Your daily glass of orange juice in the morning may protect the health of your eyes, several recent studies suggest. In particular, it may guard against common eye diseases, including age related macular degeneration, cataracts and glaucoma. Also known as ascorbic acid, vitamin C provides structure and support to the eye and also protects the cells in your eye from damage. In fact, your eyes contain one of the highest levels of vitamin C in the entire body, with greater than 60 times the content in the bloodstream.
Age Related Macular Degeneration
Those at high risk for age related macular degeneration, ARMD, may benefit from consuming vitamin C along with several other antioxidants and minerals, researchers purport in a 2001 study in the "Archives of Ophthalmology." ARMD is a condition in which the macula, or the central portion of your eye that provides visual acuity and central vision, slowly deteriorates with age. ARMD is the most common cause of visual deterioration in individuals older than 65 in the United States. The Age Related Eye Disease Study, one of the largest studies on ARMD, found that the risk of ARMD was decreased by 25 percent when vitamin C was used in conjunction with beta-carotene, vitamin E, copper and zinc. The risk of associated loss of vision was diminished by 27 percent.
Cataracts
High vitamin C intakes may protect against cataracts, according to a 2008 study published in the "American Journal of Clinical Nutrition." Cataracts are an eye condition characterized by a clouding or opacity of the lens of your eye. Participants who consumed higher amounts of vitamin C had a lower risk of cataracts than those who consumed a combination of vitamin C, vitamin E, zinc and beta carotene. The researchers attribute this finding to the antioxidant qualities of vitamin C, which minimizes damage from ultraviolet radiation and the build-up of oxidative radicals.
Glaucoma
Low levels of vitamin C in the blood may be associated with glaucoma, Japanese researchers suggest in the February 2010 issue of "Graefe's Archive of Clinical and Experimental Ophthalmology." The scientists found that vitamin C levels in participants with normal tension glaucoma were only 4.6 micrograms per milliliter, compared to 6.3 micrograms per milliliter in healthy participants. Similar results were not found with other antioxidants, such as vitamin A, B and E. The researchers propose that vitamin C may be a useful alternative treatment to those suffering from glaucoma.
Recommended Daily Intake
The recommended dietary allowance, RDA, of vitamin C for adults is 90 milligrams a day for males and 74 milligrams a day for females. The RDA for pregnant females is 85 milligrams a day and for lactating females is 120 milligrams a day. The tolerable upper intake level at which toxicity develops is 2,000 milligrams a day.
Sources of Vitamin C
Vitamin C can be found in a variety of fruits and vegetables. Sweet red peppers and orange juice contain one of the highest sources of vitamin C with 95 and 93 milligrams per serving respectively. Other good sources include grapefruit juice, green peppers, broccoli and strawberries. Vitamin C is also available as an over-the-counter supplement in the form of ascorbic acid or mineral salt varieties such as calcium ascorbate or sodium ascorbate.
References
- Office of Dietary Supplements: Vitamin C
- "Benefits of Nutritional Supplements"; Benefits of Antioxidants: May Help Protect Eyes, Lungs and Brain; Annette Dickinson; June 2002
- "Archives of Ophthalmology"; A Randomized, Placebo-Controlled, Clinical Trial of High-Dose Supplementation with Vitamins C and E, Beta Carotene, and Zinc for Age Related Macular Degeneration and Vision Loss: AREDS Report No.8; Age-Related Eye Disease Study Research Group; October 2001
- "American Journal of Clinical Nutrition"; Antioxidant Nutrient Intake and the Long-Term Incidence of Age-Related Cataract: The Blue Mountains Eye Study; Ava Grace Tan, et al.; June 2008
- "Graefe's Archive of Clinical and Experimental Ophthalmology"; Reduced-Serum Vitamin C and Increased Uric Acid Levels in Normal-Tension Glaucoma; K. Yuki, et al.; February 2010
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