A recent and well-publicized review of vitamin C by the Cochrane
Collaboration has resulted in much misguided discussion in the popular
There are important facts that emerge from the review. At least
30 controlled clinical trials (many double-blind and placebo-controlled)
involving a total of over 11,000 participants have been conducted.
Vitamin C in doses ranging from 200 mg to 2,000 mg per day (the
dosage range used in a large majority of the studies) reduces the
duration of colds by 7% for adults and 15% for children. The data
indicates that there is a normal dose-response relationship. Vitamin
C is more effective the higher the dose. The most effective doses
are far more than 2,000 mg/day. Exclusion of higher-dose studies
because they were not placebo controlled is not justified.
The effectiveness of vitamin C against colds could well provide
a justification for the Food and Nutrition Board raise the RDA of
vitamin C. The primary reason for reluctance to take this action
is because it would, for most persons, require vitamin C supplementation
or a plant-based diet, or both.
The results of a trial conducted in Japan have just been published(2). It is a double blind, 5-yr randomized controlled trial involving
439 participants. The supplemented groups received either 50 or
500 mg/day of vitamin C. The study indicates that vitamin C supplementation
does indeed reduce the frequency of colds. The probability of suffering
from 3 colds over the course of the study period was reduced by
66% in the group supplementing at 500 mg/day.
For decades, numerous reports from physicians have provided ample
clinical confirmation about the effectiveness of vitamin C for treating
the common cold(3-5). Orthomolecular physicians have worked with
their patients to optimize the dose and have confirmed the conclusions
reached by the authors of the Cochrane report that higher doses
of vitamin C are more effective(6). They have concluded that patients
will benefit by taking as much vitamin C as they can tolerate, and
encourage patients to balance the benefits of fighting off a cold
sooner with the drawback of intestinal discomforts. These discomforts
are harmless and last at most for a few hours. Epidemiological studies
associate long-term vitamin C supplementation with health benefits
and increased longevity. A 23-year review of collected US poison
control center annual reports(7) tells a remarkable and largely
ignored story: vitamin C is extraordinarily safe.
We are confident that the RDA/DRI for vitamin C will eventually
be raised. It is just a matter of time.
- Douglas RM, Hemilä H, Chalker E, Treacy B. Vitamin C for
preventing and treating the common cold. Cochrane Database of
Systematic Reviews, 2007. Issue 3. http://www.mrw.interscience.wiley.com/cochrane/clsysrev/articles/CD000980/abstract.html
- Sasazuki S, Sasaki S, Tsubono Y, Okubo S, Hayashi M, Tsugane
S. Effect of vitamin C on common cold: randomized controlled trial.
European Journal of Clinical Nutrition, 2006. 60(1), 9-17.
- Cathcart RF. Vitamin C, titrating to bowel tolerance, asascorbemia
and acute induced scurvy. Medical Hypotheses, 1981. 7:1359-1376.
- Klenner FR. Significance of high daily intake of ascorbic acid
in preventive medicine. Megascorbic therapies: Vitamin C in medicine.
Vol 1, 1. http://www.vitamincfoundation.org/news.htm See also:
Saul AW. Hidden in plain sight: The pioneering work of Frederick
Robert Klenner, M.D.. J Orthomolecular Med, 2007. Vol 22, No 1,
p 31-38. http://www.doctoryourself.com/klennerbio.html
- Smith LH, Klenner FR. Clinical guide to the use of vitamin
- Levy, Thomas E. Curing the Incurable: Vitamin C, Infectious
Diseases, and Toxins. Livon Books, 2002. ISBN-10 1401069630
Linus Pauling defined orthomolecular medicine as "the treatment
of disease by the provision of the optimum molecular environment,
especially the optimum concentrations of substances normally present
in the human body." Orthomolecular medicine uses safe, effective
nutritional therapy to fight illness. For more information: http://www.orthomolecular.org
The peer-reviewed Orthomolecular Medicine News Service is a non-profit
and non-commercial informational resource.
Editorial Review Board:
Abram Hoffer, M.D., Ph.D.
Harold D. Foster, Ph.D.
Bradford Weeks, M.D.
Carolyn Dean, M.D., N.D.
Erik Paterson, M.D.
Thomas Levy, M.D., J.D.
Steve Hickey, Ph.D.