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Vitamins May Boost Cancer And Heart Disease Risk

Vitamins May Boost Cancer And Heart Disease Risk

Experts have warned that taking more than the recommended daily dose of over-the-counter vitamins could increase the risk of developing cancer and heart disease by up to 20%.

A 10-year study into the effect of vitamin supplements on thousands of people found they can do "more harm than good".

The study was led by the University of Colorado Cancer Centre and raises questions about the market for shop-bought vitamins, which was worth an estimated £385m in 2012.

The researchers have urged the public to get their vitamins from a healthy diet rather than pills.

Professor Tim Byers said: "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."

The team began to investigate the potential health benefits of vitamins and minerals after observing that people who eat more fruit and vegetables tend to have lower cancer rates.

The researchers wanted to see if taking vitamin supplements would produce the same results.

"When we first tested dietary supplements in animal models we found that the results were promising," Prof Byers said.

"Eventually we were able to move on to the human populations. We studied thousands of patients for 10 years who were taking dietary supplements and placebos."

The study found that rather than boosting people's health, taking too much of a vitamin supplement can increase the risk of fatal diseases.

During one trial, the researchers looked into the effects of beta-keratin supplements.

The results found that taking more than the recommended dosage increased the risk of lung cancer and heart disease by 20%.

"We found that the supplements were actually not beneficial for their health. In fact, some people actually got more cancer while on the vitamins," Prof Byers said.

He stressed that the findings did not suggest that all vitamin supplements are dangerous, although taking too many of them may pose a health risk.

"This is not to say that people need to be afraid of taking vitamins and minerals," he said.

"If taken at the correct dosage, multivitamins can be good for you. But there is no substitute for good, nutritional food.

"At the end of the day we have discovered that taking extra vitamins and minerals do more harm than good."

The findings of the study were presented at the annual meeting of the American Association for Cancer Research.