That"s not the only time a placebo benefit has been found at the more dramatic end of the medical spectrum. A Swedish study in the late 1990s showed that patients who had pacemakers installed, but not switched on, did better than they were doing before (although they didn"t do as well as people with working pacemakers inside them, to be clear). Even more recently, one study of a very hi-tech "angioplasty" treatment, involving a large and sciencey-looking laser catheter, showed that sham treatment was almost as effective as the full procedure. showed that patients who had pacemakers installed, but not switched on, did better than they were doing before (although they didn"t do as well as people with working pacemakers inside them, to be clear). Even more recently, one study of a very hi-tech "angioplasty" treatment, involving a large and sciencey-looking laser catheter, showed that sham treatment was almost as effective as the full procedure.
"Electrical machines have great appeal to patients," wrote Dr Alan Johnson in the Lancet Lancet in 1994 about this trial, "and recently anything to do with the word LASER attached to it has caught the imagination." He"s not wrong. I went to visit Lilias Curtin once (she"s Cherie Booth"s alternative therapist), and she did Gem Therapy on me, with a big shiny science machine that shone different-coloured beams of light onto my chest. It"s hard not to see the appeal of things like Gem Therapy in the context of the laser catheter experiment. In fact, the way the evidence is stacking up, it"s hard not to see all the claims of alternative therapists, for all their wild, wonderful, authoritative and empathic interventions, in the context of this chapter. in 1994 about this trial, "and recently anything to do with the word LASER attached to it has caught the imagination." He"s not wrong. I went to visit Lilias Curtin once (she"s Cherie Booth"s alternative therapist), and she did Gem Therapy on me, with a big shiny science machine that shone different-coloured beams of light onto my chest. It"s hard not to see the appeal of things like Gem Therapy in the context of the laser catheter experiment. In fact, the way the evidence is stacking up, it"s hard not to see all the claims of alternative therapists, for all their wild, wonderful, authoritative and empathic interventions, in the context of this chapter.
In fact, even the lifestyle gurus get a look in, in the form of an elegant study which examined the effect of simply being told that you are doing something healthy. Eighty-four female room attendants working in various hotels were divided into two groups: one group was told that cleaning hotel rooms is "good exercise" and "satisfies the Surgeon General"s recommendations for an active lifestyle", along with elaborate explanations of how and why; the "control" group did not receive this cheering information, and just carried on cleaning hotel rooms. Four weeks later, the "informed" group perceived themselves to be getting significantly more exercise than before, and showed a significant decrease in weight, body fat, waist-to-hip ratio and body ma.s.s index, but amazingly, both groups were still reporting the same amount of activity.*
- I agree: this is a bizarre and outrageous experimental rinding, and if you have a good explanation for how it might have come about, the world would like to hear from you. Follow the reference, read the full paper online and start a blog, or write a letter to the journal that published it. - I agree: this is a bizarre and outrageous experimental rinding, and if you have a good explanation for how it might have come about, the world would like to hear from you. Follow the reference, read the full paper online and start a blog, or write a letter to the journal that published it.
What the doctor says.
If you can believe fervently in your treatment, even though controlled tests show that it is quite useless, then your results are much better, your patients are much better, and your income is much better too. I believe this accounts for the remarkable success of some of the less gifted, but more credulous members of our profession, and also for the violent dislike of statistics and controlled tests which fashionable and successful doctors are accustomed to display. If you can believe fervently in your treatment, even though controlled tests show that it is quite useless, then your results are much better, your patients are much better, and your income is much better too. I believe this accounts for the remarkable success of some of the less gifted, but more credulous members of our profession, and also for the violent dislike of statistics and controlled tests which fashionable and successful doctors are accustomed to display. Richard Asher Richard Asher, Talking Sense, Pitman Medical, London, 1972 Pitman Medical, London, 1972 As you will now be realising, in the study of expectation and belief, we can move away from pills and devices entirely. It turns out, for example, that what the doctor says, and what the doctor believes, both have an effect on healing. If that sounds obvious, I should say they have an effect which has been measured, elegantly, in carefully designed trials.
Gryll and Katahn [1978] gave patients a sugar pill before a dental injection, but the doctors who were handing out the pill gave it in one of two different ways: either with an outrageous oversell ("This is a recently developed pill that"s been shown to be very effective...effective almost immediately..."); or downplayed, with an undersell ("This is a recently developed pill...personally I"ve not found it to be very effective..."). The pills which were handed out with the positive message were a.s.sociated with less fear, less anxiety and less pain.
Even if he says nothing, what the doctor knows can affect treatment outcomes: the information leaks out, in mannerisms, affect, eyebrows and nervous smiles, as Gracely [1985] demonstrated with a truly ingenious experiment, although understanding it requires a tiny bit of concentration.
He took patients having their wisdom teeth removed, and split them randomly into three treatment groups: they would have either salt water (a placebo that does "nothing", at least not physiologically), or fentanyl (an excellent opiate painkiller, with a black-market retail value to prove it), or naloxone (an opiate receptor blocker that would actually increase the pain).
In all cases the doctors were blinded to which of the three treatments they were giving to each patient: but Gracely was really really studying the effect of his doctors" beliefs, so the groups were further divided in half again. In the first group, the doctors giving the treatment were told, truthfully, that they could be administering either placebo, or naloxone, or the pain-relieving fentanyl: this group of doctors knew there was a chance that they were giving something that would reduce pain. studying the effect of his doctors" beliefs, so the groups were further divided in half again. In the first group, the doctors giving the treatment were told, truthfully, that they could be administering either placebo, or naloxone, or the pain-relieving fentanyl: this group of doctors knew there was a chance that they were giving something that would reduce pain.
In the second group, the doctors were lied to: they were told they were giving either placebo or naloxone, two things that could only do nothing, or actively make the pain worse. But in fact, without the doctors" knowledge, some of their patients were actually getting the pain-relieving fentanyl. As you would expect by now, just through manipulating what the doctors believed doctors believed about the injection they were giving, even though they were forbidden from vocalising their beliefs to the patients, there was a difference in outcome between the two groups: the first group experienced significantly less pain. This difference had nothing to do with what actual medicine was being given, or even with what information the patients knew: it was entirely down to what the doctors knew. Perhaps they winced when they gave the injection. I think you might have. about the injection they were giving, even though they were forbidden from vocalising their beliefs to the patients, there was a difference in outcome between the two groups: the first group experienced significantly less pain. This difference had nothing to do with what actual medicine was being given, or even with what information the patients knew: it was entirely down to what the doctors knew. Perhaps they winced when they gave the injection. I think you might have.
"Placebo explanations".
Even if they do nothing, doctors, by their manner alone, can rea.s.sure. And even rea.s.surance can in some senses be broken down into informative const.i.tuent parts. In 1987, Thomas showed that simply giving a diagnosis-even a fake "placebo" diagnosis-improved patient outcomes. Two hundred patients with abnormal symptoms, but no signs of any concrete medical diagnosis, were divided randomly into two groups. The patients in one group were told, "I cannot be certain of what the matter is with you," and two weeks later only 39 per cent were better; the other group were given a firm diagnosis, with no messing about, and confidently told they would be better within a few days. Sixty-four per cent of that group got better in two weeks.
This raises the spectre of something way beyond the placebo effect, and cuts even further into the work of alternative therapists: because we should remember that alternative therapists don"t just give placebo treatments, they also give what we might call "placebo explanations" or "placebo diagnoses": ungrounded, unevidenced, often fantastical a.s.sertions about the nature of the patient"s disease, involving magical properties, or energy, or supposed vitamin deficiencies, or "imbalances", which the therapist claims uniquely to understand.
And here, it seems that this "placebo" explanation-even if grounded in sheer fantasy-can be beneficial to a patient, although interestingly, perhaps not without collateral damage, and it must be done delicately: a.s.sertively and authoritatively giving someone access to the sick role can also reinforce destructive illness beliefs and behaviours, unnecessarily medicalise symptoms like aching muscles (which for many people are everyday occurrences), and militate against people getting on with life and getting better. It"s a very tricky area.
I could go on. In fact there has been a huge amount of research into the value of a good therapeutic relationship, and the general finding is that doctors who adopt a warm, friendly and rea.s.suring manner are more effective than those who keep consultations formal and do not offer rea.s.surance. In the real world, there are structural cultural changes which make it harder and harder for a medical doctor to maximise the therapeutic benefit of a consultation. Firstly, there is the pressure on time: a GP can"t do much in a six-minute appointment.
But more than these practical restrictions, there have also been structural changes in the ethicil presumptions made by the medical profession, which make rea.s.surance an increasingly outre business. A modern medic would struggle to find a form of words that would permit her to hand out a placebo, for example, and this is because of the difficulty in resolving two very different ethical principles: one is our obligation to heal our patients as effectively as we can; the other is our obligation not to tell them lies. In many cases the prohibition on rea.s.surance and smoothing over worrying facts has been formalised, as the doctor and philosopher Raymond Tallis recently wrote, beyond what might be considered proportionate: "The drive to keep patients fully informed has led to exponential increases in the formal requirements for consent that only serve to confuse and frighten patients while delaying their access to needed medical attention."
I don"t want to suggest for one moment that historically this was the wrong call. Surveys show that patients want their doctors to tell them the truth about diagnoses and treatments (although you have to take this kind of data with a pinch of salt, because surveys also say that doctors are the most trusted of all public figures, and journalists are tlie least trusted, but that doesn"t seem to be the lesson from the media"s MMR hoax).
What is odd, perhaps, is how the primacy of patient autonomy and informed consent over efficacy-which is what we"re talking about here-was presumed, but not actively discussed within the medical profession. Although the authoritative and paternalistic rea.s.surance of the Victorian doctor who "blinds with science" is a thing of the past in medicine, the success of the alternative therapy movement-whose pract.i.tioners mislead, mystify and blind their patients with sciencey-sounding "authoritative" explanations, like the most patronising Victorian doctor imaginable-suggests that there may still be a market for that kind of approach.
About a hundred years ago, these ethical issues were carefully doc.u.mented by a thoughtful native Canadian Indian called Quesalid. Quesalid was a sceptic: he thought shamanism was bunk, that it only worked through belief, and he went undercover to investigate this idea. He found a shaman who was willing to take him on, and learned all the tricks of the trade, including the cla.s.sic performance piece where the healer hides a tuft of down in the corner of his mouth, and then, sucking and heaving, right at the peak of his healing ritual, brings it up, covered in blood from where he has discreetly bitten his lip, and solemnly presents it to the onlookers as a pathological specimen, extracted from the body of the afflicted patient.
Quesalid had proof of the fakery, he knew the trick as an insider, and was all set to expose those who carried it out; but as part of his training he had to do a bit of clinical work, and he was summoned by a family "who had dreamed of him as their saviour" to see a patient in distress. He did the trick with the tuft, and was appalled, humbled and amazed to find that his patient got better.
Although he continued to maintain a healthy scepticism about most of his colleagues, Quesalid, to his own surprise perhaps, went on to have a long and productive career as a healer and shaman. The anthropologist Claude Levi-Strauss, in his paper "The Sorcerer and his Magic", doesn"t quite know what to make of it: "but it is evident that he carries on his craft conscientiously, takes pride in his achievements, and warmly defends the technique of the b.l.o.o.d.y down against all rival schools. He seems to have completely lost sight of the fallaciousness of the technique which he had so disparaged at the beginning."
Of course, it may not even be necessary to deceive your patient in order to maximise the placebo effect: a cla.s.sic study from 1965-albeit small and without a control group-gives a small hint of what might be possible here. They gave a pink placebo sugar pill three times a day to "neurotic" patients, with good effect, and the explanation given to the patients was startlingly clear about what was going on: A script was prepared and carefully enacted as follows: "Mr. Doe...we have a week between now and your next appointment, and we would like to do something to give you some relief from your symptoms. Many different kinds of tranquilizers and similar pills have been used for conditions such as yours, and many of them have helped. Many people with your kind of condition have also been helped by what are sometimes called "sugar pills", and we feel that a so-called sugar pill may help you, too. Do you know what a sugar pill is? A sugar pill is a pill with no medicine in it at all. I think this pill will help you as it has helped so many others. Are you willing to try this pill?" A script was prepared and carefully enacted as follows: "Mr. Doe...we have a week between now and your next appointment, and we would like to do something to give you some relief from your symptoms. Many different kinds of tranquilizers and similar pills have been used for conditions such as yours, and many of them have helped. Many people with your kind of condition have also been helped by what are sometimes called "sugar pills", and we feel that a so-called sugar pill may help you, too. Do you know what a sugar pill is? A sugar pill is a pill with no medicine in it at all. I think this pill will help you as it has helped so many others. Are you willing to try this pill?" The patient was then given a supply of placebo in the form of pink capsules contained in a small bottle with a label showing the name of the Johns Hopkins Hospital. He was instructed to take the capsules quite regularly, one capsule three times a day at each meal time. The patient was then given a supply of placebo in the form of pink capsules contained in a small bottle with a label showing the name of the Johns Hopkins Hospital. He was instructed to take the capsules quite regularly, one capsule three times a day at each meal time.
The patients improved considerably. I could go on, but this all sounds a bit wishy-washy: we all know that pain has a strong psychological component. What about the more robust stuff: something more counterintuitive, something more...sciencey? Dr Stewart Wolf took the placebo effect to the limit. He took two women who were suffering with nausea and vomiting, one of them pregnant, and told them he had a treatment which would improve their symptoms. In fact he pa.s.sed a tube down into their stomachs (so that they wouldn"t taste the revolting bitterness) and administered ipecac, a drug that which should actually induce induce nausea and vomiting. nausea and vomiting.
Not only did the patients" symptoms improve, but their gastric contractions-which ipecac should worsen-were reduced reduced. His results suggest-albeit it in a very small sample-that a drug could be made to have the opposite effect to what you would predict from the pharmacology, simply by manipulating people"s expectations. In this case, the placebo effect outgunned even the pharmacological influences.
More than molecules?
So is there any research from the basic science of the laboratory bench to explain what"s happening when we take a placebo? Well, here and there, yes, although they"re not easy experiments to do. It"s been shown, for example, that the effects of a real drug in the body can sometimes be induced by the placebo "version", not only in humans, but also in animals. Most drugs for Parkinson"s disease work by increasing dopamine release: patients receiving a placebo treatment for Parkinson"s disease, for example, showed extra dopamine release in the brain.
Zubieta [2005] showed that subjects who are subjected to pain, and then given a placebo, release more endorphins than people who got nothing. (I feel duty bound to mention that I"m a bit dubious about this study, because the people on placebo also endured more painful stimuli, which is another reason why they might have had higher endorphins: consider this a small window into the wonderful world of interpreting uncertain data.) If we delve further into theoretical work from the animal kingdom, we find that animals" immune systems can be conditioned to respond to placebos, in exactly the same way that Pavlov"s dog began to salivate in response to the sound of a bell.
Researchers have measured immune system changes in dogs using just flavoured sugar water, once that flavoured water has been a.s.sociated with immunosuppression, by administering it repeatedly alongside cyclophosphamide, a drug that suppresses the immune system.
A similar effect has been demonstrated in humans, when the researchers gave healthy subjects a distinctively flavoured drink at the same time as cyclosporin A (a drug which measurably reduces your immune function). Once the a.s.sociation was set up with sufficient repet.i.tion, they found that the flavoured drink on its own could induce modest immune suppression. Researchers have even managed to elicit an a.s.sociation between sherbet and natural killer cell activity.
What does this all mean for you and me?
People have tended to think, rather pejoratively, that if your pain responds to a placebo, that means it"s "all in the mind". From survey data, even doctors and nurses buy into this canard. An article from the Lancet Lancet in 1954-another planet in terms of how doctors spoke about patients-states that "for some unintelligent or inadequate patients, life is made easier by a bottle of medicine to comfort the ego". in 1954-another planet in terms of how doctors spoke about patients-states that "for some unintelligent or inadequate patients, life is made easier by a bottle of medicine to comfort the ego".
This is wrong. It"s no good trying to exempt yourself, and pretend that this is about other people, because we all respond to the placebo. Researchers have tried hard in experiments and surveys to characterise "placebo responders", but the results overall come out like a horoscope that could apply to everybody: "placebo responders" have been found to be more extroverted but more neurotic, more well-adjusted but more antagonistic, more socially skilled, more belligerent but more acquiescent, and so on. The placebo responder is everyman. You are a placebo responder. Your body plays tricks on your mind. You cannot be trusted.
How do we draw all this together? Moerman reframes the placebo effect as the "meaning response": "the psychological and physiological effects of meaning in the treatment of illness", and it"s a compelling model. He has also performed one of the most impressive quant.i.tative a.n.a.lyses of the placebo effect, and how it changes with context, again on stomach ulcers. As we"ve said before, this is an excellent disease to study, because ulcers are prevalent and treatable, but most importantly because treatment success can be unambiguously recorded by having a look down there with a gastroscope.
Moerman examined 117 studies of ulcer drugs from between 1975 and 1994, and found, astonishingly, that they interact in a way you would never have expected: culturally, rather than pharmacodynamically. Cimetidine was one of the first ulcer drugs on the market, and it is still in use today: in 1975, when it was new, it eradicated 80 per cent of ulcers, on average, in the various different trials. As time pa.s.sed, however, the success rate of cimetidine deteriorated to just 50 per cent. Most interestingly, this deterioration seems to have occurred particularly after the introduction of ranitidine, a competing and supposedly superior drug, onto the market live years later. So the self-same drug became less effective with time, as new drugs were brought in.
There are a lot of possible interpretations of this. It"s possible, of course, that it was a function of changing research protocols. But a highly compelling possibility is that the older drugs became less effective after new ones were brought in because of deteriorating medical belief in them. Another study from 2002 looked at seventy-five trials of antidepressants over the previous twenty years, and found that the response to placebo has increased significantly in recent years (as has the response to medication), perhaps as our expectations of those drugs have increased.
Findings like these have important ramifications for our view of the placebo effect, and for all of medicine, since it may be a potent universal force: we must remember, specifically, that the placebo effect-or the "meaning effect"-is culturally specific culturally specific.
Brand-name painkillers might be better than blank-box painkillers over here, but if you went and found someone with toothache in 6000 BC, or up the Amazon in 1880, or dropped in on Soviet Russia during the 1970s, where n.o.body had seen the TV advert with the attractive woman wincing from a pulsing red orb of pain in her forehead, who swallows the painkiller, and then the smooth, rea.s.suring blue suffuses her body...in a world without those cultural preconditions to set up the dominoes, you would expect aspirin to do the same job no matter what box it came out of.
This also has interesting implications for the transferability of alternative therapies. The novelist Jeanette Winterson, for example, has written in The Times The Times trying to raise money for a project to treat AIDS sufferers in Botswana-where a quarter of the population is HIV positive-with homeopathy. We must put aside the irony here of taking homeopathy to a country that has been engaged in a water war with neighbouring Namibia; and we must also let lie the tragedy of Botswana"s devastation by AIDS, which is so phenomenal-I"ll say it again: trying to raise money for a project to treat AIDS sufferers in Botswana-where a quarter of the population is HIV positive-with homeopathy. We must put aside the irony here of taking homeopathy to a country that has been engaged in a water war with neighbouring Namibia; and we must also let lie the tragedy of Botswana"s devastation by AIDS, which is so phenomenal-I"ll say it again: a quarter of the population are HIV positive a quarter of the population are HIV positive-that if it is not addressed rapidly and robustly the entire economically active portion of the population could simply cease to exist, leaving what would be effectively a non-country.
Leaving aside all this tragedy, what"s interesting for our purposes is the idea that you could take your Western, individualistic, patient-empowering, anti-medical-establishment and very culturally specific placebo to a country with so little healthcare infrastructure, and expect it to work all the same. The greatest irony of all is that if homeopathy has any benefits at all for AIDS sufferers in Botswana, it may be through its implicit a.s.sociation with the white-coat Western medicine which so many African countries desperately need.
So if you go off now and chat to an alternative therapist about the contents of this chapter-which I very much hope you will-what will you hear? Will they smile, nod, and agree that their rituals have been carefully and elaborately constructed over many centuries of trial and error to elicit the best placebo response possible? That there are more fascinating mysteries in the true story of the relationship between body and mind than any fanciful notion of quantum energy patterns in a sugar pill? To me, this is yet another example of a fascinating paradox in the philosophy of alternative therapists: when they claim that their treatments are having a specific and measurable effect on the body, through specific technical mechanisms rather than ritual, they are championing a very oldfashioned and naive form of biological reductionism, where the mechanics of their interventions, rather than the relationship and the ceremony, have the positive effect on healing. Once again, it"s not just that they have no evidence for their claims about how their treatments work: it"s that their claims are mechanistic, intellectually disappointing, and simply less interesting than the reality.
An ethical placebo?
But more than anything, the placebo effect throws up fascinating ethical quandaries and conflicts around our feelings on pseudoscience. Let"s take our most concrete example so far: are the sugar pills of homeopathy exploitative, if they work only as a placebo? A pragmatic clinician could only consider the value of a treatment by considering it in context.
Here is a clear example of the benefits of placebo. During the nineteenth-century cholera epidemic, deaths were occurring in the London Homeopathic Hospital at just one third of the rate as in the Middles.e.x Hospital, but a placebo effect is unlikely to be all that beneficial in this condition. The reason for homeo-pathy"s success in this case is more interesting: at the time, n.o.body could treat cholera. So while hideous medical practices such as blood-letting were actively harmful, the homeopaths" treatments at least did nothing either way.
Today, similarly, there are often situations where people want treatment, but medicine has little to offer-lots of back pain, stress at work, medically unexplained fatigue and most common colds, to give just a few examples. Going through a theatre of medical treatment, and trying every medication in the book, will give you only side-effects. A sugar pill in these circ.u.mstances seems a very sensible option, as long as it can be administered cautiously, and ideally with a minimum of deceit.
But just as homeopathy has unexpected benefits, so it can have unexpected side-effects. Believing in things which have no evidence carries its own corrosive intellectual side-effects, just as prescribing a pill in itself carries risks: it medicalises problems, as we will see, it can reinforce destructive beliefs about illness, and it can promote the idea that a pill is an appropriate response to a social problem, or, a modest viral illness.
There are also more concrete harms, specific to the culture in which the placebo is given, rather than the sugar pill itself. For example, it"s routine marketing practice for homeopaths to denigrate mainstream medicine. There"s a simple commercial reason for this: survey data shows that a disappointing experience with mainstream medicine is almost the only factor that regularly correlates with choosing alternative therapies. This is not just talking medicine down: one study found that more than half of all the homeopaths approached advised patients against the MMR vaccine for their children, acting irresponsibly on what will quite probably come to be known as the media"s MMR hoax. How did the alternative therapy world deal with this concerning finding, that so many among them were quietly undermining the vaccination schedule? Prince Charles"s office tried to have the lead researcher into the matter sacked.
A BBC Newsnight Newsnight investigation found that almost all the homeopaths approached recommended ineffective homeopathic pills to protect against malaria, and advised against medical malaria prophylactics, while not even giving basic advice on mosquito-bite prevention. This may strike you as neither holistic nor "complementary". How did the self-proclaimed "regulatory bodies" in homeopathy deal with this? None took any action against the homeopaths concerned. investigation found that almost all the homeopaths approached recommended ineffective homeopathic pills to protect against malaria, and advised against medical malaria prophylactics, while not even giving basic advice on mosquito-bite prevention. This may strike you as neither holistic nor "complementary". How did the self-proclaimed "regulatory bodies" in homeopathy deal with this? None took any action against the homeopaths concerned.
And at the extreme, when they"re not undermining public-health campaigns and leaving their patients exposed to fatal diseases, homeopaths who are not medically qualified can miss fatal diagnoses, or actively disregard them, telling their patients grandly to stop using their inhalers, and to throw away their heart pills. There are plenty of examples, but I have too much style to doc.u.ment them here. Suffice to say that while there may be a role for an ethical placebo, homeopaths, at least, have ably demonstrated that they have neither the maturity nor the professionalism to provide it. Fashionable doctors, meanwhile, stunned by the commercial appeal of sugar pills, sometimes wonder-rather unimaginatively-whether they should simply get in on the act and sell some themselves. A smarter idea by far, surely, is to exploit the research we have seen, but only to enhance treatments which really do do perform better than placebo, and improve healthcare without misleading our patients. perform better than placebo, and improve healthcare without misleading our patients.
6 The Nonsense du Jour du Jour
Now we need to raise our game. Food has become, without question, a national obsession. The Daily Mail Daily Mail in particular has become engaged in a bizarre ongoing ontological project, diligently sifting through all the inanimate objects of the universe in order to categorise them as a cause of-or cure for-cancer. At the core of this whole project are a small number of repeated canards, basic misunderstandings of evidence which recur with phenomenal frequency. in particular has become engaged in a bizarre ongoing ontological project, diligently sifting through all the inanimate objects of the universe in order to categorise them as a cause of-or cure for-cancer. At the core of this whole project are a small number of repeated canards, basic misunderstandings of evidence which recur with phenomenal frequency.
Although many of these crimes are also committed by journalists, we will be reviewing them later. For the moment we will focus on "nutritionists", members of a newly invented profession who must create a commercial s.p.a.ce to justify their own existence. In order to do this, they must mystify and overcomplicate diet, and foster your dependence upon them. Their profession is based on a set of very simple mistakes in how we interpret scientific literature: they extrapolate wildly from "laboratory bench data" to make claims about humans; they extrapolate from "observational data" to make "intervention claims"; they "cherry-pick"; and, lastly, they quote published scientific research evidence which seems, as far as one can tell, not to exist.
It"s worth going through these misrepresentations of evidence, mainly because they are fascinating ill.u.s.trations of how people can get things wrong, but also because the aim of this book is that you should be future-proofed against new variants of bulls.h.i.t. There are also two things we should be very clear on. Firstly, I"m picking out individual examples as props, but these are characteristic of the genre; I could have used many more. n.o.body is being bullied, and none of them should be imagined to stand out from the nutritionist crowd, although I"m sure some of the people covered here won"t be able to understand how they"ve done anything wrong.
Secondly, I am not deriding simple, sensible, healthy eating advice. A straightforwardly healthy diet, along with many other aspects of lifestyle (many of which are probably more important, not that you"d know it from reading the papers) is very important. But the media nutritionists speak beyond the evidence: often it is about selling pills; sometimes it is about selling dietary fads, or new diagnoses, or fostering dependence; but it is always driven by their desire to create a market for themselves, in which they are the expert, whereas you are merely bamboozled and ignorant.
Prepare to switch roles.
The four key errors Does the data exist?
This is perhaps the simplest canard of all, and it happens with surprising frequency, in some rather authoritative venues. Here is Michael van Straten on BBC Newsnight Newsnight, talking "fact". If you prefer not to take it on faith that his delivery is earnest, definitive, and perhaps even slightly patrician, you can watch the clip online.
"When Michael van Straten started writing about the magical medicinal powers of fruit juices, he was considered a crank," Newsnight Newsnight begins. "But now he finds he"s at the forefront of fashion." (In a world where journalists seem to struggle with science, we should note that begins. "But now he finds he"s at the forefront of fashion." (In a world where journalists seem to struggle with science, we should note that Newsnight Newsnight has "crank" at one end of the axis, and "fashion" at the other. But that chapter comes later.) Van Straten hands the reporter a gla.s.s of juice. "Two years added to your life expectancy in that!" he chuckles-then a moment of seriousness: "Well, six months, being honest about it." A correction. "A recent study just published last week in America showed that eating pomegranates, pomegranate juice, can actually protect you against ageing, against wrinkles," he says. has "crank" at one end of the axis, and "fashion" at the other. But that chapter comes later.) Van Straten hands the reporter a gla.s.s of juice. "Two years added to your life expectancy in that!" he chuckles-then a moment of seriousness: "Well, six months, being honest about it." A correction. "A recent study just published last week in America showed that eating pomegranates, pomegranate juice, can actually protect you against ageing, against wrinkles," he says.
Hearing this on Newsnight Newsnight, the viewer might naturally conclude that a study has recently been published in America showing that pomegranates can protect against ageing. But if you go to Medline, the standard search tool for finding medical academic papers, no such study exists, or at least not that I can find. Perhaps there"s some kind of leaflet from the pomegranate industry doing the rounds. He goes on: There"s a whole group of plastic surgeons in the States who"ve done a study giving some women pomegranates to eat, and juice to drink, after plastic surgery and before plastic surgery: and they heal in half the time, with half the complications, and no visible wrinkles!" Again, it"s a very specific claim-a human trial on pomegranates and surgery-and again, there is nothing in the studies database.
So could you fairly characterise this Newsnight Newsnight performance as "lying"? Absolutely not. In defence of almost all nutritionists, I would argue that they lack the academic experience, the ill-will, and perhaps even the intellectual horsepower necessary to be fairly derided as liars. The philosopher Professor Harry Frankfurt of Princeton University discusses this issue at length in his cla.s.sic 1986 essay "On Bulls.h.i.t". Under his model, "bulls.h.i.t" is a form of falsehood distinct from lying: the liar knows and cares about the truth, but deliberately sets out to mislead; the truth-speaker knows the truth and is trying to give it to us; the bulls.h.i.tter, meanwhile, does not care about the truth, and is simply trying to impress us: performance as "lying"? Absolutely not. In defence of almost all nutritionists, I would argue that they lack the academic experience, the ill-will, and perhaps even the intellectual horsepower necessary to be fairly derided as liars. The philosopher Professor Harry Frankfurt of Princeton University discusses this issue at length in his cla.s.sic 1986 essay "On Bulls.h.i.t". Under his model, "bulls.h.i.t" is a form of falsehood distinct from lying: the liar knows and cares about the truth, but deliberately sets out to mislead; the truth-speaker knows the truth and is trying to give it to us; the bulls.h.i.tter, meanwhile, does not care about the truth, and is simply trying to impress us: It is impossible for someone to lie unless he thinks he knows the truth. Producing bulls.h.i.t requires no such conviction...When an honest man speaks, he says only what he believes to be true; and for the liar, it is correspondingly indispensable that he considers his statements to be false. For the bulls.h.i.tter, however, all these bets are off: he is neither on the side of the true nor on the side of the false. His eye is not on the facts at all, as the eyes of the honest man and of the liar are, except insofar as they may be pertinent to his interest in getting away with what he says. He does not care whether the things he says describe reality correctly. He just picks them out, or makes them up, to suit his purpose. It is impossible for someone to lie unless he thinks he knows the truth. Producing bulls.h.i.t requires no such conviction...When an honest man speaks, he says only what he believes to be true; and for the liar, it is correspondingly indispensable that he considers his statements to be false. For the bulls.h.i.tter, however, all these bets are off: he is neither on the side of the true nor on the side of the false. His eye is not on the facts at all, as the eyes of the honest man and of the liar are, except insofar as they may be pertinent to his interest in getting away with what he says. He does not care whether the things he says describe reality correctly. He just picks them out, or makes them up, to suit his purpose.
I see van Straten, like many of the subjects in this book, very much in the "bulls.h.i.tting" camp. Is it unfair for me to pick out this one man? Perhaps. In biology fieldwork, you throw a wired square called a "quadrat" at random out onto the ground, and then examine whatever species fall underneath it. This is the approach I have taken with nutritionists, and until I have a Department of Pseudoscience Studies with an army of PhD students doing quant.i.tative work on who is the worst, we shall never know. Van Straten seems like a nice, friendly guy. But we have to start somewhere.
Observation, or intervention?
Does the c.o.c.k"s crow cause the sun to rise? No. Does this light switch make the room get brighter? Yes. Things can happen at roughly the same time, but that is weak, circ.u.mstantial evidence for causation. Yet it"s exactly this kind of evidence that is used by media nutritionists as confident proof of their claims in our second major canard.
According to the Daily Mirror Daily Mirror, Angela Dowden, RNutr, is "Britain"s Leading Nutritionist", a monicker it continues to use even though she has been censured by the Nutrition Society for making a claim in the media with literally no evidence whatsoever. Here is a different and more interesting example from Dowden: a quote from her column in the Mirror Mirror, writing about foods offering protection from the sun during a heatwave: "An Australian study in 2001 found that olive oil (in combination with fruit, vegetables and pulses) offered measurable protection against skin wrinkling. Eat more olive oil by using it in salad dressings or dip bread in it rather than using b.u.t.ter."
That"s very specific advice, with a very specific claim, quoting a very specific reference, and with a very authoritative tone. It"s typical of what you get in the papers from media nutritionists. Let"s go to the library and fetch out the paper she refers to ("Skin wrinkling: can food make a difference?" Purba MB et al. J Am Coll Nutr J Am Coll Nutr. 2001 Feb; 20(1): 71-80). Before we go any further, we should be clear that we are criticising Dowden"s interpretation interpretation of this research, and not the research itself, which we a.s.sume is a faithful description of the investigative work that was done. of this research, and not the research itself, which we a.s.sume is a faithful description of the investigative work that was done.
This was an observational study, not an intervention study. It did not give people olive oil for a time and then measure differences in wrinkles: quite the opposite, in fact. It pooled four different groups of people to get a range of diverse lifestyles, including Greeks, Anglo-Celtic Australians and Swedish people, and it found that people who had completely different eating habits-and completely different lives, we might reasonably a.s.sume-also had different amounts of wrinkles.
To me this is not a great surprise, and it ill.u.s.trates a very simple issue in epidemiological research called "confounding variables": these are things which are related both to the outcome you"re measuring (wrinkles) and to the exposure you are measuring (food), but which you haven"t thought of yet. They can confuse an apparently causal relationship, and you have to think of ways to exclude or minimise confounding variables to get to the right answer, or at least be very wary that they are there. In the case of this study, there are almost too many confounding variables to describe.
I eat well-with lots of olive oil, as it happens-and I don"t have many wrinkles. I also have a middlecla.s.s background, plenty of money, an indoor job, and, if we discount infantile threats of litigation and violence from people who cannot tolerate any discussion of their ideas, a life largely free from strife. People with completely different lives will always have different diets, and different wrinkles. They will have different employment histories, different amounts of stress, different amounts of sun exposure, different levels of affluence, different levels of social support, different patterns of cosmetics use, and much more. I can imagine plenty of reasons why you might find that people who eat olive oil have fewer wrinkles; and the olive oil having a causative role, an actual physical effect on your skin when you eat it, is fairly low down on my list.
Now, to be fair to nutritionists, they are not alone in failing to understand the importance of confounding variables, in their eagerness for a clear story. Every time you read in a newspaper that "moderate alcohol intake" is a.s.sociated with some improved health outcome-less heart disease, less obesity, anything-to gales of delight from the alcohol industry, and of course from your friends, who say, "Ooh well, you see, it"s better for me to drink a little..." as they drink a lot-you are almost certainly witnessing a journalist of limited intellect, overinterpreting a study with huge confounding variables.
This is because, let"s be honest here: teetotallers are abnormal. They"re not like everyone else. They will almost certainly have a reason for not drinking, and it might be moral, or cultural, or perhaps even medical, but there"s a serious risk that whatever is causing them to be teetotal might also have other effects on their health, confusing the relationship between their drinking habits and their health outcomes. Like what? Well, perhaps people from specific ethnic groups who are teetotal are also more likely to be obese, so they are less healthy. Perhaps people who deny themselves the indulgence of alcohol are more likely to indulge in chocolate and chips. Perhaps preexisting ill health will force you to give up alcohol, and that"s skewing the figures, making teetotallers look unhealthier than moderate drinkers. Perhaps these teetotallers are recovering alcoholics: among the people I know, they"re the ones who are most likely to be absolute teetotallers, and they"re also more likely to be fat, from all those years of heavy alcohol abuse. Perhaps some of the people who say they are teetotal are just lying.
This is why we are cautious about interpreting observational data, and to me, Dowden has extrapolated too far from the data, in her eagerness to dispense-with great authority and certainty-very specific dietary wisdom in her newspaper column (but of course you may disagree, and you now have the tools to do so meaningfully). specific dietary wisdom in her newspaper column (but of course you may disagree, and you now have the tools to do so meaningfully).
If we were modern about this, and wanted to offer constructive criticism, what might she have written instead? I think, both here and elsewhere, that despite what journalists and self-appointed "experts" might say, people are perfectly capable of understanding the evidence for a claim, and anyone who withholds, overstates or obscures that evidence, while implying that they"re doing the reader a favour, is probably up to no good. MMR is an excellent parallel example of where the bl.u.s.ter, the panic, the "concerned experts" and the conspiracy theories of the media were very compelling, but the science itself was rarely explained.
So, leading by example, if I were a media nutritionist, I might say, if pushed, after giving all the other sensible sun advice: "A survey found that people who eat more olive oil have fewer wrinkles," and I might feel obliged to add, "Although people with different diets may differ in lots of other ways." But then, I"d also be writing about food, so: "Never mind, here"s a delicious recipe for salad dressing anyway." n.o.body"s going to employ me to write a nutritionist column.
From the lab bench to the glossies Nutritionists love to quote basic laboratory science research because it makes them look as if they are actively engaged in a process of complicated, impenetrable, highly technical academic work. But you have to be very cautious about how you extrapolate from what happens to some cells in a dish, on a laboratory bench, to the complex system of a living human being, where things can work in completely the opposite way to what laboratory work would suggest. Anything can kill cells in a test tube. Fairy Liquid will kill cells in a test tube, but you don"t take it to cure cancer. This is just another example of how nutri-tionism, despite the "alternative medicine" rhetoric and phrases like "holistic", is actually a crude, unsophisticated, old fashioned, and above all reductionist reductionist tradition. tradition.
Later we will see Patrick Holford, the founder of the Inst.i.tute for Optimum Nutrition, stating that vitamin C is better than the AIDS drug AZT on the basis of an experiment where vitamin C was tipped onto some cells in a dish. Until then, here is an example from Michael van Straten-who has fallen sadly into our quadrat, and I don"t want to introduce too many new characters or confuse you-writing in the Daily Express Daily Express as its nutrition specialist: "Recent research", he says, has shown that turmeric is "highly protective against many forms of cancer, especially of the prostate". It"s an interesting idea, worth pursuing, and there have been some speculative lab studies of cells, usually from rats, growing or not growing under microscopes, with turmeric extract tipped on them. There is some limited animal model data, but it is not fair to say that turmeric, or curry, in the real world, in real people, is "highly protective against many forms of cancer, especially of the prostate", least of all because it"s not very well absorbed. as its nutrition specialist: "Recent research", he says, has shown that turmeric is "highly protective against many forms of cancer, especially of the prostate". It"s an interesting idea, worth pursuing, and there have been some speculative lab studies of cells, usually from rats, growing or not growing under microscopes, with turmeric extract tipped on them. There is some limited animal model data, but it is not fair to say that turmeric, or curry, in the real world, in real people, is "highly protective against many forms of cancer, especially of the prostate", least of all because it"s not very well absorbed.
Forty years ago a man called Austin Bradford-Hill, the grandfather of modern medical research, who was key in discovering the link between smoking and lung cancer, wrote out a set of guidelines, a kind of tick list, for a.s.sessing causality, and a relationship between an exposure and an outcome. These are the cornerstone of evidence-based medicine, and often worth having at the back of your mind: it needs to be a strong a.s.sociation, which is consistent, and specific to the thing you are studying, where the putative cause comes before the supposed effect in time; ideally there should be a biological gradient, such as a dose-response effect; it should be consistent, or at least not completely at odds with, what is already known (because extraordinary claims require extraordinary evidence); and it should be biologically plausible.
Michael van Straten, here, has got biological plausibility, and little else. Medics and academics are very wary of people making claims on such tenuous grounds, because it"s something you get a lot from people with something to sell: specifically, drug companies. The public don"t generally have to deal with drug-company propaganda, because the companies are not currently allowed to talk to patients in Europe-thankfully-but they badger doctors incessantly, and they use many of the same tricks as the miracle-cure industries. You"re taught about these tricks at medical school, which is how I"m able to teach you about them now.
Drug companies are very keen to promote theoretical advantages ("It works more on the Z4 receptor, so it must have fewer side-effects!"), animal experiment data or "surrogate outcomes" ("It improves blood test results, it must be protective against heart attacks!") as evidence of the efficacy or superiority of their product. Many of the more detailed popular nutritionist books, should you ever be lucky enough to read them, play this cla.s.sic drug-company card very a.s.sertively. They will claim, for example, that a "placebo-controlled randomised control trial" has shown benefits benefits from a particular vitamin, when what they mean is, it showed changes in a "surrogate outcome". from a particular vitamin, when what they mean is, it showed changes in a "surrogate outcome".
For example, the trial may merely have shown that there were measurably increased amounts of the vitamin in the bloodstream after taking a vitamin, compared to placebo, which is a pretty unspectacular finding in itself: yet this is presented to the unsuspecting lay reader as a positive trial. Or the trial may have shown that there were changes in some other blood marker, perhaps the level of an ill-understood immune-system component, which, again, the media nutritionist will present as concrete evidence of a real-world benefit.
There are problems with using such surrogate outcomes. They are often only tenuously a.s.sociated with the real disease, in a very abstract theoretical model, and often developed in the very idealised world of an experimental animal, genetically inbred, kept under conditions of tight physiological control. A surrogate outcome can-of course-be used to generate and examine hypotheses about a real disease in a real person, but it needs to be very carefully validated. Does it show a clear dose-response relationship? Is it a true predictor of disease, or merely a "co-variable", something that is related to the disease in a different way (e.g. caused by by it rather than involved in it rather than involved in causing causing it)? Is there a well-defined cut-off between normal and abnormal values? it)? Is there a well-defined cut-off between normal and abnormal values?
All I am doing, I should be clear, is taking the feted media nutritionists at their own word: they present themselves as men and women of science, fill their columns, TV shows and books with references to scientific research. I am subjecting their claims to the exact same level of very basic, uncomplicated rigour that I would deploy for any new theoretical work, any drug company claim and pill marketing rhetoric, and so on.
It"s not unreasonable to use surrogate outcome data, as they do, but those who are in the know are always circ.u.mspect. We"re interested interested in early theoretical work, but often the message is: "It might be a bit more complicated than that...". You"d only want to accord a surrogate outcome any significance if you"d read everything on it yourself, or if you could be absolutely certain that the person a.s.suring you of its validity was extremely capable, and was giving a sound appraisal of all the research in a given field, and so on. in early theoretical work, but often the message is: "It might be a bit more complicated than that...". You"d only want to accord a surrogate outcome any significance if you"d read everything on it yourself, or if you could be absolutely certain that the person a.s.suring you of its validity was extremely capable, and was giving a sound appraisal of all the research in a given field, and so on.
Similar problems arise with animal data. n.o.body could deny that this kind of data is valuable in the theoretical domain, for developing hypotheses, or suggesting safety risks, when cautiously appraised. But media nutritionists, in their eagerness to make lifestyle claims, are all too often blind to the problems of applying these isolated theoretical nuggets to humans, and anyone would think they were just trawling the internet looking for random bits of science to sell their pills and expertise (imagine that). Both the tissue and the disease in an animal model, after all, may be very different to those in a living human system, and these problems are even greater with a lab-dish model. Giving unusually high doses of chemicals to animals can distort the usual metabolic pathways, and give misleading results-and so on. Just because something can upregulate or downregulate something in a model doesn"t mean it will have the effect you expect in a person-as we will see with the stunning truth about antioxidants.
And what about turmeric, which we were talking about before I tried to show you the entire world of applying theoretical research in this tiny grain of spice? Well, yes, there is some evidence that curc.u.min, a chemical in turmeric, is highly biologically active, in all kinds of different ways, on all kinds of different systems (there are also theoretical grounds for believing that it may be carcinogenic, mind you). It"s certainly a valid target for research.
But for the claim that we should eat more curry in order to get more of it, that "recent research" has shown it is "highly protective against many forms of cancer, especially of the prostate", you might want to step back and put the theoretical claims in the context of your body. Very little of the curc.u.min you eat is absorbed. You have to eat a few grams of it to reach significant detectable serum levels, but to get a few grams of curc.u.min curc.u.min, you"d have to eat 100g of turmeric turmeric: and good luck with that. Between research and recipe, there"s a lot more to think about than the nutritionists might tell you.
Cherry-picking The idea is to try and give all the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another. The idea is to try and give all the information to help others to judge the value of your contribution; not just the information that leads to judgment in one particular direction or another. Richard P. Feynman Richard P. Feynman There have been an estimated fifteen million medical academic articles published so far, and 5,000 journals are published every month. Many of these articles will contain contradictory claims: picking out what"s relevant-and what"s not-is a gargantuan task. Inevitably people will take shortcuts. We rely on review articles, or on meta-a.n.a.lyses, or textbooks, or hearsay, or chatty journalistic reviews of a subject.
That"s if your interest is in getting to the truth of the matter. What if you"ve just got a point to prove? There are few opinions so absurd that you couldn"t find at least one person with a PhD somewhere in the world to endorse them for you; and similarly, there are few propositions in medicine so ridiculous that you couldn"t conjure up some kind of published experimental evidence somewhere to support them, if you didn"t mind it being a tenuous relationship, and cherry-picked the literature, quoting only the studies that were in your favour.
One of the great studies of cherry-picking in the academic literature comes from an article about Linus Pauling, the greatgrandfather of modern nutritionism, and his seminal work on vitamin C and the common cold. In 1993 Paul Knipschild, Professor of Epidemiology at the University of Maastricht, published a chapter in the mighty textbook Systematic Reviews Systematic Reviews: he had gone to the extraordinary trouble of approaching the literature as it stood when Pauling was working, and subjecting it to the same rigorous systematic review that you would find in a modern paper.
He found that while some trials did suggest that vitamin C had some benefits, Pauling had selectively quoted from the literature to prove his point. Where Pauling had referred to some trials which seriously challenged his theory, it was to dismiss them as methodologically flawed: but as a cold examination showed, so too were papers he quoted favourably in support of his own case.
In Pauling"s defence, his was an era when people knew no better, and he was probably quite unaware of what he was doing: but today cherry-picking is one of the most common dubious practices in alternative therapies, and particularly in nutrition-ism, where it seems to be accepted essentially as normal practice (it is this cherry-picking, in reality, which helps to characterise what alternative therapists conceive of rather grandly as their "alternative paradigm"). It happens in mainstream medicine also, but with one crucial difference: there it is recognised as a major problem, and hard work has been done to derive a solution.
That solution is a process called "systematic review". Instead of just mooching around online and picking out your favourite papers to back up your prejudices and help you sell a product, in a systematic review you have an explicit search strategy for seeking out data (openly described in your paper, even including the search terms you used on databases of research papers), you tabulate the characteristics of each study you find, you measure-ideally blind to the results-the methodological quality of each one (to see how much of a "fair test" it is), you compare alternatives, and then finally you give a critical, weighted summary.
This is what the Cochrane Collaboration does on all the healthcare topics that it can find. It even invites people to submit new clinical questions that need an answer. This careful sifting of information has revealed huge gaps in knowledge, it has revealed that "best practices" were sometimes murderously flawed, and simply by sifting methodically through pre-existing data, it has saved more lives than you could possibly imagine. In the nineteenth century, as the public-health doctor Muir Gray has said, we made great advances through the provision of clean, clear water; in the twenty-first century we will make the same advances through clean, clear information. Systematic reviews are one of the great ideas of modern thought. They should be celebrated.
Problematising antioxidants We have seen the kinds of errors made by those in the nutri-tionism movement as they strive to justify their more obscure and technical claims. What"s more fun is to take our new understanding and apply it to one of the key claims of the nutrition-ism movement, and indeed to a fairly widespread belief in general: the claim that you should eat more antioxidants.
As you now know, there are lots of ways of deciding whether the totality of research evidence for a given claim stacks up, and it"s rare that one single piece of information clinches it. In the case of a claim about food, for example, there are all kinds of different things we might look for: whether it is theoretically plausible, whether it is backed up by what we know from observing diets and health, whether it is supported by "intervention trials" where we give one group one diet and another group a different one, and whether those trials measured real-world outcomes, like "death", or a surrogate outcome, like a blood test, which is only hypothetically related to a disease.
My aim here is by no means to suggest that antioxidants are entirely entirely irrelevant to health. If I had a Tshirt slogan for this whole book it would be: "I think you"ll find it"s a bit more complicated than that". I intend, as they say, to "problematise" the prevailing nutritionist view on antioxidants, which currently lags only about twenty years behind the research evidence. irrelevant to health. If I had a Tshirt slogan for this whole book it would be: "I think you"ll find it"s a bit more complicated than that". I intend, as they say, to "problematise" the prevailing nutritionist view on antioxidants, which currently lags only about twenty years behind the research evidence.
From an entirely theoretical perspective, the idea that antioxidants are beneficial for health is an attractive one. When I was a medical student-not so long ago-the most popular biochemistry textbook was called Stryer. This enormous book is filled with complex interlocking flow charts of how chemicals-which is what you are made of-move through the body. It shows how different enzymes break down food into its const.i.tuent molecular elements, how these are absorbed, how they are rea.s.sembled into new larger molecules that your body needs to build muscles, retina, nerves, bone, hair, membrane, mucus, and everything else that you"re made of; how the various forms of fats are broken down, and rea.s.sembled into new forms of fat; or how different forms of molecule-sugar, fat, even alcohol-are broken down gradually, step by step, to release energy, and how that energy is transported, and how the incidental products from that process are used, or bolted onto something else to be transported in the blood, and then ditched at the kidneys, or metabolised down into further const.i.tuents, or turned into something useful elsewhere, and so on. This is on