麻豆传媒

DAVID is 16 years old. He spends around 20 hours a day in a shared cell that contains nothing more than a cramped bunk bed and a toilet. His evening鈥檚 entertainment consists of eating a pre-packed breakfast intended for the following morning. Once that鈥檚 gone, he鈥檒l get no more food until lunchtime the next day. The mind-numbing tedium of David鈥檚 life is broken by fewer than 18 hours of purposeful activity a week. This is the reality of life inside a young offenders institution in Britain today. Little wonder, then, that antisocial behaviour is rife.

Politicians like to claim that they鈥檙e 鈥渢ough on crime, tough on the causes of crime鈥�. But what are the causes of crime? Broken homes, poor education and poverty are often implicated, yet many people survive all of these without so much as a parking ticket. A group of British researchers now claim that a huge amount of antisocial behaviour is simply down to poor nutrition. Their research suggests that a daily dose of vitamins, minerals and fatty acids could stem the tidal wave of crime that threatens to swamp the prison system, and perhaps society at large.

It鈥檚 an astounding claim that has been met with widespread scepticism. If the researchers are right, they have succeeded where generations of politicians have failed, finding a cheap and easy way to reduce crime and antisocial behaviour. So is there anything in it?

The research was funded and organised by Natural Justice, a charity that researches the causes of criminal behaviour. Its director is Bernard Gesch, a senior researcher in the physiology department at Oxford University. 鈥淧eople assume that antisocial behaviour is entirely a problem of personality,鈥� he explains. 鈥淏ut there is a whole substratum of physiological factors that can be measured scientifically.鈥� He believes many prisoners are suffering from 鈥渟ubclinical malnutrition鈥� 鈥� not bad enough to bring on physical symptoms such as scurvy, but enough to cause a range of antisocial behaviours.

Natural Justice鈥檚 research programme began in 1988 when Gesch persuaded magistrates in Cumbria in northwest England to let him try nutrition supplements on a juvenile offender who had resisted all other attempts at rehabilitation. He says the result was a sudden improvement in the subject鈥檚 behaviour. In a second case study, Natural Justice claims to have halted one girl鈥檚 criminal career just by raising her intake of micronutrients to the government鈥檚 recommended daily allowance (RDA). Perhaps these weren鈥檛 fundamentally bad kids. Maybe they were just malnourished.

The latest Natural Justice study was carried out over 9 months at a young offenders institution in Aylesbury, Buckinghamshire. It followed the behaviour of 231 inmates 鈥� about 75 per cent of the prison鈥檚 total population over that period 鈥� by monitoring the number of official reports of bad behaviour they received from prison staff. Half the prisoners took daily nutrient supplements containing 28 vitamins, minerals and fatty acids (see Table), while the rest were given placebo pills. The researchers used all the methods of a rigorous medical study to ensure the results were reliable. For example, the trial was 鈥渄ouble blind鈥� so that neither prisoners nor guards knew who got the real pills and who the dummies. And it was randomised, so that the prisoners on the real pills were scattered throughout the prison, not just grouped into one wing. About sixty prisoners dropped out of the trial, mostly because they were transferred or released, but statistical analysis weeded out any anomalies that this might have caused.

The results were startling. Prisoners taking the nutrient pills committed 37 per cent fewer serious or violent offences than the placebo group. When the trial finished, levels of violence quickly returned to normal. When the results were published in the British Journal of Psychiatry earlier this year (vol 181, p 22), Natural Justice called a press conference. A flurry of media reports about crime-busting pills soon followed, many highlighting not just the prison experiments, but also the possibility that rising levels of violence in society at large were caused by bad nutrition.

Not surprisingly, many scientists are wary of reading too much into the results. Professor Chris Bates of the Medical Research Council鈥檚 Human Nutrition Unit in Cambridge proffers a typical view: 鈥淥ne always has to retain a position of scepticism until at least one and possibly more replications produce the same result,鈥� he says. David Benton of Swansea University, who studies the link between diet and mood, adds: 鈥淧rison is a setting that magnifies the effect of diet because the environment is relatively similar for all, so dietary changes have an impact that would not be apparent elsewhere. It鈥檚 unlikely that you could demonstrate an impact of a similar magnitude in the outside world.鈥� And Susan Jebb, also at the Human Nutrition Unit, points out that there are many badly behaved children who have good diets, so it鈥檚 clearly not at the root of all antisocial behaviour.

However, many highly respected scientists believe the research has profound implications. 鈥淚 do think that this is a finding that needs to be taken seriously, and deserves further research,鈥� says Bates. Peter Rogers, a psychology professor at Bristol University who researches the psychological effects of diet, says the Aylesbury effect is a 鈥渞emarkable result and potentially very important. In my view it would be premature to conclude from this one study that dietary improvements will have a major impact on violent behaviour in our society, but clearly improving the nutritional quality of diets in prisons would be a good thing in many ways.鈥�

Although the Aylesbury experiment has been hailed as ground-breaking, similar studies have been carried out over the past 25 years. Stephen Schoenthaler, a criminologist at California State University in Long Beach who is one of the leading proponents of a link between diet and crime, has completed three trials with similar results. 鈥淭he Aylesbury study independently verifies what I鈥檝e been advocating for 20 years,鈥� he says.

Schoenthaler鈥檚 studies have been accused of employing flawed methodology, however, and Schoenthaler himself is a controversial figure. So how does the Aylesbury study compare? There have been criticisms of its methodology, for example from Juliet Lyons, director of Britain鈥檚 Prison Reform Trust, who points out that any form of contact with a caring adult 鈥� even a quick chat while giving a pill 鈥� could have a big impact on behaviour. Gesch, however, argues that the study design eliminated this possibility. The control group received exactly the same amount of contact when they were given their placebo pills, but their behaviour didn鈥檛 improve significantly.

Perhaps the most strident critic of the link between diet and crime is Susan Pease, professor of criminology at Central Connecticut State University in New Britain. In 1988, she co-authored an influential review on diet and behaviour prepared for the US Justice Department which concluded that there wasn鈥檛 enough evidence to recommend policy changes. Pease also raises concerns about the methodology of the Aylesbury study. 鈥淢any of these 鈥榬eports鈥� are down to the interpretation of officers,鈥� she says. 鈥淎s someone who has spent a lot of time in prisons doing research, I have found that less serious violations can include such things as 鈥榝ailure to make one鈥檚 bed properly鈥� or 鈥榳alking outside of the clearly marked taped areas in the corridors鈥�. These hardly constitute antisocial behaviour in the real world.鈥� Natural Justice, however, points out that the 37 per cent reduction was in 鈥済overnor reports鈥� covering serious offences that can cost a prisoner parole, such as those involving violence, and not 鈥渕inor reports鈥� for failing to comply with rules.

Overall, the methodology of the Aylesbury experiment looks secure. John Copas, professor of statistics at the University of Warwick and former vice-president of Britain鈥檚 Royal Statistical Society, says: 鈥淚n clinical research, this study鈥檚 design would be accepted as the gold standard and the only scientifically sound way of assessing cause and effect. But in social and behaviour research this rigour is, in my experience, pretty unusual.鈥�

It鈥檚 right to be sceptical when a group like Natural Justice bolsters its own raison d鈥櫭猼re by showing that crime is closely linked to diet. This may have been a factor in both Nature and Science rejecting the manuscript of Gesch鈥檚 study, although a Nature insider points out that the journal rarely publishes psychological studies, especially when there is no exploration of the biological basis for a particular behaviour.

The absence of a physiological explanation for a link between diet and crime is clearly a problem. 鈥淥ne of the big issues is that they鈥檝e used a very generic supplement,鈥� says Jebb. 鈥淚t has so many components, we can鈥檛 even begin to look at the mechanisms involved.鈥� She points out that the effects of a nutritional supplement may be very different depending on whether you are just raising people鈥檚 intake to the RDA, or whether you are boosting them beyond that by supplementing an already adequate diet. 鈥淭he dietary data from the study isn鈥檛 really good enough to tell you that.鈥�

Gesch points out that he鈥檚 not advocating huge doses of anything, merely ensuring that the inmates reach the nutritional levels recommended by government scientists. But he admits there was nothing in the study to explain how the supplements might work. 鈥淭he study was only set up to ask if nutrition affected behaviour. The next stage is to study how nutrition affects behaviour,鈥� he says.

Although nutritionists admit they know very little about how diet affects our brain, they agree that omega-3 fatty acids, found primarily in oily fish such as tuna and mackerel, are important for the brain鈥檚 production of the mood-altering neurotransmitter serotonin (麻豆传媒, 24 August, p 34). Joseph Hibbeln of the US National Institute on Alcoholism and Alcohol Abuse in Bethesda, Maryland, says: 鈥淚t is plausible that providing these prisoners with essential fatty acids improved the functioning of their serotonergic nervous system.鈥�

Vitamins often help to speed up chemical reactions in the brain. For example, vitamin B₆ is important in the synthesis of many amino acid neurotransmitters, while vitamin B₃ is essential for generating energy. 鈥淥ur diet supplies the brain with its energy and the building blocks of all the neurotransmitters it uses,鈥� says Gesch. He argues that if someone鈥檚 diet is poor, then their brain is not going to work properly. One plausible outcome is antisocial behaviour.

Natural Justice is already planning a follow-up study to pin down exactly how these micronutrients affect physiology. Gesch is working with the MRC Human Nutrition Unit and the Home Office to devise an experiment that will tell him what is actually going on in prisoners鈥� brains when they receive the pills. They hope that blood samples and metabolite tests will finally provide some answers. The research will also investigate whether young offenders would be better served by simply eating more fruit and vegetables.

Researchers have been building up to the conclusion that diet may influence criminal behaviour for more than 20 years, so it seems odd that governments have failed to try any policy experiments based on this evidence. In fact, some prisons in the US have banned supplements following the Violent Criminal Incarceration Act of 1995, which bars prisoners from undertaking 鈥渁ny physical activities designed to increase their fighting ability鈥�.

A Home Office spokesman says the British government is still 鈥渓ooking at the Aylesbury research鈥�, suggesting that policy changes aren鈥檛 imminent. Bates thinks this is a prudent approach, given the current state of knowledge. 鈥淩esearch in this area does take a very long time to come up with a cut-and-dried answer. There is no quick fix.鈥�

Pease also wants proof that supplements have a real biological effect. 鈥淲ithout that, any change in policy would be foolhardy,鈥� she says. Jebb agrees that caution is necessary. 鈥淭here鈥檚 been a lot of debate about whether we should do another, larger study or whether we should simply implement the findings now. Some parts of the media have called for an immediate policy change. We feel that you need to justify any policy change with a larger, more detailed scientific study.鈥�

Even Schoenthaler, who is something of an evangelist for the idea of solving social problems by improving diet, is keen to point out that this will not work for everybody. In studies of more than 8000 young offenders, he found that a change in diet affected only about 20 per cent of them. In other words, most behavioural problems were not due to dietary deficiencies. However, he says, most crimes are committed by a small, underprivileged section of society, and it is these people who are most likely to be malnourished. So by improving the behaviour of a fifth of all offenders through dietary changes you could significantly reduce crime.

Another reason for caution is that there are risks associated with certain supplements. Britain鈥檚 Food Standards Agency has just published a report that tries to establish maximum safety levels for vitamins and minerals. For example, excessive consumption of vitamin B₆, which many women take to relieve premenstrual syndrome, can damage the nervous system.

Cost is also a problem. Supplementing a single prisoner鈥檚 diet cost about 拢1 a day, but Britain鈥檚 prisons budget currently allows for just 拢1.49 a day on food for a young offender.

Finally, forcing prisoners to take supplements raises ethical questions. Susan Pease points out that no one advocates handing out Prozac to prisoners even though doing so would probably reduce violence. Is there any moral difference in using vitamins to achieve the same effect?

Gesch, however, believes there is already a good argument for raising dietary standards in the wider community. 鈥淚f this works in prisons, there鈥檚 no reason why it shouldn鈥檛 work in schools too,鈥� he says. British schools are clearly having difficulty controlling their pupils鈥� behaviour. The past school year saw more than 9000 pupils expelled from state schools because of bad behaviour, an 11 per cent increase on the previous year. Schoenthaler has already tried diet supplements in American schools, with much success. In fact, many schools in the US are now setting up micronutrient programmes for themselves.

Even if Natural Justice can prove exactly how a bad diet causes criminal behaviour, it may then face a whole new set of problems. In a legal system based on the concept of free will, individuals are deemed to be responsible for their own behaviour. If criminal behaviour can indeed be caused by poor nutrition, Natural Justice鈥檚 research may give young offenders an excuse for their misdemeanours. In a few years鈥� time, we could be hearing the first 鈥渇ast food鈥� defence: 鈥淒on鈥檛 blame me, my diet made me do it.鈥�