I was doing so well, but they finally got me too – rhinoviruses, the usual cause of common cold. So here I am, lying in bed, sneezing louder than my neighbour practicing piano in the middle of the night. This weekend I ventured outside just once – to get some orange juice, because I had been craving it so much. Orange juice = vitamin C, so such cravings make sense, don’t they? Well, let’s see what the data says.
I don’t know if it’s just my family, but whenever I was sick as a child, I was forced to take tons of vitamin C in various forms. This doesn’t surprise me at all as the double Nobel prize winner Linus Pauling himself claimed that high doses of ascorbic acid (the fancy name for vitamin C) help prevent and fight the common cold. It turns out that even Nobel prize winners aren’t infallible.
In 2005 two scientists Robert M. Douglas and Harri Hemilä published a short review of scientific trials seeking to determine the influence of high doses of vitamin C (at least 200 mg per day) on common cold immunity, its duration and severity. They analysed 23 placebo-controlled studies with thousands of participants, which is a group big enough to produce medically significant (don’t confuse with statistically significant, more on this topic soon) results. What did they find?
There’s no evidence that taking vitamin C helps in preventing or figting the cold in any way apart from possibly making the duration of symptoms slightly shorter. The only exception are people about to be exposed to extreme physical stress, such as marathon runners (very very exhausting) or anyone about to spend some time in Siberia (very very cold). Which means that buying vitamin C tablets is just a waste of money and time.
What about my orange juice cravings though? My personal theory is that I’m just used to taking vitamin C when sick. And even though there’s no scientific evidence that this will help me fight the cold symptoms, the placebo effect can be very powerful. So I’ll enjoy my juice anyway, I guess it won’t hurt.
Stay healthy and informed!