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This story has been bobbing around for a couple of weeks, so it's probably time to rant about vitamins, just a little. A major report has concluded that antioxidant vitamin pills do not actually prevent you from dying and some might actually make you more likely to die.
The Cochrane Collaboration (which is a not-for-profit organisation which provides thorough reviews not only of medical things like but social interventions and has been going for about 20 years) pulled together data from as many sources as possible: they found 16,111 reports of studies on vitamins, which ultimately became just 67. This is entirely normal if you are assessing sources for relevance, but has become a real fascination for people who didn't like the results of this review.
Given that celebrity commands airtime and column inches we've had the opportunity to hear what everyone from Sir Cliff Richard to Carole Caplin who used to advise Cherie Blair thinks. Most have decried or tried to minimise the impact of this review.
The "Bad Science" column in the Guardian newspaper yesterday provided an excellent analysis which did most of the rational ranting that I wanted to do... http://www.guardian.co.uk/commentisfree/2008/apr/26/medicalr esearch.health .
It reports that of 16,111 reports...
- 12,703 were duplicates;
- 983 were studies of vitamins in children and so not relevant to a study of antioxidant vitamins in adults;
- of 750 studies of clinical trials on antioxidants but as the Cochrane Collaboration review was specifically comparing deaths on antioxidant pills versus deaths on placebo pills, 400 of these studies were excluded because there were no deaths.
Can it really be true? Scientists were quick to point out that the Cohrane Collaboration review had not condemned all vitamin tablets - taking a daily multivitamin tablet does not make you more likely to die. And the report was looking just at antioxidant vitamins: specifically vitamin E and betacatotene. Who takes high doses of these?
The Healh Food Manufacturers Associations spokesman said that "the analysis largely focused on extrordinarily and atypically high doeses of antioxidant vitamins [...] Supplement users would have some trouble trying to replicate this kind of daily intake".
But as the Bad Science column pointed out, the doses available as single vitamin supplements in Holland and Barratt (the main high street health food shop in the UK) are usually no more than 5mg less a day than the supplements investigated in the review.
While we in the UK are used to the idea of taking vitamin and other supplements, self-diagnosing combination for stronger hair and nails, for stress, St John's Wort for depression, whatever it might be, in other EU countries vitamins are classed as medicines.
Negotiations and comment on the EU Food Supplements Directive (agreed in 2002, challenged in the European courts but coming fully into force in 2009) showed this very clearly.
While there was support from medical groups such as the British Dietetic Association, who were concerned that concerned about patients admitted to hospital suffering liver failure and severe stomach problems after taking high doses of vitamins. They also said that in some cases the supplements are preventing people getting the correct treatment for other chronic illnesses.
On the other side, the Alliance for Natural Health, National Association of Health Food Stores and others complained that this was curtailing the rights of people to choose to have a healthier diet through supplements.
The UK press generally sided with the vitamin suppliers - anything to say that the EU was doing something that was bad for you-the-British-people-Britain-Britain-Britain-out-out-out-s ave-the-pound-stop-the-EU, while interestingly consumer association Which? backed the legislation.
A saying of my grandmother's keeps coming to mind: "everything in moderation".
Eating sensibly and exercising regularly are inevitably going to be a better way of getting and staying healthy than popping pills.
A lot of a good thing is not necessarily better for you than a little of it: it does not necessarily follow that if antioxidants are good for you high doeses are even better.
Celebrities might be famous for being experts in one field but it does not follow that they are experts worthy of quoting in any field.
One final thought: vitamin A is good for you. It helps your eyes adjust to light changes when you come in from outside and also helps keep your eyes, skin and mucous membranes moist. Also known as retinol, it is thought to work effectively as an anti-aging agent in skin creams. Polar bear liver is the richest source of vitamin A known on earth. But it's so rich in vitamin A eating it would kill you. I guess that's if you survived trying to get hold of a polar bear liver in the first place...
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Posted by rose22 on 2008-04-27 12:42:18 | Rating: | Views: 160
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