Professor Brian Ratcliffe from Robert Gordon University, in Aberdeen, says that million of consumers are wasting their time and money by taking vitamin supplements.
"I couldn't tell you what my personal biological requirement is for any vitamin. All I can do is use the population-based evidence," he said in a speech at the British Festival of Science at the University of Surrey in Guildford.
He added that consuming many vitamins could easily increase their levels in the body and can prove dangerous. For example excess levels of vitamin A can lead to headaches and nausea and even osteoporosis.
"People who take multivitamin supplements are probably just wasting their money and boosting the profits of vitamin companies. With the sort of multivitamin mix that's readily available, if you're taking one of those on top of your normal vitamin intake you're unlikely to push yourself beyond safe levels. But there is a chance you could be dabbling in areas where there is a potential for harm," Prof Ratcliffe added.