Tim Byers, associate director for cancer prevention and control at the University of Colorado cancer centre, said that attempts by scientists to reduce cancer risk over the past three decades using vitamin pills were "kind of a sorry story".
Taking extra vitamins "does more harm than good" and increases the risk of cancer and heart disease, a major study has revealed. Around 18 million Brits down supplements thinking they are getting a health boost, but research has found they can have the opposite effect.
Dr Tim Byers - one of the world's top cancer experts - examined research papers spanning 30 years. He looked at three widely taken Âover-the-counter pills and supplements, vitamin E tablets, beta-carotene and folic acid, and warned against exceeding the recommended daily amount.
"Eventually we were able to move on to humans. We studied thousands of patients for 10 years who were taking dietary supplements and placebos. "We found that the supplements were actually not beneficial for their health. In fact, some people actually got more cancer while on the vitamins."
Folic acid supplements are thought to be taken by more than 230,000 pregnant UK women each year as it can help prevent spina bifida and other birth defects affecting the brain and spine. But one study examined by Dr Byers's team found too much increased the chances of getting cancer by 56 percent.
But the research found too much in supplement form in fact increased the number of dangerous polyps. Two trials of beta-carotene supplements found taking more than the recommended dose increased the risk of developing lung cancer and heart disease by 20%.
Meanwhile another trial of 35,000 people between 2001 and 2014 in the States found taking too many vitamin E tablets increased the risk of developing prostate cancer by 17%. Dr Byers, associate director for prevention and control at the University of Colorado Cancer Center, US, began his study after it emerged two decades ago that people eating more fruit and vegetables were less likely to get cancer.
"But there is no substitute for good food."
