Science and Fiction

January 27th, 2007 by Ben Goldacre in bad science, nutritionists | 13 Comments »

New audience, this can’t last. From their New Years Diet and Detox Special.

Ben Goldacre
New Statesman
22nd January 2007

Eating your greens, just like your mother told you, is
very sensible. You don’t need a doctor, a diet guru, or a
journalist, to tell you; and that kind of broad brush
guidance is fairly well supported by research data. But
increasingly we are subjected to an entirely new category
of dietary advice: wilfully overcomplicated, frequently
brand-specific, and served up by a string of
dubious authority figures recommending fish oil for
kids, olive oil for wrinkles, the miracle of antioxidants
and pomegranates, and more.

None of this is driven by a genuine, balanced appraisal
of the relevant scientific research. Nutritionism
has become – and I use the phrase advisedly – the “bollocks
du jour”. So why don’t doctors, dietitians, and
genuine nutrition academics make the same elaborate
claims for the miracle powers of individual foods that
journalists, manufacturers and gurus do?

The reality is, nutritionism is driven by a set of first
year undergraduate errors in interpreting scientific
data. Gurus will classically extrapolate from theoretical
laboratory bench data, and pretend that this has
proven ramifications in the real world. One newspaper
nutritionist tells us that turmeric is “highly protective
against many forms of cancer, especially of the
prostate”. But there are, for turmeric and prostate cancer,
only speculative lab studies of cells, growing or not
growing, in glass dishes, under microscopes, and usually
from rats. This is not a sound scientific foundation
for real world advice on curry.

Similarly they will extrapolate from observational
data to give interventional advice. Angela Dowden, for
example, a “registered nutritionist” (she is proud to
tell us) writes in the Mirror that “an Australian study
in 2001 found that olive oil (in combination with fruit,
vegetables and pulses) offered measurable protection
against skin wrinkling.” But the paper she refers to
(Purba MB et al. J Am Coll Nutr. 2001 Feb; 20(1):71-80)
was an observational study, not an intervention study.
It did not give people olive oil for a time and then
measure differences in wrinkles. It pooled four different
groups of people to get a range of diverse lifestyles,
observed their diets and observed their skin: it found
that some people who already had completely different
eating habits also had different amounts of wrinkles,
which is hardly a surprise.

People with completely different lives will always
have different diets, and different wrinkles: that does
not mean the food directly affects the wrinkles. It
could be any number of other factors. I eat well and I
don’t have many wrinkles. I also have a middle-class
background, an indoor job, and a life free from strife.
There’s no more scientific mystery in interpreting
Dowden’s claims than that: you can decide for yourself
if her advice is justified by the study that she
quoted.

The intellectual crimes go on: cherry-picking data,
selecting only papers that support their claims, ignoring
the counterveiling evidence; many simply invent
“research” or talk about “studies” that don’t exist. Let’s
not forget, either, that “nutritionist” is an unprotected
title that anyone can use. The Daily Mail, meanwhile,
has a bizarre ongoing ontological project to divide all
the foodstuffs (indeed all the inanimate objects) in the
world into those that either cause, or cure, cancer.
But it would be a mistake to buy into a lazy moral
framework where the public are innocent victims,
misled by mendacious hacks and quacks. We are at
best willing victims: because it’s very seductive, politically
and psychologically, to think that food will be a
major determinant of health. It is, after all, a reassuringly
individualist project, that speaks to us of personal
responsibility.

In reality, of course, social
class is the primary determinant
of ill health: life expectancy
is 70 years in Kentish
Town, but two miles
away in Hampstead it’s 80
years. But nutritionists reassure
us that we can take control
of our fate; even that the
ignorant are responsible for
their own heart disease. “Dr” Gillian McKeith, with
her non-accredited, correspondence-course PhD
from the US, will frighten, humiliate and abuse the
obese for our entertainment on national television, to
reassert this message.

But there is a more interesting question: how did basic,
sensible dietary and lifestyle advice come to be presented
in such technical, overcomplicated and biomedical
terms? The blame lies, sadly, with the medical
profession. In the 1960s, epidemiologists discovered
genuine, hidden, lifestyle risk factors for death and
disease. Nobody expected smoking to cause lung cancer,
and even asbestos was an unlikely suspect for murder,
until careful statistical work revealed its dangers.

Emboldened by these successes, medical academics
tried to uncover more of these landmark lifestyle risk
factors. We failed. Diet seemed to be a runner, but beyond
the most basic sensible dietary advice, and despite
some promising early leads, the evidence simply
didn’t back up any of the more specific culprits.

Antioxidants are the textbook example, since they
are, after all, the cornerstone of all the most prevalent
claims of the nutritionism industry. Chemicals related
to antioxidants are elevated in blood tests in people
who live longer; and on paper, in a metabolism textbook,
looking at what they do in the body, you might
think antioxidants should be helpful; they’re also
abundant in vegetables, and eating your greens is one
of the few things shown to be good for you. Filling up
on antioxidants made sense as a hypothesis. But huge
numbers of studies, systematic reviews of those studies,
and meta-analyses of those studies, have shown
that antioxidant supplements have no benefit on heart
disease, and may even increase the risk of cancer.

That’s science and sometimes it is counter-intuitive.
But by the time these negative results were coming
in, following justifiable public health interventions on
smoking and HIV, the medical profession had entered
the arena of lifestyle advice. We rendered basic health
issues like exercise and diet in overly technical terms,
and suggested, implicitly and sometimes explicitly,
that diet was a complex biomedical issue. It was a
promise we couldn’t pay out on, and so the nutritionism
industry moved in to take our place. More than
that, these stories make excellent copy. Miracle cures
and genuine hidden killers represented a golden age of
medical headlines. The media has still not found a way
to cover the gentle progress and the shavings of probability
that characterise modern medical research.

There is no doubt that basic sensible dietary and
lifestyle advice is sound. You should exercise more, eat
more fibre, and more fresh fruit and vegetables. But as
soon as someone starts telling you that you need a
handful of brazil nuts every day to avoid being deficient
in selenium, you can be sure it’s more about their
professional aggrandisement, and building a market
for their new industry, than your health.

Dr Ben Goldacre writes the “Bad Science” column in
The Guardian


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13 Responses



  1. Paul Crowley said,

    January 28, 2007 at 12:26 am

    The Daily Mail’s project is the oncological ontology, then?

  2. Dave M said,

    January 28, 2007 at 1:02 am

    Great piece, although the most important thing I took from this was that I really have to move out of Kentish Town!

  3. JunkkMale said,

    January 28, 2007 at 7:43 am

    “There is no doubt that basic sensible dietary and lifestyle advice is sound. You should exercise more, eat more fibre, and more fresh fruit and vegetables.”

    Bang on. But it wouldn’t fill too many column inches, and would soon cease to be newsworthy in the repetition. Much better to keep finding something new, make it very complex, and preferably stir up a controversy that will only result eventually in the product being remembered enough to sustain the marketing.

    Works for all concerned, especially those with whole new careers being the media interface du jour for lazy other media seeking a quick way to fill some space or time as well.

    Shame it only reached the audience of the New Statesman who, I would hazard, have already suspected as much. Bet there’s still a few ‘out of sell-by date’ bottles of vits to counter ague and ill-humours lurking in the back of the cabinet, though.

  4. evidencebasedeating said,

    January 28, 2007 at 10:08 am

    Spot on with the observations. Of course, the whole concept of nutritionalism (food group exclusions + weird combo of supplements by the handful + manic media preachers) grew from the fact herbal medicines were deliberately excluded from the original UK Medicines Act. What at the time permitted bona fide medical herbalists to continue their practice in parallel with the fledgling NHS has mushroomed (Shiitake, obviously) to the bloated and over-hyped supplement market du jour.

    So whilst taking the one-a-day multivit and mineral (MVM) complex may afford you psychological if not actual health insurance, the fantastic claims about B COMPLEX!!!!, VITAMIN C!!!!, VITAMIN E!!!!! are falling apart as conventional, well conducted studies fail to demonstrate their over-hyped benefits for the well fed, western populations.

    In 2003, the Expert Committee on Vitamins and Minerals concluded that over 20 nutrients commonly consumed at beyond-nutritional need level had inadequate evidence to support a robust ‘safe upper limit’ level – instead, suggesting ‘guidance’ maximal intakes instead www.food.gov.uk/multimedia/pdfs/vitmin2003.pdf. So current consumers taken in by the ‘vitamin pill for every il’ hype are our ‘guinea pigs’ for future research…..

    Just when will the media take an ‘emperors new clothes’ approach to the increasingly bizarre rantings and recommendations of the meeja nutritionists exploiting column inches and broadcast time for self-aggrandisement and opportunities to push their endorsed wares?

    I h

  5. Chris said,

    January 28, 2007 at 2:40 pm

    Nice overview of the field of nutritionism.
    Sorry to be pedantic, but shouldn’t it be “countervailing” in paragraph six, line three?

  6. ellazimm said,

    January 28, 2007 at 5:29 pm

    I know this sounds trite but how do you stop from being made fun of by your friends at dinner parties? Last night I was “prompted” to have a rant about some similar topic and felt as if I was the hired entertainment. I’d love to have your job but more importantly I’d love to be taken seriously. Why is skepticism a side show?

  7. AitchJay said,

    January 28, 2007 at 10:25 pm

    I think it’s interesting and engaging to hear anyone speak passionately about a topic, whatever the situation. Apart from manic street preachers, that is..

    Get some new friends: ones that enjoy intellectual stimuli.

  8. Universal Antidote said,

    January 29, 2007 at 12:43 am

    I agree with ellazimm about feeling like a sideshow. What I hate is having to be all Debbie Downer around my friends who brag about how echinacea (yuck!) and Airborne cure their colds. When I try to explain regression to the mean or the placebo effect, let alone RCTs or systematic reviews, no matter how beautifully I translate the concepts into English, they look at me like I’m speaking Greek.

    If it were all harmless, that’s one thing, but isn’t echinacea supposed to be rather toxic in moderately high amounts?

  9. kim said,

    January 29, 2007 at 9:53 am

    There are so many people I’d love to show this to – all the ones who worry that they’re not getting enough zinc, or vitamin B12, or whatever. (The person I’d really like to see this is India Knight, who week after week in her Sunday Times column bangs on about nutrition despite the fact that in her own words, she “smokes like a chav”. Strewth.)

    There are twp things I’d take you up on. One is the correlation between social class and mortality rates. Of course middle-class people do less dangerous jobs, smoke less and live in better quality housing. But surely one of the reasons middle-class people live longer is because they eat better?

    The second is the idea that the correlation between smoking and lung cancer came as a surprise. I know Richard Doll always claimed this was the case but I read recently that the original government brief for his research asked him to look at whether smoking might be a cause of lung cancer. (But the fact that I read it somewhere doesn’t of course make it true…)

  10. Kells said,

    January 29, 2007 at 5:00 pm

    a. Good article Ben – just getting better and better.
    b. ellazimm and Universal Antidote – don’t give up, you will find a way of getting the message across if you keep at it. It’s hard not to rant but that generally won’t work (but is enjoyable). Just the odd comment or question that shows up the silliness of the ‘cure’ being discussed is enough I think, let the penny drop.
    I realised my friends took me seriously years ago when I refused the offer of eggs at breakfast. There was a wide eyed “Why? Whats wrong with eggs??” moment until I explained I just don’t like the taste.

  11. Dioscorides said,

    January 29, 2007 at 6:22 pm

    The human machine is incredibly complicated and interacts at multiple levels with its environment beginning from conception. Much of its interactive capability is genetic but each generation faces complexities far greater than previous generations. All studies that assume they can examine one human mechanism in isolation from this complex animal are beginning with a ridiculous assumption. The best they can do is have good study control amd excellent study design and competent and honest biostatisticians to analyze the data. Then they can make some likely valid observations. However the comments on study outcomes being self-serving to those doing and touting the studies is right on. I used to tell my patients that if 100 physicians were asked a question and all agreed then there was an 80% chance they were correct. If there were two well defended opinions then each only had a 50% chance of being correct and if three or more well defended opinions existed then it was just “take your chance”. So all of ‘Modern” medicine is 80%, 50% or take your chance.

  12. NelsonGabriel said,

    January 30, 2007 at 5:33 pm

    kim: Doll and colleagues were not the first to suggest that there was a smoking-lung cancer link, indeed there is a whole fascinating story about Nazi science here. There is a fascinating book by Robert Proctor “The Nazi War on Cancer”
    ISBN 069 107 0512

    The scientist who found the smoking-cancer link was called Mueller. It seems that his studies were excellent, and certainly the statistical treatment of it was state-of-the-art, though it would not meet modern standards. This is what I was told by Kevin McConway of the Open Uni. He had heard of Mueller but did not know about the book.

    The amazing thing is how modern the regime’s preoccupations were: they discouraged smoking and alcohol, encouraged vegetarianism and even had laws about pesticide residues and food additives. But of course at the heart of it was preserving a healthy race, staying fit to fight/produce babies.

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