(See also Overview of Vitamins.)
Vitamin C (ascorbic acid) is essential for the formation, growth, and repair of bone, skin, and connective tissue (which binds other tissues and organs together and includes tendons, ligaments, and blood vessels). Vitamin C helps maintain healthy teeth and gums. It helps the body absorb iron, which is needed to make red blood cells. Vitamin C also helps burns and wounds heal.
Good sources of vitamin C include citrus fruits, tomatoes, potatoes, broccoli, strawberries, and sweet peppers.
Like vitamin E, vitamin C is an antioxidant: It protects cells against damage by free radicals, which are by-products of normal cell activity and which participate in chemical reactions within cells. Some of these reactions can cause damage over a person's lifetime.
Not eating enough fresh fruits and vegetables can cause the deficiency.
People feel tired, weak, and irritable.
Severe deficiency, called scurvy, causes bruising, gum and dental problems, dry hair and skin, and anemia.
The diagnosis is based on symptoms and sometimes blood tests.
Increasing consumption of fresh fruits and vegetables or taking vitamin C supplements by mouth usually corrects the deficiency.
In adults, vitamin C deficiency usually results from
For example, vitamin C deficiency may result from a diet deficient in fresh fruits and vegetables. Also, cooking can destroy some of the vitamin C in food.
The following conditions can significantly increase the body’s requirements for vitamin C and the risk of vitamin C deficiency:
Adults feel tired, weak, and irritable if their diet is low in vitamin C. They may lose weight and have vague muscle and joint aches.
The symptoms of scurvy develop after a few months of deficiency. Bleeding may occur under the skin (particularly around hair follicles or as bruises), around the gums, and into the joints. The gums become swollen, purple, and spongy. The teeth eventually loosen. The hair becomes dry and brittle, and the skin becomes dry, rough, and scaly. Fluid may accumulate in the legs. Anemia may develop. Infections may develop, and wounds do not heal.
Infants may be irritable, have pain when they move, and lose their appetite. Infants do not gain weight as they normally do. In infants and children, bone growth is impaired, and bleeding and anemia may occur.
The diagnosis of scurvy is based on symptoms. Measuring the vitamin C level in blood can help establish the diagnosis, but this test is not always available.
Blood tests may be done to check for anemia.
In children, x-rays are done to check for impaired bone growth.
Scurvy is treated with high doses of daily vitamin C supplements, followed by a nutritious diet that supplies 1 to 2 times the daily recommended amount of vitamin C. The diet should include increased consumption of fresh fruits and vegetables.
Most symptoms disappear after 1 to 2 weeks.
Vitamin C plus iron supplements can cure the anemia.
Some people take high doses of vitamin C because it is an antioxidant, which protects cells against damage by free radicals. Free radicals are thought to contribute to many disorders, such as atherosclerosis, cancer, lung disorders, the common cold, eye cataracts, and memory loss. Whether taking high doses of vitamin C protects against or has any beneficial effect on these disorders is unclear. Evidence of a protective effect against cataracts is strongest.
High doses (up to the safe upper limit—2,000 milligrams a day) of vitamin C are usually not toxic to healthy adults. Occasionally, higher doses cause nausea or diarrhea and interfere with the interpretation of some blood test results.