Vitamin health warning: Too many supplements can 'boost' risk of cancer and heart disease
TOO many vitamin pills can increase the risk of cancer and heart disease, say scientists.
Millions take over the- counter diet supplements to help prevent a host of diseases.
But a 10-year study has revealed that some cause serious harm in high doses.
Experts now believe the supplements are unnecessary for most people, who would be better off eating a nutritious meal.
It could pose a threat to an industry worth £500million a year in the UK.
Dr Tim Byers, of the University of Colorado Cancer Centre, led research involving thousands of people.
He said: “The evidence shows people who take more dietary supplements than needed tend to have a higher risk of developing cancer.
“We are not sure why this is happening.”
Beta-carotene, a Vitamin A precursor, was found to raise the risk of lung cancer and heart disease by 20 per cent when taken at above the recommended dose.
Vitamin B9, or folic acid, was thought to help reduce colon polyps, which can lead to bowel cancer.
But in a trial it actually increased the number of polyps.
Dr Byers said: “We studied patients who were taking dietary supplements and placebos.
The evidence shows people who take more dietary supplements than needed tend to have a higher risk of developing cancer.
The supplements were actually not beneficial for their health.
In fact, some people got more cancer while on the vitamins.”
Most people get the recommended daily doses of vitamins and minerals from a proper diet but more than half of Britons take supplements.
Recent research showed 63 per cent have taken pills in the past year, with 45 per cent of women and 55 per cent of over-65s using them daily.
Millions pop iron tablets to boost red blood cell production, calcium is taken for strong bones and teeth and Vitamin C to keep cells healthy.
But few taking their daily supplements realise how high the doses can be and how they can do damage.
A one gram Vitamin C pill is equivalent to four litres of orange juice. Multivitamins – supplements containing a range of substances such as omega-3, iron, calcium and zinc – are among the most popular products on the market.
They are meant to bridge “nutritional gaps” and millions of people see them as a cure-all or a way of boosting resistance and energy.
Cancer specialist Dr Byers said: “If taken at the correct dosage, multivitamins can be good for you.
“But there is no substitute for good, nutritional food. And we have discovered that taking extra vitamins and minerals does more harm than good.”
Other experts agreed with his findings. Catherine Collins, of the British Dietetic Association, said: “We see patients taking extremely high doses of vitamins and minerals, which can cause harm.
People see it as affirmative action, a nutritional insurance. “But they are not benign and should be treated with respect.”
Family GP Dr Ian Campbell said: “Most people taking vitamin and mineral supplements are doing so unnecessarily.
“A healthy diet is all the vast majority of us need to maintain good nutritional health.
“There is little need for vitamin or mineral supplements in the absence of proven deficiencies.”
Diet specialist Zoe Harcombe said: “If you need a supplement, there’s something wrong with your diet.”
She pointed out: “We haven’t had supplements for most of the time humans have been around.”
Dr Emma Derbyshire, adviser to the Health Supplements Information Service, said of the study: “Vitamins and minerals are not intended to be used like drugs.
They are principally for making up shortfalls in intake and helping to maintain overall health.
“Taken in recommended amounts, vitamins and minerals are safe.”
The new findings were presented to the American Association for Cancer Research.
