Post by theshee on Mar 29, 2010 6:26:53 GMT 10
Vitamin and mineral supplements are widely touted by the multi-billion pound health food trade as the panacea for a long and active life. Vitamin C is presumed to fight off colds, betacarotene is touted as a cancer-beating drug, and vitamin E is supposed to defeat ageing and reduce the risk of a heart attack.
Alarming new evidence, however, suggests that rather than helping us fight off disease, certain supplements may actually increase the risks of cancer and a range of debilitating diseases.
The idea that vitamin supplements are healthy comes from the discovery that eating plenty of foods rich in the antioxidant vitamins A, C and E dramatically lowers the risk of cancer, heart disease and stroke. Scientists had assumed that fortifying the diet with antioxidant containing vitamin pills would have the same positive impact. But when the scientists looked a little closer, they found the opposite to be the case. By the time the scientists had discovered their error, the genie was out of the bottle and huge numbers of people had started taking mega-doses of vitamins and minerals.
“As with all things, too much of a good thing can be bad for you,” says Dr Derek Shrimpton, a consultant nutritionist to the Ministry of Agriculture and the food industry.
“Water is essential to life but if you drink seven litres of water in half an hour then the result is likely to be fatal.”
Professor Joseph Lunec, Director of Chemical Pathology at Leicester University, is also concerned about the possible dangers of taking large quantities of highly purified vitamin supplements. He warns: “Taking vitamin supplements in high doses may shunt the body’s biochemistry off in the wrong direction. The truth is we don’t know if this is what happens. That’s why we’re conducting our research.”
Scientists are especially worried about people taking high doses of the antioxidant beta-carotene, which the body converts into vitamin A. One study conducted by the US National Cancer Institute found that smokers taking 20 milligrams of beta-carotene increased their cancer risk by 16 per cent. Another study found that taking high levels of beta-carotene increased the cancer risk in smokers by 28 per cent. The US National Academy of Sciences is so concerned about the possible adverse effects of betacarotene that they refused to set a safe upper limit for daily consumption. Supplements containing “risky” levels of beta-carotene are freely available over the counter. The good news is that typical multi-vitamin pills contain only about one fortieth of the risky levels so even smokers can improve their health with a general supplement.
Professor Katherine Rice-Evans, Director of the International Antioxidant Research Centre at London’s Guy’s Hospital, says that people should be aware of the research but not alarmed. She says: “Smokers should not take more than about six milligrams of beta-carotene per day. Non-smokers should take about 6-10 milligrams per day.”
Vitamin A, closely related to beta-carotene, can also be highly dangerous if taken in excess. Pregnant women are especially vulnerable because vitamin A toxicity can cause birth defects and liver damage. Experts recommend that people limit their consumption to a maximum of about 3,000 micrograms a day - about four times the recommended daily allowance or RDA.
Even vitamin C may have a darker side. It has been known for many years that the vitamin can make certain forms of arthritis worse. The National Academy of Sciences recommends that you should not exceed 2,000 milligrams per day. And recent work published in the highly respected science journal, Nature, showed that as little as 500 milligrams per day produces DNA damaging and cancer inducing free radicals. Half a gram of vitamin C is only about eight times the RDA.
Professor Lunec, who conducted the vitamin C research, says that although his studies proved that the nutrient damages DNA it could, in the long run, end up protecting the body.
“It could be a bit like a vaccination. The vitamin C appears to damage certain genes. This primes the body’s repair mechanisms and encourages it to heal itself. High levels of vitamin C in the short term are damaging but in the long term it’s protective.”
Professor Lunec is now trying to discover the optimum vitamin C intake. He estimates that it is likely to be between 200 and 500 milligrams per day which is about 3 to 5 times the RDA.
www.newsmonster.co.uk/health/are-vitamin-supplements-killing-us.html
Alarming new evidence, however, suggests that rather than helping us fight off disease, certain supplements may actually increase the risks of cancer and a range of debilitating diseases.
The idea that vitamin supplements are healthy comes from the discovery that eating plenty of foods rich in the antioxidant vitamins A, C and E dramatically lowers the risk of cancer, heart disease and stroke. Scientists had assumed that fortifying the diet with antioxidant containing vitamin pills would have the same positive impact. But when the scientists looked a little closer, they found the opposite to be the case. By the time the scientists had discovered their error, the genie was out of the bottle and huge numbers of people had started taking mega-doses of vitamins and minerals.
“As with all things, too much of a good thing can be bad for you,” says Dr Derek Shrimpton, a consultant nutritionist to the Ministry of Agriculture and the food industry.
“Water is essential to life but if you drink seven litres of water in half an hour then the result is likely to be fatal.”
Professor Joseph Lunec, Director of Chemical Pathology at Leicester University, is also concerned about the possible dangers of taking large quantities of highly purified vitamin supplements. He warns: “Taking vitamin supplements in high doses may shunt the body’s biochemistry off in the wrong direction. The truth is we don’t know if this is what happens. That’s why we’re conducting our research.”
Scientists are especially worried about people taking high doses of the antioxidant beta-carotene, which the body converts into vitamin A. One study conducted by the US National Cancer Institute found that smokers taking 20 milligrams of beta-carotene increased their cancer risk by 16 per cent. Another study found that taking high levels of beta-carotene increased the cancer risk in smokers by 28 per cent. The US National Academy of Sciences is so concerned about the possible adverse effects of betacarotene that they refused to set a safe upper limit for daily consumption. Supplements containing “risky” levels of beta-carotene are freely available over the counter. The good news is that typical multi-vitamin pills contain only about one fortieth of the risky levels so even smokers can improve their health with a general supplement.
Professor Katherine Rice-Evans, Director of the International Antioxidant Research Centre at London’s Guy’s Hospital, says that people should be aware of the research but not alarmed. She says: “Smokers should not take more than about six milligrams of beta-carotene per day. Non-smokers should take about 6-10 milligrams per day.”
Vitamin A, closely related to beta-carotene, can also be highly dangerous if taken in excess. Pregnant women are especially vulnerable because vitamin A toxicity can cause birth defects and liver damage. Experts recommend that people limit their consumption to a maximum of about 3,000 micrograms a day - about four times the recommended daily allowance or RDA.
Even vitamin C may have a darker side. It has been known for many years that the vitamin can make certain forms of arthritis worse. The National Academy of Sciences recommends that you should not exceed 2,000 milligrams per day. And recent work published in the highly respected science journal, Nature, showed that as little as 500 milligrams per day produces DNA damaging and cancer inducing free radicals. Half a gram of vitamin C is only about eight times the RDA.
Professor Lunec, who conducted the vitamin C research, says that although his studies proved that the nutrient damages DNA it could, in the long run, end up protecting the body.
“It could be a bit like a vaccination. The vitamin C appears to damage certain genes. This primes the body’s repair mechanisms and encourages it to heal itself. High levels of vitamin C in the short term are damaging but in the long term it’s protective.”
Professor Lunec is now trying to discover the optimum vitamin C intake. He estimates that it is likely to be between 200 and 500 milligrams per day which is about 3 to 5 times the RDA.
www.newsmonster.co.uk/health/are-vitamin-supplements-killing-us.html