Vitamin C is a trace nutrient required by the body to build connective tissues, heal wounds, fuel the immune system and stop bleeding. It is commonly found in citrus fruits and rare fresh organ meat. Although the vitamin can be produced by most plants and animals, some animals, including humans and the closely related primates cannot produce Vitamin C on their own and must obtain it from dietary sources.
Lack of Vitamin C leads to scurvy, which is characterized by extreme fatigue and bleeding of the gums. Scurvy was endemic among sailors and polar explorers until the mid 19th century, when it was noted that lemon juice would keep away the symptoms indefinitely.
60mg of Vitamin C, approximately the amount in one glass of orange juice, is sufficient to ward off scurvy, although the recommended daily minimum is 90mg per day. As such, it is today a very rare disease and generally only occurs in persons who have deliberately eliminated citrus fruits from their diet. This is not uncommon among patients with a gastric ulcer.
Benefits of higher doses of vitamin C are currently regarded with some suspicion. However, an increase of vitamin C input during periods of illness is often therapeutic.