The Rise of the Lifestyle Nutritionists – B – the answers
Everybody wants to be healthy, but how do you know who to trust 1? Obesity is rising; cholera and TB might not 2 kill you these days, but cancer or heart trouble probably will 3. These are biblical themes – death and disease – and we all want reassuring certainty 4 about what we can do to avoid them.
In the previous programme the presenter looked at the history of diet fads 5 and the magic pills 6 and potions 7 of the travelling medicine shows. They operated in a vacuum when nothing was known about 8 the science of food and health. This programme aims to look at the quality 9 of the evidence we do now have on diet and health. They will be considering the difficulties in collecting and interpreting it and also at the people who stretch and manipulate 10 that evidence for their own goals.
Academics, doctors and the government generally push 11 a rather simple line 12 on risk-factors for ill-health – get more exercise 13, drink in moderation, don’t smoke, eat more fresh fruit and veg 14 – all excellent advice. But what about the detailed, complicated advice 15 you get from nutritional therapists and in the media?
Susan Jebb is the head of the Medical Research 16 Council’s Human Nutrition Research Unit in Cambridge. She says there is very little evidence on which to base 17 absolutely detailed prescriptive advice to individuals about the exact amounts of certain foods or nutrients they should consume for optimal 18 health. They simply do not have that evidence to be so detailed.
Dr Jebb considers that the real danger in going down the route 19 of this very prescriptive individual advice is that it can make healthy eating seem like an extreme sport which becomes so difficult 20, so unachievable 21, so unobtainable 22 that people actually turn off 23 from the whole message. People think that if they can’t do it all there’s no point in trying to doing anything. This misses the established 24 evidence that even quite small changes can add up 25 to significant health benefits. Less than a century ago we were still discovering vitamins and minerals. The complexities of doing research in nutrition mean the evidence isn’t as strong as we’d like it to be, and it’s very rarely definitive.
Studies are rarely black-and-white, and as soon as you start to have grey areas 26 it leaves the evidence open to 27 interpretation. Then it becomes subjective, so you don’t know whose opinion or interpretation to believe. This lack of certainty breeds division 28 and controversy29.
Dr Goldacre says it’s all very well hearing one person’s opinion about evidence but what is it based on? How do you interpret a study? What do you do when the evidence is contradictory 30? We’re used to thinking about balance in terms of politics, prejudice 31 or opinion, but how can you be sure your interpretation is balanced 32 in terms of the evidence?
Professor Sir Ian Chalmers produces systematic reviews of academic literature on health33. He begins by saying you can pick and choose 34 among studies to prove almost whatever you want to prove 35. Worse than that – researchers can actually cherry-pick the results they want to submit for publication 36, so if they don’t like certain results they are less likely to submit them. To do the best work you make a thorough search for all relevant materials – this is called a systematic review 37. You look for material from unexpected sources, for instance in other languages, and you select the studies you think are most likely to be reliable 38 in terms of generating the data.These are studies which seem to be the fairest tests, where people have taken careful steps 39 to avoid the biases 40 which might otherwise mislead us.
Having chosen studies that fit these criteria 41 they look at their results and to overcome the element of chance involved, (because all tests have some uncertainty in them), they take results from the individual studies to create a total picture – this is called a metanalysis (or meta-analysis). The two scientists then give two examples of mistakes made, one in the field of food supplements and one in the field of paediatrics. Ben Goldacre mentions that for some time it was thought that anti-oxidant pills were valuable in preventing 42 cancer or heart disease and that they lengthened life. A recent systematic review and metanalysis / meta-analysis looked at all the trials on anti-oxidants and found that overall they seemed to be of no benefit 43 – and might even be harmful.
Professor Chalmers mentions a mistake made by Dr Spock, in his best-selling book called Baby And Childcare in which he recommended that the best thing to do was to make babies sleep on their tummies (=stomachs) from as early as possible. His advice, given with the best of intentions 44 and on the basis of a theory he had has resulted in more than 10,000 deaths in this country alone 45 – so-called cot deaths. This reminds us that scientists and medics can get things badly wrong 46 so we need to be far more careful 47, particularly when trying to change the behaviour of a whole population, Scientists have to make sure that their prescriptions and proscriptions, what people should and should not do is based on solid evidence 48.
It is fascinating and frightening to think that we can be misled 49 by our hopes beliefs and desire to do good. We can also be misled by people, companies and the media into thinking 50 there is good evidence when actually there isn’t.
* founder and former Director of the Cochrane Centre
Notes
phenomenon – noun – plural phenomena – a fact or situation which is observed to exist or happen 2) a remarkable person or thing
What about…? used 1) when asking for information or an opinion on sth:
eg What about the article in the paper? i.e. What do you think about the article in the newspaper?
2) also as a suggestion eg "What about you, Derek?" = "What do you think, Derek?" or "Could you be the person who does what we are talking about?"
3) It is sometimes used to move on from a subject, perhaps to one which has not been considered yet, or been overlooked or neglected.
Eg We’ve talked about John, and Mary – but what about me? (i.e. we have not considered my situation / fate….)
NB The noun advice – is pronounced differently from the verb advise
chilling – horrifying or frightening
to chill out is informal for to relax
bias – noun – plural biases – inclination or prejudice for or against one thing or person