Diabetic retinopathy is a leading cause of blindness. It occurs when diabetes damages tiny blood vessels inside the retina (the light-sensitive tissue at the back of the eye). There may be an association between the use of vitamin C and E supplements and a reduced risk of diabetic retinopathy.
A study published in the American Journal of Clinical Nutrition examined 1,353 type 2 diabetics who were diagnosed from 1993 to 1995. Data from these subjects revealed no association of diabetic retinopathy with vitamins C and E from food alone, but a decreased risk was found among those who reported long-term (> 3 years) use of vitamin C or E or multivitamin supplements. Compared to those who did not report supplement use, long-term supplement users experienced a two-fold reduction in the risk of developing diabetic retinopathy.
Although there had previously been evidence of this association from in vitro, animal, and short-term research, this was the first epidemiologic study on retinopathy to show the same protective effect associated with supplemental vitamin C and vitamin E.
American Journal of Clinical Nutrition, Vol. 79, No. 5, 865-873, May 2004
http://www.ajcn.org/cgi/content/abstract/79/5/865
