Vitamin C: What it Can and Cannot Do

We have known about vitamin C since the 17th century, when it was found that a lack of fresh fruit and vegetables caused scurvy in sailors. But in the last few decades, vitamin C has come to be regarded as something of a cure-all. Vitamin C's advocates – in particular, those working for the vitamin industry – have claimed that vitamin C can do everything from preventing colds, to eliminating cancers and prolonging life.

So what is the truth about this most popular of all supplements?

What Vitamin C Does

Vitamin C helps to stabilise the collagen that is synthesised within our bodies. Without vitamin C, the collagen that binds our bodies together begins to break down. This is the effect of scurvy. Scurvy can lead to liver spots and bleeding, then to suppurating wounds and loss of teeth, and eventually death.

For similar reasons, it is thought that for athletes and sports people, additional vitamin C may help in repairing connective tissue damage. In weight lifting, particularly, where the building of muscle is one of the primary goals, extra vitamin C can be of considerable benefit to recovery.

Among smokers, too, it has been found that a lack of vitamin C can lead to a range of lung diseases that non-smokers are unlikely to contract.

Vitamin C is also thought to be a powerful antioxidant, protecting the body against free radicals that are thought to cause cell damage. It is possible that antioxidants might help to prevent some cancers and heart disease, though so far the evidence is inconclusive. Our understanding of oxidants and antioxidants is still limited; it is not even clear whether these oxidants are a cause of disease, or simply an effect.

Vitamin C Myths

Unsurprisingly, suggestions that vitamin C can prevent strokes, heart attacks and cancer have not yet been proved in control trials. More surprisingly, perhaps, a recent study suggested that vitamin C has absolutely no effect in preventing the common cold. This flies in the face of the contemporary belief that downing thousands of milligrams of vitamin C will ward off the coughs and sneezes. An important consideration, when the British public spends millions every year on vitamin supplements intended to do that very thing!

Remember: When extraordinary claims are made about any product, it is wise to approach that product with a healthy degree of scepticism. As much as we'd like to believe that there is a “magic pill” that will make us live for ever, the truth is that, at present, no such thing exists.

Vitamin C and You

In Britain, the recommended daily allowance (RDA) for vitamin C is 40mg. This is a fraction of the RDA of 3000mg recommended by the Vitamin C Foundation, an organisation with close ties to the vitamin industry. Many health organisations, however, recommend that you should not take more than 2000mg per day.

For serious athletes and weightlifters, a figure of 2000mg vitamin C per day is the figure commonly suggested. For everyone else, such high concentrations are not necessary: Excess vitamin C in your system will simply be passed out through your digestive tract. Luckily, vitamin C has very low toxicity. This means that it is very difficult to overdose, and that taking a large amount is unlikely to lead to complications much beyond diarrhoea or nausea.

There will be plenty of people who will continue to take large amounts of vitamin C “just to be on the safe side”, regardless of the scientific evidence. But knowing what you can realistically expect vitamin C to do for you is vital, as the claims regarding this benign yet controversial substance become ever more fantastic.