title: Vitamin C and Infections.
abstract: In the early literature, vitamin C deficiency was associated with pneumonia. After its identification, a number of studies investigated the effects of vitamin C on diverse infections. A total of 148 animal studies indicated that vitamin C may alleviate or prevent infections caused by bacteria, viruses, and protozoa. The most extensively studied human infection is the common cold. Vitamin C administration does not decrease the average incidence of colds in the general population, yet it halved the number of colds in physically active people. Regularly administered vitamin C has shortened the duration of colds, indicating a biological effect. However, the role of vitamin C in common cold treatment is unclear. Two controlled trials found a statistically significant dose-response, for the duration of common cold symptoms, with up to 6-8 g/day of vitamin C. Thus, the negative findings of some therapeutic common cold studies might be explained by the low doses of 3-4 g/day of vitamin C. Three controlled trials found that vitamin C prevented pneumonia. Two controlled trials found a treatment benefit of vitamin C for pneumonia patients. One controlled trial reported treatment benefits for tetanus patients. The effects of vitamin C against infections should be investigated further.
authors.affiliation: Department of Public Health, University of Helsinki, Helsinki FI-00014, Finland. harri.hemila@helsinki.fi.
authors.forename: Harri
authors.initials: H
authors.lastname: Hemilä
mesh_terms: D000818:Animals; D001205:Ascorbic Acid / Q000627:therapeutic use*; D001206:Ascorbic Acid Deficiency / Q000150:complications; D003139:Common Cold / Q000188:drug therapy*; D006801:Humans; D011014:Pneumonia / Q000188:drug therapy* / Q000209:etiology / Q000517:prevention & control; D013742:Tetanus / Q000188:drug therapy; D014815:Vitamins / Q000627:therapeutic use*
chemical_list: D014815:Vitamins; D001205:Ascorbic Acid
keywords: ascorbic acid; bacteria; bacterial toxins; common cold; herpes zoster; pneumonia; protozoa; respiratory tract infections; tetanus; viruses