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.
Person to Person
The main way that influenza viruses are thought to spread is from person to
person in respiratory droplets of coughs and sneezes. (This is called "droplet
spread.") This can happen when droplets from a cough or sneeze of an infected
person are propelled through the air and deposited on the mouth or nose of
people nearby. Influenza viruses may also be spread when a person touches
respiratory droplets on another person or an object and then touches their own
mouth or nose (or...
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."