Vitamin C and the Common Cold
Vitamin C (ascorbic acid) is one of the so-called water-soluble vitamins. It is necessary for many bodily processes, including iron absorption and collagen formation. Vitamin C is also an antioxidant that protects body cells and tissues from damage. Fruits (especially citrus fruits) and vegetables are excellent sources of vitamin C. This vitamin has been used to prevent and treat the common cold; however, evidence supporting its effectiveness remains controversial. A recent study lends more evidence to this issue. Japanese researchers randomized 244 people to receive ascorbic acid 50mg or 500mg daily for five years. At the end of the study, the group taking 500mg daily had significantly fewer colds than the group taking 50mg daily. There was no effect on the duration or severity of colds during the study period. The typical dose of vitamin C used to prevent the common cold is 200mg daily or more. Doses up to 2000 mg daily have been used to treat the common cold. Reported side effects of vitamin C are nausea, headache, vomiting, heartburn, and abdominal cramps.