Linus Pauling is the only person to ever receive two unshared Nobel Prizes. He also believed that high doses of Vitamin C cured a whole host of ailments. He’s proof that even the most intelligent among us can fall for pseudoscientific BS.
Vitamin C is a water-soluble vitamin that humans are unable to synthesise, which is why we need to obtain is from our diet. Adults are recommended to consume 40mg per day, which can come from foods like oranges, peppers, broccoli, strawberries, and potatoes. It acts as an antioxidant, an enzyme cofactor, it plays a role in collagen synthesis, and is found in high amounts in immune cells.
Since the 1970s the myth of vitamin C curing the common cold has prevailed, leading to many of us even now reaching for those chewy pills (or the baobab powder if you’re really ‘cool alternative’). But based on what evidence? I’m so glad you asked…
That was easy.
When 29 trials, with over 10,000 participants in total, were analysed, it showed that vitamin C didn’t prevent the onset of the common cold. At best, higher doses of vitamin C (above 200mg/day) may reduce the duration of a cold by about 8%, which in the context of a 3 day cold is still almost 3 days (wow), but doesn’t reduce the severity of the symptoms.
There’s only one situation where vitamin C has been shown to be effective at preventing colds, and that is “when consumed regularly by athletes training in subarctic conditions”. I’m going to hazard a guess that that won’t apply to 99% of people reading this. If you are an athlete training in subarctic conditions then seriously well done (but also: why?!).
Interestingly, when people knew they were taking a vitamin tablet rather than a placebo, they reported fewer colds, whereas when they didn’t know what they were taking there was no difference. Just goes to show how powerful the placebo effect can be!
While We’re At It…
There is no evidence to suggest that vitamin C supplementation:
- prevents cancer (lung, prostate, colorectal, or breast)
- treats cancer
- reduces the risk of cardiovascular disease
- prevents stroke
- treats arthritis
The Vitamin Myth
Vitamin C is just one example of many, where vitamin supplementation is believed to improve or ‘optimise’ health. If you are suffering from a vitamin deficiency or can’t obtain enough from your diet then of course a supplement is recommended. But if you’re eating your 5-a-day and have a generally balanced diet, then taking vitamin supplements can actually do more harm than good. In some cases, supplementation can lead to increased risk of death – ironic, considering the marketing claims.
As usual the message is simple: if it sounds too good to be true it probably is, and vitamin C definitely isn’t a panacea.