An analysis of Vitamin C trials on the common cold found that supplementation works to alleviate severe cold symptoms.
“Vitamin C has various effects on the immune system and the common cold can alter vitamin C metabolism such that vitamin C levels are temporarily decreased [in leucocytes, plasma, and urine]”
Key Points
- Vitamin C eased severity of cold symptoms by 15%
- Reduced duration of severe symptoms by 26%
- Minimized days spent absent from work and school
- Short term use may be beneficial for cold treatment
Impact of Vitamin C Reviewed in Meta-Analysis
A meta-analysis was conducted of 15 Vitamin C studies of orally administered doses of Vitamin C greater than 1g daily in individuals in good health at baseline (without a cold to start).
This focused on two outcomes:
- Severity of the common cold
- Symptoms
- Days indoors or absent
- Duration of severe stages
- Overall duration of the common cold
- Mild symptoms
“The duration of the trials ranged from 2 to 5 months, except the two trials that reported severe symptoms, which ran for about a week.”
Vitamin C Decreased Severity and Duration of Symptoms
The compared trials indicate that Vitamin C worked to decrease the intensity of severe cold symptoms overall.
“The pooled effect of ≥ 1 g/day vitamin C across all 15 comparisons indicates a highly significant 15% reduction in common cold severity.”
Comparison of the effect of Vitamin C in mild and severe expression of cold symptoms found a notable reduction in duration of severe symptoms.
“Over the 5 included trials, vitamin C decreased the duration of severe common cold outcomes by 26%.”
Vitamin C Reduced Days Confined to the House
Severe cold symptoms are a leading cause of absenteeism from work and school. Vitamin C works to alleviate these symptoms and decreases days confined to the house.
Multiple trials found that Vitamin C reduced the number of days needed to call out of work or keep children home from school.
“The larger Ludvigsson et al. trial with Swedish schoolchildren found that “absence from school” during common cold episodes was reduced in the vitamin C group by 18%.”
“The 1972 Anderson et al. trial with Canadian adults reported a 21% reduction in days “confined to house” per episode.”
This aligns with a previous review on Vitamin C that reported a decrease in the overall duration of a common cold
“In our Cochrane review on vitamin C and the common cold, we found that regular vitamin C supplementation of ≥ 0.2 g/day shortened the duration of colds by 9.4%.”
Conclusion
This analysis concluded that Vitamin C does decrease the severity of common cold symptoms and in turn reduces the number of days confined to the house.
“Over these three classes of outcomes, we found a 15% average decrease in the severe forms of the common cold in people being administered vitamin C.”
“We found that vitamin C had a significant effect on the duration of severe symptoms… there was strong evidence of a 26% reduction in the more severe measures of common cold.”