Vitamin C is a water-soluble vitamin perhaps best known for its role in immune-system health: it protects you from infection, helps heal wounds and cuts and assists in red blood cell formation and repair. Vitamin C also acts as a factor in the production of collagen, an important connective tissue in the body, and helps the body absorb iron from plants we eat. Additionally, vitamin C, also known as ascorbic acid, can act as a protective antioxidant—meaning it protects body cells and tissues from the damage caused by free radicals.
Most fruits and vegetables are excellent sources of vitamin C. Fruits that are good sources include cantaloupe, grapefruit, oranges, papaya and strawberries. Rich vegetable sources include dark green leafy vegetables, sweet potatoes and red peppers. Some fruit drinks and juices are also fortified with vitamin C.
Severe vitamin C deficiency is rare in the United States and industrialized countries. Long-term, severe deficiencies could lead to scurvy. Symptoms of scurvy include inflamed and bleeding gums, impaired wound healing and excessive bleeding. At one time scurvy was common in sailors on long trips. When its cause was discovered, limes and other citrus foods were packed aboard on long journeys and effectively put an end to the problem. Bringing limes aboard is purported to be the reason sailors came to be called “limeys.”
Individuals who smoke require an additional 35 mg of vitamin C daily compared to nonsmokers. Scientists have not been able to identify the specific reason that smokers need more, just that blood levels in smokers are lower than in nonsmokers eating similar amounts of the vitamin and that smokers’ bodies tend to use up and metabolize more vitamin C. Nonsmokers regularly exposed to tobacco smoke are encouraged to ensure they meet the RDA for vitamin C.
Large doses of vitamin C, primarily from supplements, can cause gastrointestinal disturbances, such as diarrhea and bloating.
The following table lists the recommended intake for healthy people based on current scientific information.