In a nutshell
This study looked at the impact of carotenoids to protect against the development of diabetic retinopathy (DR; eye disease). It found that daily carotenoid supplementation may improve the health of the retina and improve subtle changes in vision caused by DR.
Some background
DR is one of the most serious complications of diabetes. It can lead to blindness. Carotenoids are nutrients derived from vitamin A. Vitamin A is known to be very important for eye health.
Carotenoid levels in the retina (the thin tissue in the back of the eye involved in vision) such as lutein and zeaxanthin can be estimated by measuring the macular pigment optical density (MPOD). MPOD is a good marker of the health of the retina. Carotenoid supplements improve retinal health in patients with some eye conditions. However, it is not clear if carotenoid levels are reduced in diabetic patients, and if supplementing them can improve their outcome.
Methods & findings
This study reviewed all the studies involving the use of carotenoids in the treatment of DR. 18 studies were included. 7 of these studies involved animals. 11 studies involved humans.
7 of the human studies measured the MPOD in diabetic patients. They all found that the MPOD was significantly reduced in diabetic patients compared to patients without diabetes.
1 study treated 67 diabetic patients with either carotenoids or placebo for 6 months. 39 patients received 4 mg of lutein and 8 mg of zeaxanthin daily. 28 patients received a placebo daily. After 6 months, carotenoid supplementation resulted in a significant increase in MPOD. This also led to an improvement in contrast sensitivity and color vision which can be affected in early DR.
The bottom line
This study showed that MPOD levels are reduced in diabetic patients and that carotenoid supplements increase MPOD levels in these patients.
The fine print
Most of the data involves small studies. Larger studies are needed to confirm these findings.
Published By :
Nutrients
Date :
Jul 20, 2021
