Vitamin Supplements and Cold Prevention
Scenario: It’s winter and you’re working in a family practice office. Many patients are coming in with runny noses and general malaise. Brenda, a 35-year-old working mother comes in for a checkup and says, “I’m so busy between work and home that I definitely don’t have time to get sick! Can those zinc or vitamin C pills I hear about prevent colds?”
Clinical Question:
Do zinc or vitamin C supplementation pills prevent and/or treat the common cold?
PICO Question:
Can zinc or vitamin C pills prevent and/or treat the common cold in adult females.
P: adult, female
I: zinc and/or vitamin C supplement
C: no intake of zinc and/or vitamin C (vitamin supplements)
O: cold prevention, symptom relief, decreased cold duration, URI prevention
Search Strategy:
Searched Terms: ‘vitamin c cold prevention’; ‘zinc cold prevention’; zinc cold treatment, ‘vitamin C cold treatment’; ‘URI prevention’; ‘URI treatment’
Database and Articles Returned:
PubMed (via ‘best match’) filter: 201→ 3 articles chosen
Cochrane → Review → 84 → 1 article chosen
Filters: systematic review AND meta-analysis→ 37 results (on PubMed) → 1 article chosen
Selection Methods (what criteria determined which articles to include in this CAT):
→ See grid below
Adult pt supplementing with Vitamin C
Adult pt supplementing with Zinc
Compared to no intervention / placebo
Common Cold prevention
| P | I | C | O |
| adult | Zinc supplement | Placebo | Cold prevention |
| female | Vitamin C supplement | No intervention | Symptom relief |
| Middle aged | Decreased duration | ||
| URI prevention |
Articles Chosen for Inclusion:
Nahas R, Balla A.
Can Fam Physician. 2011 Jan;57(1):31-6. Review.
PMID: 21322286
Abstract
OBJECTIVE:
To review the evidence supporting complementary and alternative medicine approaches to treatment and prevention of the common cold in adults.
QUALITY OF EVIDENCE:
MEDLINE, EMBASE, and the Cochrane Database of Systematic Reviews were searched from January 1966 to September 2009 combining the key words common cold or influenza with echinacea, garlic, ginseng, probiotics, vitamin C, and zinc. Clinical trials and prospective studies were included.
MAIN MESSAGE:
For prevention, vitamin C demonstrated benefit in a large meta-analysis, with possibly increased benefit in patients subjected to cold stress. There is inconsistent evidence for Asian ginseng (Panax ginseng) and North American ginseng (Panax quinquefolius). Allicin was highly effective in 1 small trial. For treatment, Echinacea purpurea is the most consistently useful variety; it was effective in 5 of 6 trials. Zinc lozenges were effective in 5 of 9 trials, likely owing to dose and formulation issues. Overall, the evidence suggests no benefit from probiotics for prevention or treatment of the common cold.
CONCLUSION:
Vitamin C can be recommended to Canadian patients for prevention of the common cold. There is moderate evidence supporting the use of Echinacea purpurea and zinc lozenges for treatment. Ginseng and allicin warrant further research.
Sasazuki S, Sasaki S, Tsubono Y, Okubo S, Hayashi M, Tsugane S.
Eur J Clin Nutr. 2006 Jan;60(1):9-17.
PMID: 16118650
OBJECTIVE:
To investigate the relationship between the common cold and vitamin C supplementation.
DESIGN:
A double-blind, 5-year randomized controlled trial.
SETTING:
A village in Akita prefecture, one of the regions in Japan with the highest mortality from gastric cancer.
SUBJECTS:
Participants in annual screening programs for circulatory diseases conducted under the National Health and Welfare Services Law for the Aged, and diagnosed as having atrophic gastritis. Of the 439 eligible subjects, 144 and 161 were assigned to receive 50 or 500 mg of vitamin C, respectively, after protocol amendment. During the supplementation phase, 61 dropped out, and 244 completed the trial.
INTERVENTION:
Daily vitamin C supplementation of 50 mg (low-dose group) or 500 mg (high-dose group).
RESULTS:
Total number of common colds (per 1000 person-months) was 21.3 and 17.1 for the low- and high-dose groups, respectively. After adjustment for several factors, the relative risks (95% confidence interval (CI)) of suffering from a common cold three or more times during the survey period was 0.34 (0.12-0.97) for the high-dose group. No apparent reduction was seen for the severity and duration of the common cold.
CONCLUSION:
A randomized, controlled 5-year trial suggests that vitamin C supplementation significantly reduces the frequency of the common cold but had no apparent effect on the duration or severity of the common cold. However, considering several limitations due to protocol amendment, the findings should be interpreted with caution.
Maggini S, Beveridge S, Suter M.
J Int Med Res. 2012;40(1):28-42. Review.
PMID:22429343
Background: Vitamin C and zinc play important roles in nutrition, immune defence and maintenance of health. Intake of both is often inadequate, even in affluent populations. The common cold continues to place a great burden on society in terms of suffering and economic loss.
Methods: After an overview of the literature on the effects of the separate administration of either vitamin C or zinc against the common cold, this article presents data from two preliminary, double-blind, randomized, placebo-controlled trials, conducted with a combination of 1000 mg vitamin C plus 10 mg zinc in patients with the common cold.
Results: In both studies, a nonsignificant reduction of rhinorrhoea duration (range 9 – 27%) was seen. In pooled analyses of both studies (n = 94), vitamin C plus zinc was significantly more efficient than placebo at reducing rhinorrhoea over 5 days of treatment. Furthermore, symptom relief was quicker and the product was well tolerated.
Conclusion: In view of the burden associated with the common cold, supplementation with vitamin C plus zinc may represent an efficacious measure, with a good safety profile, against this infectious viral disease.
- Hemilä H, Chalker E. Vitamin C for preventing and treating the common cold. Cochrane Database of Systematic Reviews 2013, Issue 1. Art. No.: CD000980. DOI:10.1002/14651858.CD000980.pub4.
Background: Vitamin C (ascorbic acid) for preventing and treating the common cold has been a subject of controversy for 70 years.
Objectives: To find out whether vitamin C reduces the incidence, the duration or severity of the common cold when used either as a continuous regular supplementation every day or as a therapy at the onset of cold symptoms.
Search methods: We searched CENTRAL 2012, Issue 11, MEDLINE (1966 to November week 3, 2012), EMBASE (1990 to November 2012), CINAHL (January 2010 to November 2012), LILACS (January 2010 to November 2012) and Web of Science (January 2010 to November 2012). We also searched the U.S. National Institutes of Health trials register and WHO ICTRP on 29 November 2012.
Selection criteria: We excluded trials which used less than 0.2 g per day of vitamin C and trials without a placebo comparison. We restricted our review to placebo-controlled trials.
Data collection and analysis: Two review authors independently extracted data. We assessed ‘incidence’ of colds during regular supplementation as the proportion of participants experiencing one or more colds during the study period. ‘Duration’ was the mean number of days of illness of cold episodes.
Main results: Twenty-nine trial comparisons involving 11,306 participants contributed to the meta-analysis on the risk ratio (RR) of developing a cold whilst taking vitamin C regularly over the study period. In the general community trials involving 10,708 participants, the pooled RR was 0.97 (95% confidence interval (CI) 0.94 to 1.00). Five trials involving a total of 598 marathon runners, skiers and soldiers on subarctic exercises yielded a pooled RR of 0.48 (95% CI 0.35 to 0.64). Thirty-one comparisons examined the effect of regular vitamin C on common cold duration (9745 episodes). In adults the duration of colds was reduced by 8% (3% to 12%) and in children by 14% (7% to 21%). In children, 1 to 2 g/day vitamin C shortened colds by 18%. The severity of colds was also reduced by regular vitamin C administration. Seven comparisons examined the effect of therapeutic vitamin C (3249 episodes). No consistent effect of vitamin C was seen on the duration or severity of colds in the therapeutic trials. The majority of included trials were randomised, double-blind trials. The exclusion of trials that were either not randomised or not double-blind had no effect on the conclusions.
Authors’ conclusions: The failure of vitamin C supplementation to reduce the incidence of colds in the general population indicates that routine vitamin C supplementation is not justified, yet vitamin C may be useful for people exposed to brief periods of severe physical exercise. Regular supplementation trials have shown that vitamin C reduces the duration of colds, but this was not replicated in the few therapeutic trials that have been carried out. Nevertheless, given the consistent effect of vitamin C on the duration and severity of colds in the regular supplementation studies, and the low cost and safety, it may be worthwhile for common cold patients to test on an individual basis whether therapeutic vitamin C is beneficial for them. Further therapeutic RCTs are warranted.
Takkouche B, Regueira-Méndez C, García-Closas R, Figueiras A, Gestal-Otero JJ.
Epidemiology. 2002 Jan;13(1):38-44.
PMID: 11805584
Abstract: To examine whether intake of vitamin C and zinc is associated with a decrease in the risk of a common cold, we analyzed data from a cohort study carried out in a population of 4,272 faculty and staff from five Spanish universities. Participants were 21–65 years of age, were full-time workers at those universities, and did not have antecedents of asthma or chronic obstructive pulmonary disease. Daily intake of vitamin C and zinc was assessed at baseline by means of a food frequency questionnaire of which the validity and reproducibility were determined in a sample of the population. Subjects were traced for 1 year to detect episodes of common cold, the diagnosis of which was based on symptoms and was validated by additional clinical signs. We detected 1,667 cases of common cold in 79,240 person-weeks of follow-up. Intake of vitamin C and zinc was not related to the occurrence of common cold. Compared with the first quartile of intake, women in the fourth quartile of vitamin C intake showed an adjusted incidence rate ratio of 1.0 (95% CI = 0.7–1.3), and for zinc intake this figure was 1.1 (95% CI = 0.8–1.5). The incidence rate ratios for men in the fourth quartile were 1.1 (95% CI = 0.8–1.4) for vitamin C and 1.3 (95% CI = 0.9–1.8) for zinc.
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