Vitamin pills can increase cancer risk by 20pc - expert
Taking vitamin supplements may actually increase the risk of getting cancer and heart disease, new research has warned.
A decade-long study that examined the healthy benefits of supplements on thousands of people found they can do "more harm than good".
Experts warned that taking above the recommended daily amount of over-the-counter vitamins may increase the risk of developing cancer and heart disease by up to 20pc.
And they urged the public to get their vitamins from a healthy diet rather than rely on pills.
"We are not sure why this is happening, but evidence shows that people who take more dietary supplements than needed tend to have a higher risk of developing cancer," said Dr Tim Byers of the University of Colorado Cancer Centre.
The revelations prompted Dr Byers to call for supplements to be reclassified as drugs rather than food in the US.
Depending on the contents, such supplements are either classed as medicines or food in the UK and are subject to different regulations.
Dr Byers said the study showed supplements were a "public health" issue and added that he wanted to see authorities "pay more attention to safety and how they are advertised".
The research team began investigating the potential health benefits contained within vitamins and minerals 20 years after observing that people who ate more fruits and vegetables tended to have less cancer.
Scientists wanted to see if taking supplements would produce the same effects.
But they were surprised to discover that far from boosting health, taking too much of a supplement can increase the risk of potentially fatal diseases.
"We found the supplements were not beneficial to health. In fact, some people actually got more cancer while on the vitamins," said Dr Byers.
"It comes down to dose and educating physicians and the general public to stay away from high-dose vitamins, only taking them in the recommended range".