Ascorbic acid for the common cold. A prophylactic and therapeutic trial

Area of Science:

• Nutrition Science
• Public Health
• Clinical Research

Background:

• The common cold remains a prevalent illness with significant impact on productivity.
• Ascorbic acid (vitamin C) is widely believed to prevent or treat colds, though scientific evidence is debated.

Purpose of the Study:

• To investigate the efficacy of high-dose ascorbic acid supplementation in reducing the duration and severity of common colds.
• To assess the impact of ascorbic acid on cold incidence and dropout rates in a controlled trial.

Main Methods:

• A nine-month, double-blind, placebo-controlled study involving 311 National Institutes of Health employees.
• Participants received 1 gm of ascorbic acid or lactose placebo thrice daily, with an additional 3 gm daily at cold onset.
• Dropout rates were monitored, with dropouts defined as missing at least one month of study medication.

Main Results:

• Only 190 volunteers completed the study; dropout rates were higher in the placebo group (44%) than the ascorbic acid group (34%).
• Ascorbic acid demonstrated a minor influence, at best, on cold duration and severity.
• The observed effects could potentially be attributed to a breach in the double-blind condition.

Conclusions:

• High-dose ascorbic acid supplementation appears to have a limited effect on common cold symptoms.
• Further research is needed to confirm these findings and explore potential confounding factors like adherence and blinding integrity.