In a surprising discovery, researchers found that nerve cells in the retina need to be 'bathed' in relatively high doses of vitamin C to maintain proper function. This may mean that vitamin C is required elsewhere in the brain for its proper functioning, say the scientists from Oregon Health & Science University. The vitamin C research work was done using goldfish retinas, which have the same overall biological structure as human retinas.
"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." said Henrique von Gersdorff, Ph.D., a senior scientist at OHSU's Vollum Institute and a co-author of the study.
The brain, like the retinas, have special receptors, called GABA-type receptors that help modulate communication between brain cells by inhibiting the action of excitatory neurons. 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 properly, von Gersdorff said. And, as a major natural antioxidant, vitamin C may help 'preserve' the receptors and cells from premature breakdown, von Gersdorff said.
The findings could have implications for the dysfunction of nerve cells in the retina and brain that become over excited in part because GABA receptors may not be functioning properly. The researchers hope that the important insights gained will lead to the generation of new hypotheses and potential nutrition strategies. "For example, maybe a vitamin C-rich diet could be neuroprotective for the retina…von Gersdorff said. This is speculative and there is much to learn.
While the function of vitamin C in the brain is not well understood, we do know that when the human body is deprived of vitamin C, the vitamin stays in the brain longer than anyplace else in the body. "Perhaps the brain is the last place you want to lose vitamin C," von Gersdorff said.
Oregon Health & Science University