Trial finds supplementation with vitamin C associated with lower risk of common cold

April 7, 2020

A randomized, double-blind trial reported on March 5, 2020 in BMJ Military Health resulted in a lower risk of contracting the common cold among members of the military in the Republic of Korea who received daily vitamin C supplements.

Like many of the world’s military training centers, those in South Korea have a high incidence of communicable respiratory diseases.

The trial included 1,444 soldiers enlisted in the Korea Army Training Center. The participants’ age averaged 21.7 years. For a period of 30 days, 695 participants received 2000 milligrams of vitamin C three times per day while the remainder received a placebo.

Subjects who received vitamin C had a 20% lower risk of acquiring a cold compared to the placebo group. The protective effect of vitamin C was stronger among those who described themselves as having never smoked.

“To our best knowledge, this is the second largest randomized, double-blind, placebo-controlled trial after Dahlberg et al’s study in 1944 to assess the benefit of vitamin C intake for preventing respiratory infections,” authors Tae Kyung Kim of Yonsei University in Seoul, South Korea and colleagues announced.

In their discussion of the findings, they remarked that vitamin C boosts immunity by improving white blood cell function against viruses. It also has an antihistamine action that helps reduce cold symptoms.

“Although additional studies are needed, such as the evaluation of economic feasibility, before vitamin C can be distributed to training soldiers, our results can provide the basis to push evidence-based military health and medical policy,” they write. “Vitamin C should be distributed to prevent non-combat loss of soldiers during basic military training.”


Apply What You've Learned: Common Cold

  • According to the U.S. National Institutes of Health, there are over 200 different common cold viruses; among which up to 35% are rhinoviruses.1
  • In his book, Vitamin C and the Common Cold, Dr. Pauling presented an analysis of controlled, published trials of ascorbic acid in which several had determined with statistical significance at the confidence level of 95% or higher that vitamin C has value in reducing common cold incidence and severity.2
  • While vitamin C’s ability to prevent colds is still the subject of controversy, an analysis of studies that included 598 participants who engaged in brief periods of strenuous physical activity, including runners, skiers and soldiers on subarctic exercises, found a 52% reduction in the risk of acquiring a cold in association with vitamin C supplementation in comparison with a placebo.3
  • In addition to vitamin C, there is evidence that zinc and echinacea may be helpful in the treatment of common colds. Furthermore, supplementing with vitamin D may be useful to remain healthy during cold season.4


  1. Wein, Harrison. “Understanding a Common Cold Virus.” National Institutes of Health. 2009 13 April.
  2. Pauling L. JAMA. 1971 Apr 12;216(2):332.
  3. Hemilä H et al. Cochrane Database Syst Rev. 2013 Jan 31;(1):CD000980.
  4. Rondanelli M et al. Evid Based Complement Alternat Med. 2018 Apr 29;2018:5813095.

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