Vitamin C supplements
Vitamin C is a vitamin found in fresh fruit and some vegetables, especially citrus fruits. Vitamin C is also available as a dietary supplement. Experts recommend getting vitamin C from a diet high in fruits and vegetables rather than taking vitamin C supplements.
In the past, vitamin C was used for preventing and treating scurvy. This was once a common condition affecting people who spent long periods of time on ships, with little or no fresh fruit and vegetables to eat.
Vitamin C plays an important role in keeping your skin, bones and connective tissue healthy, is involved in wound healing, and helps your body absorb iron from your food.
Does vitamin C help prevent or treat a cold?
Despite being commonly used, vitamin C supplements have not been shown to prevent colds or to give reliable effects in treating the symptoms of a cold.
No clinical trials have yet tested the effect of vitamin C on colds in children.
More research is needed to find out whether vitamin C can prevent or help treat pneumonia. Vitamin C supplements may help people with pneumonia who have low blood levels of vitamin C.
What are the side effects of vitamin C?
Most people won’t experience any side effects if vitamin C is taken by mouth (orally) at the manufacturer’s recommended daily doses.
However, taking more than 2000 mg of vitamin C every day may cause side effects including kidney stones and diarrhoea. People who have, or have had, a kidney stone should not take more than 1000 mg a day, because this greatly increases the chance that kidney stones will recur.
Who can I ask about side effects?
If you’re concerned that you or someone in your care may have had side effects related to a medicine, seek medical advice. To report and discuss possible side effects, call the Adverse Medicines Events Line on 1300 134 237 from anywhere in Australia (Monday–Friday, 9am–5pm).
Tell your doctor about all the medicines you are taking
It is important that you tell your health professional about all the medicines you or anyone in your care is taking — including prescription, over-the-counter and complementary medicines (‘herbal’ or ‘natural’ medicines and vitamin and mineral supplements). This is because all medicines, including herbal and natural medicines, can cause side effects and may interact with other medicines. The benefits and risks of herbal and natural medicines may not have been tested.
Phone for medicines information
Call the NPS Medicines Line on 1300 MEDICINE (1300 633 424) to get information about your prescription, over-the-counter and complementary medicines (‘herbal’ or ‘natural’ medicines and vitamin and mineral supplements) from a pharmacist. Your call will be answered by healthdirect Australia.
- Hemilä H, Chalker E, Douglas B. Vitamin C for preventing and treating the common cold. Cochrane Database Syst Rev 2007;(3):CD000980.pub3. onlinelibrary.wiley.com/doi/10.1002/14651858.CD000980.pub3/abstract (accessed 21 March 2012).
- Hemilä H, Louhiala P. Vitamin C for preventing and treating pneumonia. Cochrane Database Syst Rev 2007;(3):CD005532.pub2. onlinelibrary.wiley.com/doi/10.1002/14651858.CD005532.pub2/abstract (accessed 21 March 2012).
- National Centre for Complementary and Alternative Medicine. The flu, the common cold, and complementary health practices: what the science says. NCCAM Clin Digest; February, 2012. nccam.nih.gov/health/providers/digest/coldflu-science.htm (accessed 21 March 2012).
- National Institutes of Health. Vitamin C (ascorbic acid). MedlinePlus; July 2011. www.nlm.nih.gov/medlineplus/druginfo/natural/1001.html (accessed 21 March 2012).