Vitamins and dietary supplements are a waste of money for most people

The person is Grace Wade.

According to updated recommendations from the US Preventive Services Task Force, it is not certain whether supplements help protect against cancer or cardiovascular disease in most adults.

Half of the US population takes supplements. They are seen as a way to fill gaps in their diet.

This perception is challenged by the new guidelines. 16 independent medical experts are part of the task force that gives guidance on preventive health measures. 54 of the 84 studies it reviewed were published after the group last issued advice on supplements.

Michael Barry, the organisation's vice chair, told New Scientist that they couldn't find enough evidence to recommend against the use of vitamins and minerals.

Read more: The truth about supplements: do they work and should you take them?

The task force advised against taking vitamins. It found that there was no benefit to taking vitamins E and D. According to Barry, the evidence shows that people who smoke or have been exposed to asbestos are more likely to develop lung cancer.

The task force made it clear that the new recommendations don't apply to people who are pregnant or deficient in vitamins and minerals. Barry says there is a separate recommendation on the use of supplements to prevent neural tube defects in the baby.

According to a commentary written by researchers at the University of Illinois, most people don't really need a supplement. Jenny said that vitamins and supplements are not a silver bullet for healthy Americans. We can see that vitamins can be harmful, even though most people think they are benign.

Barry says that taking supplements may make people feel less secure. They may forgo other, more effective, measures for preventing cancer and cardiovascular disease such as eating a healthy diet high in fruits and vegetables, exercising and following recommendations for cancer screenings.

The journal's title is "JAMA."