vitamin C
Alternative Namesascorbic acid
Definition
Vitamin C is a water-soluble vitamin. Water-soluble vitamins are carried throughout the body in the bloodstream. They are, for the most part, not stored in the body. The body uses what it needs and the rest is passed in the urine.
What food source is the nutrient found in?
The best sources of vitamin C are fruits and vegetables. Citrus fruits such as oranges, grapefruit, and tangerines are excellent sources. Other good sources of vitamin C include:
- broccoli, cabbage, and brussels sprouts
- melons, kiwifruit, and strawberries
- sweet peppers, potatoes with skin, and tomatoes
Guidelines for eating fruits and vegetables with a high vitamin C content include:
- Choose fresh or frozen fruits and vegetables over canned products.
- Cook vegetables only for a short time in a small amount of water.
- Eat raw vegetables when feasible.
- Eat sliced fruits and vegetables shortly after they have been cut.
- Keep fruits and vegetables refrigerated, and eat them while they are fresh.
How does the nutrient affect the body?
Vitamin C is important to many body functions. It helps the body do the following:
- build and maintain collagen, which are fibers that connect tendons, ligaments, bones, and cartilage
- heal wounds and bruises
- keep the immune system healthy
- maintain healthy bones, teeth, gums, red blood cells, and blood vessels
- repair bone fractures
Vitamin C may reduce the risk of certain chronic diseases by acting as an antioxidant. Antioxidants help the body fight the effects of free radicals. These are toxic by-products made when the cells use oxygen, that can damage the body's cells.
Information
Scurvy is a disease caused by a deficiency of vitamin C. It causes open sores in the mouth, loose teeth, and soft gums. In the 1700s, it was discovered that sailors who often drank lime juice did not get scurvy. Sailors who did not drink lime juice had a 50% chance of dying from scurvy. It was not until 200 years later that vitamin C was found to prevent scurvy.
Severe deficiency of vitamin C can lead to scurvy. However, severe deficiency and scurvy are rare in developed nations. Vitamin C deficiency is often caused by the following factors:
Factors that increase an individual's need for vitamin C include:
- inflammatory diseases
- gastrointestinal diseases
- hyperthyroidism
- burns
- surgery
- pregnancy
- breastfeeding
Signs of vitamin C deficiency include:
- inflamed gums
- reduced resistance to colds and infections
- skin problems
- slow wound healing
- stomach disorders
Consuming more than 2,000 mg per day of vitamin C can cause stomach upset and diarrhea and possibly other adverse effects. It has been suggested that large doses (10 to 100 or more times the routinely recommended doses) of vitamin C can help decrease the risk for cancer and heart disease. Although studies have produced conflicting results, the weight of the evidence now suggests that this claim is unfounded.
It is unclear from studies whether physical activity increases a person's requirement for vitamin C. There is no substantial evidence that mental or emotional stress increases the need for vitamin C for healthy people.
Many studies have been done to determine the effect vitamin C has on the common cold. Review of these studies shows that larger doses of vitamin C, 500 mg per day to 1,000 mg per day, for example, have no significant effect on preventing colds. These doses may, however, reduce the duration and severity of a cold for some people. This may be because at high doses, vitamin C may act like an antihistamine.
The recommended dietary allowances, or RDAs, for vitamin C are 75 mg per day for women and 90 mg per day for men. Smokers are advised to consume an extra 35 mg daily. This is because smoking depletes the body of some vitamin C. The RDA for pregnant women is 85 mg per day. Women who breastfeed should consume 120 mg per day.
The Third National Health and Nutrition Survey, also called NHANES III, showed that 11% of nonsmoking women and 21% of nonsmoking men in the United States do not get enough vitamin C. Because vitamin C cannot be stored in the body, it is important to eat foods rich in vitamin C daily. Eating a well-balanced diet, including at least five servings of fruit and vegetables every day, should provide all the body needs.
Author:Susan Harrow Rago, RD, MS
Date Written:06/07/01
Medical Review:Steve Houseworth, MD
Date Written:9/7/2006
Reviewer:Reginald Finger, MD
Date Reviewed:1/23/2007
Contributors
Potential conflict of interest information for reviewers available on request
