Thought you could never have too much of a good thing? Well actually, you can.
“We are not sure why this is happening at the molecular level but evidence shows that people who take more dietary supplements than needed tend to have a higher risk of developing cancer,” said Tim Byers, associate director for cancer prevention and control at the CU Cancer Center.
Research into vitamin consumption first began 20 years ago after scientists observed that those who ate more fruit and veg were less likely to have cancer.
Following this, researchers wanted to explore if taking even more vitamins and minerals could reduce the risk further.
“When we first tested dietary supplements in animal models we found that the results were promising,” said Byers.
“Eventually we were able to move on to the human populations. We studied thousands of patients for ten years who were taking dietary supplements and placebos.”
But the results were not what they expected.
“We found that the supplements were actually not beneficial for their health. In fact, some people actually got more cancer while on the vitamins,” explained Byers.
One trial found that taking more than the recommended dosage of beta carotene supplements could increase the risk of lung cancer and heart disease by 20%.
Another trial found that folic acid, which was thought to help reduce the number of polyps in a colon, actually increased the number.
“At the end of the day we have discovered that taking extra vitamins and minerals do more harm than good.
“This is not to say that people need to be afraid of taking vitamins and minerals,” added Byers. “If taken at the correct dosage, multivitamins can be good for you. But there is no substitute for good, nutritional food.”
He added that many adults take vitamin supplements, but don't necessarily need to.
Instead, he urged the public to get their daily dose of vitamins and minerals through a healthy diet.