We’ve all heard about how great carrots and Beta-Carotene are for vision – but new evidence sites Vitamin C as being just as important!
Nerve cells in your eye require Vitamin C in order to function properly — a surprising discovery that may mean Vitamin C is required elsewhere in the brain for its proper functioning, according to a new study by scientists at Oregon Health & Science University recently published in the July 14, 2011, Journal of Neuroscience.“We found that cells in the retina need to be ‘bathed’ in relatively high doses of Vitamin C, inside and out, to function properly,” said Henrique von Gersdorff, Ph.D., a senior scientist at OHSU’s Vollum Institute and a co-author of the study. “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!”
Your brain has special receptors, called GABA-type receptors that help modulate the rapid communication between cells in your brain – sort-of like a traffic cop. GABA receptors in your brain act as an inhibitory “brake” on excitatory neurons in the brain. 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 because Vitamin C is a major natural antioxidant, it may be that it essentially ‘preserves’ the receptors and cells from premature breakdown, von Gersdorff said.
What Does this Mean for Your Eye Health?
Vitamin C, also known as ascorbic acid, is a water-soluble Vitamin which is essential for the normal functioning of every cell in your body. Benefits of Vitamin C may include protection against immune system deficiencies, cardiovascular disease, prenatal health problems, eye disease and even skin wrinkling.
Unlike most mammals, we humans don’t have the ability to make our own Vitamin C – We must obtain Vitamin C through our diet.Because it isn’t stored in the body either, you should eat foods high in Vitamin C every day.
Although citrus fruits are a great source of Vitamin C, other not so obvious foods contain Vitamin C as well:
- Eat more Broccoli. A 1/2-cup serving provides 45 mg of Vitamin C.
- Add a slice of Tomato to your sandwiches. A small Tomato provides 25 mg of Vitamin C.
- Slice up a Papaya or Mango for dessert. Half a medium Papaya or Mango provides 95 mg of Vitamin C.
- Think peppers! Red, Yellow and Orange Peppers have about twice the Vitamin C of Green Peppers.
- More obscure vegetables, like Kohlrabi and Jicama, provide about 45 mg of Vitamin C per half cup. Just grate each into a green salad.
- Believe it or not,Potatoes contain Vitamin C, too! A small baked Potato has 25 mg.
- Kiwi fruit, the fuzzy little brown fruit with the deep green interior, has about 55 mg of Vitamin C.
The dietary supplement and functional food market for eye health is being driven by several major forces: An aging population, unhealthy diets, an increased demand for natural ingredients and rising healthcare costs. “It is just not practical for most people to consume the required servings of fruits and vegetables needed on a consistent basis, whereas taking a once-daily supplement is safe, effective, and easy to do,” saysresearcher Mark Moyad, MD, MPH, of the University of Michigan. He further states: “The more we study Vitamin C, the better our understanding of how diverse it is in protecting our health, from cardiovascular, cancer, stroke, eye health [and] immunity – to living longer.”
Most of the science in this area has focused on the macula – a small yellow spot of about five millimeters diameter on the retina – and a corresponding condition called age-related macular degeneration (AMD). The yellow color is due to the content of the carotenoids lutein and zeaxanthin, which we derive from our diet and these two nutrients absolutely dominate the $138m US eye health ingredients market, according to Frost & Sullivan (2008 data)