Vitamin C
Place in Therapy
Place in Therapy
Duration of Cold Symptoms
A small amount of evidence exists for the supplementation of vitamin C to reduce the duration of cold symptoms (1). The evidence is not strong, the impact is not big, and the results were unable to be replicated (1). For this reason, the inconvenience of taking a daily supplementation and the cost, although low, would outweigh the potentially small benefit (2). Treatment with vitamin C does not impact the duration of cold symptoms (1).
Prevention of Common Cold
There is no evidence to suggest that vitamin C is effective at reducing the incidence of colds when taken on a regular basis in the general population (1,2,3). It shouldn't be recommended to patients for this reason. Regular supplementation may reduce the incidence of colds for patients who participate in extreme physical activity, such as marathon runners (1).
Severity of Cold Symptoms
Regular supplementation of vitamin C nor use at the onset of cold symptoms have been shown to decrease the severity of cold symptoms (1). It should not be recommended for this indication.
Bottom Line
Vitamin C should not be recommended to patients due to a lack of evidence suggesting that it has efficacy on the incidence, duration or severity of cold symptoms (1,2,3). However, if a patient participates in extreme physical activity, regular supplementation may reduce the incidence of colds (1).
If a patient is adamant about using vitamin C and the cost/convenience is not an issue, there are no safety concerns at doses <8g/day (1,2). No harm should come to the patient, so although we should not be recommending it, we do not need to discourage it's use.
References:
1. Hemila H, Chalker E, (2013). Vitamin C for preventing and treating the common cold. Cochran Database Systematic Review. 31;1:CD000980
2. e-CPS [Internet]. Ottawa (ON): Canadian Pharmacists Association; c2007 [updated 2012 July; cited 2014 March]. Vitamin C [product monograph]. https://www.e-therapeutics.ca/cps.showMonograph.action?newSearch=true&simpleIndex=brand_generic&simpleQuery=vitamin+C&brandExactMatch=false#m583200n00011
3. Lynch TP. Viral Rhinitis. In: Gray Jean, editor. e-Therapeutics+ [Internet]. Ottawa (ON): Canadian Pharmacists Association; c2007 [updated June 2013; cited 2014 Mar]. Available from: https://www.e-therapeutics.ca/tc.showChapter.action?documentId=c0037#c0037n00011
Duration of Cold Symptoms
A small amount of evidence exists for the supplementation of vitamin C to reduce the duration of cold symptoms (1). The evidence is not strong, the impact is not big, and the results were unable to be replicated (1). For this reason, the inconvenience of taking a daily supplementation and the cost, although low, would outweigh the potentially small benefit (2). Treatment with vitamin C does not impact the duration of cold symptoms (1).
Prevention of Common Cold
There is no evidence to suggest that vitamin C is effective at reducing the incidence of colds when taken on a regular basis in the general population (1,2,3). It shouldn't be recommended to patients for this reason. Regular supplementation may reduce the incidence of colds for patients who participate in extreme physical activity, such as marathon runners (1).
Severity of Cold Symptoms
Regular supplementation of vitamin C nor use at the onset of cold symptoms have been shown to decrease the severity of cold symptoms (1). It should not be recommended for this indication.
Bottom Line
Vitamin C should not be recommended to patients due to a lack of evidence suggesting that it has efficacy on the incidence, duration or severity of cold symptoms (1,2,3). However, if a patient participates in extreme physical activity, regular supplementation may reduce the incidence of colds (1).
If a patient is adamant about using vitamin C and the cost/convenience is not an issue, there are no safety concerns at doses <8g/day (1,2). No harm should come to the patient, so although we should not be recommending it, we do not need to discourage it's use.
References:
1. Hemila H, Chalker E, (2013). Vitamin C for preventing and treating the common cold. Cochran Database Systematic Review. 31;1:CD000980
2. e-CPS [Internet]. Ottawa (ON): Canadian Pharmacists Association; c2007 [updated 2012 July; cited 2014 March]. Vitamin C [product monograph]. https://www.e-therapeutics.ca/cps.showMonograph.action?newSearch=true&simpleIndex=brand_generic&simpleQuery=vitamin+C&brandExactMatch=false#m583200n00011
3. Lynch TP. Viral Rhinitis. In: Gray Jean, editor. e-Therapeutics+ [Internet]. Ottawa (ON): Canadian Pharmacists Association; c2007 [updated June 2013; cited 2014 Mar]. Available from: https://www.e-therapeutics.ca/tc.showChapter.action?documentId=c0037#c0037n00011