At the very first sign of cold symptoms, many people reach right for a bottle of vitamin C supplements. Vitamin C for the common cold is such a widely accepted treatment that we seek it out in lots of products, such as fortified juices, cough drops, and tea.
Vitamin C was first touted for the common cold in the 1970s. But despite its widespread use, experts say there's very little proof that vitamin C actually has any effect on the common cold.
Questions & Answers about the 2009–2010 Flu Season
What sort of flu season is expected this year?
Flu seasons are unpredictable in a number of ways, including the timing of
the beginning, severity, and length of the flu season.
This flu season (2009-2010), there are more uncertainties than usual because
of the emergence of a new 2009 H1N1
influenza virus (previously called "novel H1N1" or "swine flu") that has
caused the first influenza pandemic (global outbreak of disease) in more than
Vitamin C is an important vitamin and antioxidant that the body uses to keep you strong and healthy. Vitamin C is used in the maintenance of bones, muscle, and blood vessels. Vitamin C also assists in the formation of collagen and helps the body absorb iron.
Vitamin C is found naturally in vegetables and fruits, especially oranges and other citrus fruits. This key vitamin is also available as a natural dietary supplement in the form of vitamin C pills and vitamin C chewable tablets.
Can Vitamin C Prevent or Treat Cold Symptoms?
Vitamin C has been studied for many years as a possible treatment for colds, or as a way to prevent colds. But findings have been inconsistent. Overall, experts have found little to no benefit for vitamin C preventing or treating the common cold.
In a July 2007 study, researchers wanted to discover whether taking 200 milligrams or more of vitamin C daily could reduce the frequency, duration, or severity of a cold. After reviewing 60 years of clinical research, they found that when taken after a cold starts, vitamin C supplements do not make a cold shorter or less severe. When taken daily, vitamin C very slightly shorted cold duration -- by 8% in adults and by 14% in children.
But researchers found the most effect on people who were in extreme conditions, such as marathon runners. In this group, taking vitamin C cut their risk of catching a cold in half.
So what does all this mean?
The average adult who suffers with a cold for 12 days a year would still suffer for 11 days a year if that person took a high dose of vitamin C every day during that year.
For the average child who suffers about 28 days of cold illness a year, taking daily high-dose vitamin C would still mean 24 days of cold illness.
When vitamin C was tested for treatment of colds in 7 separate studies, vitamin C was no more effective than placebo at shortening the duration of cold symptoms.
Is Vitamin C Safe to Take?
In general, vitamin C is safe to take when ingested through food sources such as fruits and vegetables. For most people, taking vitamin C supplements in the recommended amounts is also safe. The RDA or recommended daily allowance is 90 mg for men and 75 mg for women. High doses of vitamin C (greater than 2000 milligrams per day for adults) may cause kidney stones, nausea, and diarrhea.
If you're unsure about taking vitamin C for colds, talk to your health care provider.
National Institute of Allergy and Infectious Diseases: "Common Cold."
PubMed: "Intake of Vitamin C and Zinc and Risk of Common Cold: A Cohort Study."
Mayo Clinic: "Cold Remedies: What Works, What Doesn't, What Can't Hurt."
Medscape: "Vitamin C May be Effective Against Common Cold. Primarily in Special Populations."
Douglas, R.M. The Cochrane Collaboration, 2007.
UptoDate: "The common cold in adults: Treatment and Prevention."
Medline Plus: "Flu."
Medline Plus: "Common Cold."