A further reason to try to avoid looking for the magic results of mega doses of vitamins is that they can have toxic effects. Some people think that because some is good, more is better, which is not necessarily the case. This is particularly true with vitamins that are fat soluble like vitamin A and will be stored up in the liver. This can eventually reach toxic levels and can damage the liver. Vitamin C will just be secreted with the urine but it can cause diarrhoea at levels of 2000 mg a day, which is lower than the amount many people take to stave off colds.
Taking vitamins and food supplements is neither good nor bad but unnecessary for most of us. There is a lot to be said for saving the money and splashing out once in a while on a nutritious and delicious well-balanced meal at a ritzy restaurant instead.