An Important New Role for Vitamin C in the Eye and the Brain and for Glaucoma

We know how important vitamin C is for so many functions in our bodies: supporting the immune system, protection against cardiovascular and heart disease and a protective and preventive role in cancer. However, a surprising new discovery may mean vitamin C is required by the nerve cells in the eye in order to function properly.

The function of vitamin C in the brain is not well understood; in fact, when the human body is deprived of vitamin C, the vitamin stays in the brain longer than anywhere else in the body. This new study by scientists at Oregon Health & Science University in the USA, who recently published their findings in the Journal of Neuroscience, may also throw light on the link between scurvy and depression. Scurvy results from a severe lack of vitamin C and one of the common symptoms is depression, and that may come from the lack of vitamin C in the brain.

As for its effects on eye health, Henrique von Gersdorff, Ph.D., a senior scientist at OHSU’s Vollum Institute (a privately endowed research unit of Oregon Health & Science University) said: “We found that cells in the retina need to be ‘bathed’ in relatively high doses of vitamin C, inside and out, to function properly. Because the retina is part of the central nervous system, this suggests there’s likely an important role for vitamin C throughout our brains, to a degree we had not realized before.”

The brain has special receptors, called GABA-type receptors that help modulate the rapid communication between cells in the brain. These act as an inhibitory “brake” on excitatory neurons in the brain and the OHSU researchers found that these GABA-type receptors in the retinal cells stopped functioning properly when vitamin C was removed. Because retinal cells are a kind of very accessible brain cell, it’s likely that GABA receptors elsewhere in the brain also require vitamin C to function properlyand because vitamin C is a major natural antioxidant, it may be that it essentially ‘preserves’ the receptors and cells from premature breakdown.

The findings could have implications for other diseases, like glaucoma and epilepsy as both conditions are caused by the dysfunction of nerve cells in the retina and brain that become over excited in part because GABA receptors may not be functioning properly. This indicates that a vitamin C-rich diet could be neuroprotective for the retina, particularly for people who are especially prone to glaucoma.

This research is in its early stages and speculative in nature, but it would be a sensible precaution to ensure adequeate vitamin C in your diet. Personally, I take a buffered vitamin C powder daily of at least 1gram and if ill or stressed I increase that to my personal body tolerance which is around 3grams a day. Eating oranges is just not enough to give you the protection you need from this vital nutrient.

Vitamin E in Contact Lenses Could Treat Glaucoma

Glaucoma is second only to cataracts as the leading cause of vision loss and blindness in the world as it affects almost 67 million people. Eye drops that relieve the abnormal build-up of pressure inside the eye that occurs in glaucoma, are a mainstay treatment but now there may be an alternative.

Research carried out at the University of Florida reports that if vitamin E is added into special medicated contact lenses it can keep the glaucoma medicine near the eye. This means it can more effectively treat the condition, up to nearly 100 times longer than possible with current commercial lenses.

Anuj Chauhan, Ph.D., who headed the research team, explained: “The problem is within about two to five minutes of putting drops in the eye, tears carry the drug away and it doesn’t reach the targeted tissue. Much of the medicine gets absorbed into the bloodstream, which carries it throughout the body where it could cause side effects. Only about one to five percent of drugs in eye drops actually reach the cornea of the eye.”

Chauhan and his colleagues have developed a new extended-release delivery approach by incorporating vitamin E into contact lenses. The vitamin E molecules form a kind of transport barrier that slows down the release of the glaucoma medication from the lens into the eye. The drug molecules can’t go through the vitamin E but must go around it and so get diverted and must find a longer path into the bloodstream. This increases the duration of the drug release from the lenses and so stays in the tears far longer than the 2-5 minutes with eye drops, leading to more effective therapy.

Don’t – please don’t – try adding vitamin E to your own contact lenses as this is very much in the development stage, but it is hoped clinical trials of the new lenses could begin within a year to 2 years.