Overdosing on Vitamin C
While shopping for my Christmas spiced beef in Cork’s English Market this morning, I couldn’t help but overhear a conversation between two rather elderly ladies discussing the nutritional benefits of a glass of Stout and milk, and the health protective effects of a daily vitamin C tablet. While the former has clear nutritional content, although from childhood memories the taste leaves a lot to be desired, the latter has little benefit for anyone with a reasonably well balanced diet. When I enquired of the ladies why they were taking vitamin C, I was told in no uncertain terms that it ‘protected against cancer, warded off colds and flu and gave a daily pep to their lives’. This is not an unusual response as quite a significant percentage of the population are quite happy to pop a daily tablet of vitamin C in the mistaken belief that it somehow has all sorts of vague health protective effects. So what exactly are the benefits of vitamin C, how much do we need and perhaps more importantly why are the above views so prevalent among the Irish population?
The RDA of vitamin C is 75-90mg depending on whether you are a male or female and you really don’t see individuals with scurvy (vitamin C deficiency) these days so widespread in this vitamin in the diet. Most vegetables have lots of vitamin C and unless you want to eat a pure meat diet then you are not going to suffer from a deficiency in this vitamin.
Proper controlled trials have showed no benefits of vitamin C in relation to several cancers. Similar trials have also shown that there are no protective effects against the common cold of flu. So why then do people persist in taking daily doses of vitamin C that are commonly 10 times the RDA and are largely excreted? The answer of course is lack of knowledge and the blame for that in part lies with us scientists who have failed to convey the appropriate information to the general public. This coupled with subtly misleading advertising also encourages people to buy vast quantities of this vitamin on an annual basis. I believe there is a real need in this country to educate the public in simple matters of science so that they don’t as in this case waste their hard earned money on buying into the pretty much unproven health claims for this particular vitamin. Yet I don’t see this being done! Maybe 2010 is the year when we as scientists make this effort.