Vitamin C for the Common Cold

At the very first sign of cold symptoms, many people reach for Vitamin C, whether in supplements, juices, cough drops, tea, or other forms.

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.

What Is Vitamin C?

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 help prevent colds. But findings have been inconsistent. Overall, experts have found little to no benefit from vitamin C for 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 shortened cold duration -- by 8% in adults and by 14% in children.

So what does all this mean?

According to this research, the average adult who suffers with a cold for 12 days a year would still suffer for about 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 likely mean about 24 days of cold illness.

When vitamin C was tested for treatment of colds in 7 separate studies, it was found to be no more effective than placebo at shortening the duration of cold symptoms.

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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.

WebMD Medical Reference Reviewed by Jennifer Robinson, MD on January 20, 2017

Sources

SOURCES:
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" and "Common Cold."

National Institutes of Health.
 

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