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Wed, Jul-18-07, 07:43
Vitamin C useless in combatting colds
By Rebecca Smith, Medical Editor
Last Updated: 9:06am BST 18/07/2007
Have your say: Do vitamin pills do any good?
Taking vitamin C supplements to prevent a cold is a waste of time and money, say researchers. A review of 30 studies involving more than 11,000 people found that taking the tablets had no effect on the average person.
Researchers found the benefit of taking vitamin C supplements to be slight when it comes to catching colds
But it could be a good idea for those under extreme physical stress such as marathon runners, soldiers on exercise and skiers.
Thousands of people take the supplements and some take large doses in the belief it helps them stay healthy but the analysis shows it is unnecessary. The work was carried out by the Cochrane Collaboration, a not-for-profit organisation dedicated to disseminating research on health care.
Vitamin C, also known as ascorbic acid, is a water soluble substance, meaning the body cannot store it so it must be taken daily as part of a balanced diet.
Adults need around 60mg a day and smokers and pregnant women can take slightly more but some people take up to 1,000mg a day. A 230ml glass of orange juice provides about 97mg.
advertisementFor most people, the benefit of taking vitamin C supplements is so slight when it comes to colds that it is not worth the effort or expense, the authors say. "It doesn't make sense to take vitamin C 365 days a year to lessen the chance of catching a cold," said the co-author Harri Hemilä, a professor in the Department of Public Health at the University of Helsinki.
Prof Peter Openshaw, from Imperial College London, said a normal healthy diet provided enough vitamin C to prevent deficiency. He said: "There is no evidence that taking huge doses of vitamin C does you any harm but it costs quite a lot of money and it would be better if people spent their money on getting fresh food rather than making up for a bad diet by taking vitamins."
But the researchers found that people under physical stress who took the recommended daily amount of vitamin C were 50 per cent less likely to have colds.
John Oxford, a cold and flu expert and Professor of Virology at Barts and The London, Queen Mary's School of Medicine and Dentistry, said the analysis did not solve the debate because it showed some effect in some people.
He said: "If vitamin C has some effect in particular groups than you have to ask why and what is that effect. It would have been clearer if the analysis had shown no effect at all." He suggested that normal people took in enough vitamin C in their diets so tablet supplements were unnecessary.
Those under physical stress could find supplements useful because they could use up their dietary intake of vitamin C more quickly.
But Prof Oxford said he was "sceptical" about the conclusions of the study and added that the importance of vitamin C for health was "beyond doubt".
In the 1970s, the Nobel Prize-winning chemist Linus Pauling wrote a book, Vitamin C and the Common Cold, encouraging people to take 1,000mg of the vitamin daily.
Despite studies showing this had no benefit, Pauling never altered his view and several other experts have taken up the cause.
Researchers continue to examine vitamin C alone and in combination with other vitamins and substances, such as echinacea, to examine if it is of any use in preventing and treating diseases and conditions, including cancer.
http://www.telegraph.co.uk/news/main.jhtml;jsessionid=ZQXCSLMRGTJ3PQFIQMFSFF4AVCBQ0IV0?xml=/news/2007/07/18/nvit118.xml
By Rebecca Smith, Medical Editor
Last Updated: 9:06am BST 18/07/2007
Have your say: Do vitamin pills do any good?
Taking vitamin C supplements to prevent a cold is a waste of time and money, say researchers. A review of 30 studies involving more than 11,000 people found that taking the tablets had no effect on the average person.
Researchers found the benefit of taking vitamin C supplements to be slight when it comes to catching colds
But it could be a good idea for those under extreme physical stress such as marathon runners, soldiers on exercise and skiers.
Thousands of people take the supplements and some take large doses in the belief it helps them stay healthy but the analysis shows it is unnecessary. The work was carried out by the Cochrane Collaboration, a not-for-profit organisation dedicated to disseminating research on health care.
Vitamin C, also known as ascorbic acid, is a water soluble substance, meaning the body cannot store it so it must be taken daily as part of a balanced diet.
Adults need around 60mg a day and smokers and pregnant women can take slightly more but some people take up to 1,000mg a day. A 230ml glass of orange juice provides about 97mg.
advertisementFor most people, the benefit of taking vitamin C supplements is so slight when it comes to colds that it is not worth the effort or expense, the authors say. "It doesn't make sense to take vitamin C 365 days a year to lessen the chance of catching a cold," said the co-author Harri Hemilä, a professor in the Department of Public Health at the University of Helsinki.
Prof Peter Openshaw, from Imperial College London, said a normal healthy diet provided enough vitamin C to prevent deficiency. He said: "There is no evidence that taking huge doses of vitamin C does you any harm but it costs quite a lot of money and it would be better if people spent their money on getting fresh food rather than making up for a bad diet by taking vitamins."
But the researchers found that people under physical stress who took the recommended daily amount of vitamin C were 50 per cent less likely to have colds.
John Oxford, a cold and flu expert and Professor of Virology at Barts and The London, Queen Mary's School of Medicine and Dentistry, said the analysis did not solve the debate because it showed some effect in some people.
He said: "If vitamin C has some effect in particular groups than you have to ask why and what is that effect. It would have been clearer if the analysis had shown no effect at all." He suggested that normal people took in enough vitamin C in their diets so tablet supplements were unnecessary.
Those under physical stress could find supplements useful because they could use up their dietary intake of vitamin C more quickly.
But Prof Oxford said he was "sceptical" about the conclusions of the study and added that the importance of vitamin C for health was "beyond doubt".
In the 1970s, the Nobel Prize-winning chemist Linus Pauling wrote a book, Vitamin C and the Common Cold, encouraging people to take 1,000mg of the vitamin daily.
Despite studies showing this had no benefit, Pauling never altered his view and several other experts have taken up the cause.
Researchers continue to examine vitamin C alone and in combination with other vitamins and substances, such as echinacea, to examine if it is of any use in preventing and treating diseases and conditions, including cancer.
http://www.telegraph.co.uk/news/main.jhtml;jsessionid=ZQXCSLMRGTJ3PQFIQMFSFF4AVCBQ0IV0?xml=/news/2007/07/18/nvit118.xml