate NPDR stages decreased from 35.1% at baseline to 18.7% at the end of the study in the DHA group, and from 36.8% to 26.0% in the placebo group. In the DHA group, there were five eyes with severe NPDR at baseline, which increased to one more at the end of the study. In the placebo group, of two eyes with severe NPDR at baseline, one eye remained at the end of the study. Changes in visual acuity were not found. There were improvements in the serum levels of HbA1c in both groups, but significant differences between the DHA and the placebo groups were not found. In this study, the use of a DHA triglyceride nutraceutical supplement for 2 years did not appear to influence the slowing of the progression of NPDR.

Improvement of retinal function in Alzheimer disease-associated retinopathy by dietary lysophosphatidylcholine-EPA/DHA

“…Even with these high doses, the enrichment of retinal DHA was minimal. This could account for the failure of the large clinical trials to detect meaningful benefits of the currently available DHA supplements at safe doses 17 – 19 . In comparison, the dosage of LPC-EPA/DHA used in this study is equivalent to only 280 mg of omega 3 fatty acids per day for a 70 kg human subject, but resulted in a 50% increase in retinal DHA and 100-fold increase in retinal EPA in 2 months.…”

“…The deficiency of DHA is associated with various ocular diseases, including retinitis pigmentosa 12 , diabetic retinopathy 13 – 15 , age-related macular degeneration 16 , dry eye disease, and glaucoma 13 . Although both epidemiologic 13 , 16 and pre-clinical studies suggested beneficial effects of dietary DHA for retinal health, controlled clinical trials with the currently available supplements showed no significant benefit for retinopathy 17 – 19 , age-related macular degeneration 20 , 21 or glaucoma 22 , although a combination of DHA and citicholine, a precursor of phospholipids, was reported to improve symptoms in a small group of glaucoma patients 22 .…”

Nutraceuticals for Diabetic Retinopathy: Recent Advances and Novel Delivery Systems

“…In a randomized controlled trial (RCT) in patients with DME, intravitreal ranibizumab combined with DHA supplementation was shown to reduce central subfield macular thickness but did not improve the visual acuity as compared with ranibizumab alone after a 2-year follow-up [ 67 ]. Despite these findings, a prospective clinical study (PAOXRED study) showed that intake of 1050 mg/day DHA for 2 years did not appear to mitigate NPDR progression [ 68 ]. Likewise, a prospective clinical study (ASCEND-Eye) found that daily oral supplementation of 1 g omega-3 fatty acids [containing 460 mg Eicosapentaenoic acid (EPA) and 380 mg DHA] for 6.5 years did not yield better outcomes versus control in DR progression [ 69 ].…”