Observe the world around you and reflect on … Habits, ‘truth’ or other phenomenon that have grown from tradition or other source (e.g. family, disciplinary or cultural) and become part of our ‘practice’ that may or not have any evidence base for the practice.
For half of last week I was inflicted with all the horrible symptoms of the common cold. The first thing I did when I felt the symptoms start was visit a chemist and buy some cold and flu tablets. The second thing I did was visit a health food store to buy a large supply of Vitamin C tablets to assist with the recovery from this virus, because from as far back as I remember, I have been told that Vitamin C helps to fight off colds. As a child, I used to enjoy taking Vitamin C for its sugary qualities, rather than any perceived medicinal qualities. This caused me to question what type of scientific evidence supported this claim of Vitamin Cs supposed healing benefits, or was it something that I was told from a young age and just chose to continue believing? Was my belief that Vitamin C reduced the severity and duration of colds enough to make me think that it worked, despite it having very little effect at all, or was there scientific evidence supporting its health benefits?
This practice appears to have gained widespread attention from Linus Pauling’s book from the 1970s, Vitamin C and the Common Cold, which claimed that Vitamin C could significantly decrease the incidence of the common cold. A controlled study undertaken at the time indicated that taking Vitamin C in mega-doses before and after the onset of cold symptoms relieved and prevented symptoms in the test group compared to the control group. This in turn created a widespread belief that consuming more vitamin C reduces the risk of catching a cold and its severity.
While widespread research has been undertaken on this topic, there seems to be conflicting evidence over the validity of the results. Researchers at the National Centre for Epidemiology and Population Health in the ACT undertook an extensive investigation into twenty-nine trial comparisons that have been undertaken over the years involving 11,077 study participants. Their findings determined that taking mega-doses of Vitamin C to reduce the duration and severity of colds is not justifiable for community use. Trials where Vitamin C (up to 4 grams daily) were consumed as treatment at the start of colds did not show any benefit to the participants. However, trials where 8 grams of Vitamin C were consumed as treatment at the start of colds were shown to have some benefits.
To put this into perspective, each tablet within the bottle of Vitamin C that I purchased contains 500mg of Vitamin C. Therefore, to see any real benefit from the treatment of Vitamin C, one would have to consume 16 tablets at the onset of symptoms. The recommended daily intake of Vitamin C for healthy adults is anywhere between 30 and 90 mg. Excess consumption of Vitamin C has been found to result in neglible absorption and can result in it being excreted out of the body.
Excessive intake of Vitamin C has also been linked to indigestion and diarrhoea; the dosage rate which can vary from person to person. What may also be unknown is that ascorbic acid, which is a form of Vitamin C, is included in some cold tablets, so by taking these cold and flu tablets to alleviate symptoms, you are already ingesting a form of Vitamin C.
From the research conducted above, the findings also indicated that persons involved in brief periods of severe physical exercise and/or cold environments (such as athletes or soldiers) could benefit from using Vitamin C as a treatment and prevention against common colds.
While there are benefits to including Vitamin C supplements in ones daily intake, it appears that this treatment option for the common cold has perhaps been over-emphasised to the general public, given the dose that one would have to consume to see any real benefits in the prevention or minimisation of the severity and duration of colds.
References
- Wikipedia, 2012, Vitamin C and the Common Cold, viewed 25 March 2012, http://en.wikipedia.org/wiki/Vitamin_C_and_Common_Cold
- Douglas RM, Hemila H, Chalker E, Treacy B, 2004, Vitamin C for preventing and treating the common cold, Cochrane Database Syst Rev. 2004 - PubMed – NCBI, viewed 26 March 2012, http://www.ncbi.nlm.nih.gov/pubmed/15495002