Two Natural Substances Important for the Eyes

A recently published study investigated the effects of docosahexanoic acid (DHA)and lutein on diabetic retinopathy, a condition in which there is damage to the retina in the eye. Diabetics are at high risk for developing retinopathy due to microvascular damage commonly seen after prolonged periods of elevated bloodsugar. In fact, most diabetics, particularly those with poorly controlled blood sugar levels, will develop some type of retinopathy.

In this new study, researchers investigated the potential protective effects of the omega-3 fatty acid, DHA, and the carotenoid lutein on experimentally induced diabetic retinopathy. Three groups of mice were treated with DHA and lutein for 12 weeks. One group was comprised of mice without diabetes, a second group included mice with diabetes and no insulin treatment and the third group were mice with diabetes that received insulin.

The study showed that the diabetic mice had increased measurements of oxidative stress and apoptosis (programmed cell death) in the retina. Also, the diabetic mice had increased levels of nitrotyrosine in the retina, which is a marker of oxidative stress induced by reactive nitrogen species, such as peroxynitrite. The ganglion cell layer in the retinas of the diabetic mice was also significantly reduced in thickness indicating a loss of cells in this area. In addition, the diabetic mice exhibited abnormal readings on the electroretinogram, which measures electrical responses of various cell types in the retina.

Treatment with DHA and lutein alone or in combination with insulin reversed these pathological findings. Furthermore, DHA and lutein were able to inhibit these changes even under conditions of increased blood sugar (hyperglycemia).

The researchers concluded, “Lutein and DHA are capable of normalizing all the diabetes-induced biochemical, histological, and functional modifications. Specifically, the cell death mechanisms involved deserve further studies to allow the proposal as potential adjuvant therapies to help prevent vision loss in diabetic patients.”

Reference:

Arnal E, Miranda M, Johnsen-Soriano S, Alvarez-Nölting R, Díaz-Llopis M, Araiz J,Cervera E, Bosch-Morell F, Romero FJ. Beneficial effect of docosahexanoic acid and lutein on retinal structural, metabolic, and functional abnormalities in diabetic rats. Curr Eye Res. 2009 Nov;34(11):928-38.