Medical Encyclopedia: Vitamin C

Alternative names Ascorbic acid

Definition
Vitamin C is a water-soluble vitamin that is necessary for normal growth and development.

Function
Vitamin C is required for the growth and repair of tissues in all parts of your body. It is necessary to form collagen, an important protein used to make skin, scar tissue, tendons, ligaments, and blood vessels. Vitamin C is essential for the healing of wounds, and for the repair and maintenance of cartilage, bones, and teeth.
Vitamin C is one of many antioxidants. Vitamin E and beta-carotene are two other well-known antioxidants. Antioxidants are nutrients that block some of the damage caused by free radicals, which are by-products that result when our bodies transform food into energy.
The build up of these by-products over time is largely responsible for the aging process and can contribute to the development of various health conditions such as cancer, heart disease, and a host of inflammatory conditions like arthritis. Antioxidants also help reduce the damage to the body caused by toxic chemicals and pollutants such as cigarette smoke.
Vitamin C deficiency can lead to dry and splitting hair; gingivitis (inflammation of the gums) and bleeding gums; rough, dry, scaly skin; decreased wound-healing rate, easy bruising; nosebleeds; weakened enamel of the teeth; swollen and painful joints; anemia; decreased ability to ward off infection; and, possibly, weight gain because of slowed metabolic rate and energy expenditure. A severe form of vitamin C deficiency is known as scurvy, which mainly affects older, malnourished adults.
The body does not manufacture vitamin C on its own, nor does it store it. It is therefore important to include plenty of vitamin C-containing foods in your daily diet.

Food Sources
All fruits and vegetables contain some amount of vitamin C. Foods that tend to be the highest sources of vitamin C include green peppers, citrus fruits and juices, strawberries, tomatoes, broccoli, turnip greens and other leafy greens, sweet and white potatoes, and cantaloupe.
Other excellent sources include papaya, mango, watermelon, brussels sprouts, cauliflower, cabbage, winter squash, red peppers, raspberries, blueberries, cranberries, and pineapples.

Side Effects
Vitamin C is water soluble and is regularly excreted by the body. Therefore, toxicity is very rare. Amounts greater than 2,000 mg/day, however, are not recommended because such high doses can lead to stomach upset and diarrhea.

Recommendations
The best way to get the daily requirement of essential vitamins, including vitamin C, is to eat a balanced diet that contains a variety of foods from the food guide pyramid.
Vitamin C should be consumed every day because it is not fat-soluble and, therefore, cannot be stored for later use.
The recommened daily intakes of dietary vitamin C (according to the U.S. RDA) are listed below.

Pediatric
Neonates 1 to 6 months: 30 mg
Infants 6 to 12 months: 35 mg
Children 1 to 3 years: 40 mg
Children 4 to 6 years: 45 mg
Children 7 to 10 years: 45 mg
Children 11 to 14 years: 50 mg
Adolescent girls 15 to18 years: 65 mg
Adolescent boys 15 to18 years: 75 mg

Adult
Men over 18 years: 90 mg
Women over 18 years: 75 mg
Breastfeeding women: first 6 months: 95 mg
Breastfeeding women: second 6 months: 90 mg

Because smoking depletes vitamin C, people who smoke generally need an additional 35 mg/day.