Fri, May 25, 2007 page9

• What if the frugs don't work?

  More of us are taking food supplements to `balance' our diets, but they may be doing us more harm than good

  • By Lucy Atkins / THE GUARDIAN
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  They are exculpation, insurance and saintliness in handy pill form. They supposedly guard against anything from wrinkles to cancer. But are dietary supplements -- from the humble multivitamin to the mega-dose antioxidant -- really as benign as they seem?

  A study published recently in the Journal of the National Cancer Institute found that men with prostate cancer who took more than seven multivitamins a week were 30 percent more likely to get an advanced and fatal form of the disease.

  This comes after a large -- though hotly contested -- review published in the Journal of the American Medical Association in February found that people who took antioxidant vitamin tablets (particularly vitamins A and E and beta-carotene) were more likely to die earlier than those who did not.

  Such research seems to fly in the face of common sense. We all know vitamins are "good" for us. Indeed, thanks to a national obsession with TV diet "gurus," many people believe they are de facto deficient in key nutrients and can only be healthy if they supplement their food with pills or potions. Even those not downing spirulina algae with breakfast probably own at least one pack of multivitamins.

  Catherine Collins, chief dietician at St. George's Hospital, London, said: "The whole idea that you must meet some vitamin and mineral target every day of your life is a marketing myth: you can eat lots of fruit and veg one day and not much the next, but over a week you will still get the right amount of nutrients."

  "There is very little scientific evidence of any benefit whatsoever in taking a daily multivitamin, even in old people," she said.

  Indeed, taking daily vitamins could be positively harmful if you eat a poor or highly restricted diet, then assume you are nutritionally covered by popping a pill.

  "You cannot exist on a poor diet and then shore yourself up with a multivitamin," Collins said.

  Supplements, she said "have become pseudo-medicines," prescribed by trusted therapists and frequently taken where conventional medicine has failed.

  Many people, for instance, routinely pop supplements such as echinacea pills to ward off colds, or evening primrose oil to counter hot flushes or premenstrual tension, despite a complete lack of scientific evidence that these supplements actually work.

  "The supplements industry treats the body like a blunt, crude tool," Collins said. "You put in a certain vitamin and it solves a problem. But the body does not work like this at all. It has a far more complex and sophisticated mechanism for absorbing vitamins and minerals from food."

  Toni Steer, nutritionist with the UK's Medical Research Council's Human Nutrition Research in Cambridge, said supplements cannot compete with real food because when we eat fruits and vegetables the vitamins and nutrients interact with other chemicals to produce positive effects on the body.

  "If these same vitamins are pulled out and isolated in pill form, there is no guarantee at all that they will have the same effect," she said.

  There is also a trend for taking "mega-doses" of specific vitamins in order to target particular health issues. For instance, some women swallow hefty quantities of vitamin B6 to avoid premenstrual tension. Again, this could be misguided.

  "The idea that taking high quantities of vitamins will give you a health boost -- like putting premium petrol in your car -- is complete nonsense," Collins said.

  People assume that vitamins are harmless, even in high doses, because they are "natural."

  But swallowing a gram of vitamin C is the equivalent of consuming a whole bush of broccoli or four liters of orange juice: hardly a "natural" amount.

  "With vitamins and minerals, more is not necessarily good," Collins said.

  Some, such as vitamin C, will simply be excreted if taken in large doses. The body can use a maximum of 500mg of vitamin C a day.

  Others may be even more problematic. Most multivitamin pills, for instance, contain vitamin A. But if high doses of vitamin A -- above 3,000 micrograms -- are taken by pregnant women, they can cause birth defects. Since there is no upper limit on how much of any vitamin a product may contain, some vitamin tablets, said Collins, actually contain 30 percent to 40 percent more than the recommended daily allowance stated on the packet. This is why pregnant women are advised to take only pregnancy-specific multivitamins.

  Another recent trend is to take daily doses of antioxidants such as beta carotene, vitamin A and C or selenium in order to protect yourself against cancer, heart disease or signs of premature aging. Found naturally in fruit and vegetables, antioxidants protect the body against cell damage. Dietary studies show that people who have a high level of antioxidants in their diet have a lower risk of heart disease and certain cancers. This is why we are told to eat at least five portions of fruit and vegetables a day. However, studies also seem to suggest that taking antioxidants in pill form may not have the same effect and may even be harmful.

  "There's still conflicting evidence about whether taking certain vitamin supplements can affect a person's risk of cancer," said Alison Ross, science information officer at Cancer Research UK. "These products don't seem to give the same benefits as vitamins that naturally occur in our food."

  The British Heart Foundation is similarly cautious.

  "Research does not support the claim that taking extra antioxidants in the form of supplements will benefit the heart," its spokesperson said.
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