How to prevent a cold
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Effective Strategies to Prevent a Cold
Preventing the common cold is a topic of significant interest, especially during the colder months. Various studies have explored different methods and supplements to reduce the incidence, duration, and severity of colds. Here, we synthesize the findings from multiple research papers to provide a comprehensive overview of effective strategies to prevent a cold.
Andrographis Paniculata: Herbal Supplement for Cold Prevention
Andrographis paniculata, a plant used in traditional medicine, has shown promise in preventing colds. A study conducted with students during the winter season found that those who took Kan Jang tablets, made from Andrographis paniculata dried extract, had a significantly lower incidence of colds compared to those who took a placebo. After three months, the incidence of colds was 30% in the Kan Jang group versus 62% in the placebo group, indicating a relative risk reduction of 2.1 times1.
Vitamin C: Limited but Notable Benefits
Vitamin C has been extensively studied for its role in cold prevention and treatment. While routine high-dose vitamin C supplementation does not significantly reduce the incidence of colds in the general population, it has shown benefits in specific groups. For individuals exposed to severe physical stress, such as marathon runners and soldiers, vitamin C reduced the risk of developing a cold by 50%2 4. Additionally, regular vitamin C intake can reduce the duration of colds by 8% in adults and 14% in children2 4 9.
Zinc: Reducing Cold Duration
Zinc supplementation has been found to be effective in reducing the duration of colds. A systematic review of randomized controlled trials indicated that zinc could shorten the duration of cold symptoms by approximately 2.25 days when taken at the onset of symptoms3. This suggests that zinc can be a valuable supplement for managing cold symptoms and reducing the overall burden of the illness.
Garlic: Potential Preventive Effects
Garlic has been traditionally used for its antimicrobial properties. A study involving 146 participants found that those who took a garlic supplement daily for 12 weeks had significantly fewer colds compared to the placebo group (24 colds in the garlic group versus 65 in the placebo group)7. However, more research is needed to confirm these findings and establish garlic as a reliable preventive measure.
Ginseng: Mixed Evidence
Ginseng, particularly North American ginseng (Panax quinquefolius), has been studied for its potential to prevent colds. While some trials suggest that ginseng can reduce the total number of colds and shorten their duration, the evidence is not consistent across all studies. One trial reported a 25% reduction in the number of colds, and another found that ginseng shortened the duration of colds by 6.2 days10. However, the overall evidence remains inconclusive, and further research is warranted.
Conclusion
Preventing the common cold involves a combination of lifestyle practices and potentially beneficial supplements. Andrographis paniculata, vitamin C, zinc, and garlic have shown varying degrees of effectiveness in reducing the incidence, duration, and severity of colds. While vitamin C and zinc are more established in their benefits, Andrographis paniculata and garlic offer promising results that need further validation. Ginseng, although popular, requires more consistent evidence to be recommended universally. Adopting these strategies, especially during high-risk periods, can help mitigate the impact of the common cold.
Sources and full results
Most relevant research papers on this topic
Prevention of common colds with Andrographis paniculata dried extract. A Pilot double blind trial.
Kan Jang tablets, made from Andrographis paniculata dried extract, significantly decrease the incidence of common colds during the winter season.
RCT
Highly CitedVitamin C for preventing and treating the common cold.
Oral vitamin C in doses of 200 mg or more daily reduces the incidence, duration, and severity of common colds when used as continuous prophylaxis or after the onset of symptoms.
Meta-AnalysisHighly CitedZinc Supplementation Reduces Common Cold Duration among Healthy Adults: A Systematic Review of Randomized Controlled Trials with Micronutrients Supplementation
Zinc supplementation may potentially reduce common cold duration by 2.25 days in healthy adults, but other micronutrients may not prevent cold incidence or reduce symptom severity.
Systematic Review
Rigorous JournalVitamin C for preventing and treating the common cold.
Vitamin C supplementation fails to reduce common cold incidence in the general population, but may be beneficial for people exposed to brief periods of severe physical exercise or cold environments.
Meta-AnalysisStrategies for prevention of cold stress in the elderly.
Simple and efficient strategies for preventing cold stress in the elderly are crucial, considering whole body cooling, extremity cooling, convective cooling, conductive cooling, and airway cooling.
Garlic for the common cold.
Garlic may prevent common cold occurrences, but more clinical trial evidence is needed to validate this finding and claims of effectiveness rely on poor quality evidence.
Meta-Analysis
Very Rigorous JournalHighly CitedComplementary and alternative medicine for prevention and treatment of the common cold.
Vitamin C can be recommended for common cold prevention, while Echinacea purpurea and zinc lozenges show moderate evidence for treatment, while probiotics show no benefit for prevention or treatment.
Systematic ReviewVitamin C for preventing and treating the common cold.
Vitamin C supplementation does not reduce the incidence of colds in the general population, but may be useful for people exposed to brief periods of severe physical exercise.
Meta-AnalysisVery Rigorous JournalNorth American (Panax quinquefolius) and Asian Ginseng (Panax ginseng) Preparations for Prevention of the Common Cold in Healthy Adults: A Systematic Review
Ginseng preparations show insufficient evidence to reduce the incidence or severity of common colds, but may shorten the duration of colds or acute respiratory infections in healthy adults when taken preventatively for 8-16 weeks.
Systematic ReviewRigorous Journal