Long-Term Vision for Vitamin C and Diabetic Eye Health

We’ve all taken vitamin C tablets, chewables, or “super” juice drinks before. Our parents told us it helps prevent colds and flu, teachers say vitamin C helps keep our teeth from falling out, and you might have a few friends or relatives who swear by taking in megadoses of vitamin C to cure a fever overnight. Their claims all have substance to it, but did you know vitamin C can also help prevent blindness induced by diabetes? That’s right, there is a possibility that vitamin C might just help with diabetic retinopathy and a study cites the possibility.

Preventing Diabetic Retinopathy with Vitamin C Supplementation

The study investigated the effects of vitamin C supplementation on diabetic rats. The rats were divided into three groups: control rats (CON), STZ-induced diabetic rats (STZ), and STZ rats supplemented with vitamin C (STZ-vitC). For supplementation of vitamin C, ascorbic acid (1 g/l) was added into the drinking water. The results of the study after 36 weeks showed remarkable results.

In conclusion, vitamin supplementation suppressed leukocyte adhesion and thus endothelial dysfunction, associated with increase in iris blood flow perfusion in diabetes. The antioxidant vitamin C may be a therapeutic agent for preventing diabetic retinopathy.

While this does sound like a promising venture, specially because vitamin C is not only accessible but also dirt cheap, let’s not forget the study was conducted on rats and not people. If this study is correct and we try to apply this to diabetic human beings, we would need large amounts of vitamin C if only because humans don’t produce vitamin C the way rats can. And they produce so much compared to their body weight too, which means they don’t really need vitamin C supplementation to survive, and the vitamin C induced was more of a surplus, a big one at that.

We did try to unearth some recent data that tries to replicate the study in human beings and unfortunately, the ones we found were unable to show a significant correlation. Still, the promise of long term eye health and vitamin C supplementation is definitely there, but it’s a tough call with regards to preventing diabetic retinopahy.
Jariyapongskul A, Rungjaroen T, Kasetsuwan N, Patumraj S, Seki J, Niimi H. Long-term effects of oral vitamin C supplementation on the endothelial dysfunction in the iris microvessels of diabetic rats. Microvasc Res. 2007;74(1):32-8.,

Credit: Puhhha