Vitamin C is well-known as an important component of your immune system; it's also a component of collagen, which is needed for healthy connective tissue. It also helps your bones and teeth stay strong.
Vitamin C is an antioxidant that protects the cells in your body from free radical damage.
Daily Requirements
Males
1 to 3 years: 15 milligrams per day
4 to 8 years: 25 milligrams per day
9 to 13 years: 45 milligrams per day
14 to 18 years: 75 milligrams per day
19+ years: 90 milligrams per day
Females
1 to 3 years: 15 milligrams per day
4 to 8 years: 25 milligrams per day
9 to 13 years: 45 milligrams per day
14 to 18 years: 65 milligrams per day
19+ years: 75 milligrams per day
Vitamin C supplements have been recommended for relief of colds and flu, and as an alternative treatment for some forms of cancer. However, research hasn't provided sufficient evidence for these recommendations.
Taking large amounts of supplemental vitamin C may result in diarrhea or loose stools. The Institute of Medicine established 1,800 to 2,000 milligrams per day as the upper tolerable intake level.
Vitamin C is found naturally in fruits and vegetables, especially citrus fruits, strawberries, peppers, tomatoes, broccoli and potatoes. Deficiency can lead to dry hair, gingivitis, slow wound healing, a weakened immune system, anemia and nosebleeds. Scurvy is a disease that will occur after a long-standing deficiency.
Sources:
"Vitamin C." Accessed March 17, 2009. http://www.nlm.nih.gov/medlineplus/ency/article/0024204.htm
Otten JJ, Hellwig JP, Meyers LD. "Dietary Reference Intakes: The Essential Guide to Nutrient Requirements." IOM, 2006.


