Vitamin supplements can increase risk of cancer and heart disease

Researchers reviewing trials involving thousands of patients say taking extra vitamins and minerals does more harm than good

Dietary supplements, such as over-the-counter multivitamins, do "more harm than good" and can increase the risk of developing cancer and heart disease, according to research in the US.

The study by the University of Colorado, which reviewed several trials involving thousands of patients over a decade, showed that those who took extra vitamins and minerals were more likely to have health problems.