Summer's explosion of violence, greed and antisocial behaviour across the UK was disturbing on many different levels. But now that the dust has settled,Dr Alex Richardsonholds a persuasive argument that we need to develop an appetite for addressing such behaviours by improving our diets through good nutrition - and that we simply can't afford not to do so
Dr Alex Richardson Senior Research Fellow
University of Oxford, Founder Director of UK charity Food and Behaviour ResearchLearning problems and antisocial behaviour have reached record levels in the UK, as illustrated by the recent riots in London and other cities.
Politicians and social commentators may widely disagree on the "causal factors", but poverty, social deprivation, poor parenting, lack of family or community support are phrases that commonly crop up to "explain" such behaviours. Although certain individuals involved in antisocial behaviour may indeed have troubled backgrounds, the links with psychosocial factors are entirely correlational, and "evidence" for actual causes is largely lacking. However, clearer evidence thatdoesindicate causality can be found in one area that's often overlooked: nutrition. A rigorous randomised, double-blind placebo controlled trial conducted in a UK prison for Young Offenders provided compelling evidence for a link between diet and antisocial behaviour1. Simply improving their nutritional status (using a dietary supplement providing only recommended daily intakes of vitamins, minerals and essential fatty acids) reduced proven disciplinary incidents by 26 per cent over the nine-month trial period, and violent incidents by almost 40 per cent. The placebo-treated group showed no change on either measure.
A similar, study commissioned by the Dutch Ministry of Justice also found benefits from nutritional supplementation of young offenders2. Yet nutrition and diet were barely mentioned in the extensive debates following the recent UK riots.
Childhood disorders of behaviour, learning and mood: a growing problem
Antisocial behaviour is highly correlated with other forms of behavioural or learning disorders, so it's worth taking a moment to consider some of these.
- Attention-deficit hyperactivity disorder (ADHD) - characterised by serious hyperactivity, impulsivity and/or difficulties with attention and concentration - now affects at least one in every 20 children in the UK. Conduct Disorder and Oppositional Defiant Disorder show high comorbidity with ADHD (although of course all of these "diagnoses" are based purely on descriptive criteria, hence many people maintain that all of these labels are simply excuses for "bad behaviour".)
- Autistic spectrum disorders - involving deficits in social and communication skills as well as behavioural problems - now affect one or two children in every 100, whereas 50 years ago it was one or two in 10,000.
- At least one in every 10 children has either specific difficulties with literacy skills (dyslexia), or with motor coordination, organisation and planning (dyspraxia), or both - limiting their educational, social and future employment opportunities.
School and Local Education Authority (LEA) records in the UK show that one in every five children now has Special Educational Needs - mostly of these kinds - needing additional support to benefit from mainstream education. Most will receive no formal diagnosis, however, nor special help, because the resources are simply not available. Add to this the fact that international surveys have shown UK children to be among the unhappiest in Europe, with escalating rates of depression, anxiety disorders and deliberate self-harm, and it is clear that there is huge room for improvement when it comes to factors affecting children's behaviour, learning and mood.
The poor state of children's diets
So why do we continue to ignore the fundamental issue of nutrition when it comes to children's brains and behaviour? We have ample evidence that the typical modern, western-type diet is detrimental to physical health - as evidenced by the epidemics of childhood obesity and Type 2 diabetes. The brain is part of the body - and a priori, it is more than likely that any diet that is bad for the body will also be bad for the brain. We already know that children's diets in the UK are far from optimal, at the levels of both "macronutrients" (protein, fat, carbohydrate and dietary fibre) and "micronutrients" (vitamins, minerals and essential fatty acids)3. Soft drinks, sweets, confectionery, crisps, biscuits, cakes, ice cream and other highly processed foods have literally displaced fruits and vegetables, severely distorting the balance of children's diets compared with official recommendations.
Most children consume far too little dietary fibre - reflecting their low intake of fruit, vegetables and whole grains. Fibre is essential to support the "good bacteria" needed for both digestive and immune system health (while the sugary foods and drinks they do consume encourage the growth of "bad bacteria" and yeasts). Poor gut health leads to many more problems than just unpleasant gastrointestinal symptoms. It compromises digestion (and therefore the absorption of essential nutrients), and also impairs immune system functioning. It can also affect brains and behaviour, because the gut, brain and immune system share many of the same chemical signalling molecules. The gut flora are only just beginning to be recognised by medical science as an extraordinarily complex ecosystem that affects every aspect of our health and wellbeing - including our mental wellbeing.
Food industrialisation and its effect on nutrition
Industrialisation of food is a large part of the problem because good foods make bad commodities, and good commodities make bad foods. Sugar and refined starches (which make up an excessive proportion of children's total energy intake) have little or no nutritional value beyond their calorie content. The fibre and essential nutrients in the foods from which they are derived have been discarded (in the interests of shelf life, and food industry profits). We have done the same to fats and oils. Hydrogenated vegetable oils (which contain toxic trans fats - ie: twisted versions of the natural omega-3 and omega-6 essential fatty acids)displaced more expensive animal fats like butter or lard from the 1960s until very recently. These toxic fats are still used in many processed foods, snacks and takeaways; foods disproportionately consumed by young people, and those on low incomes. They are likely to be most heavily consumed in just the kinds of communities where the rioting occurred. Few people seem to seriously consider what all this "junk food" might be doing to our children's brains. Hard evidence is tricky to come by (randomised controlled trials are extremely difficult to conduct in the area of food and diet - especially over the long periods ideally needed), but the evidence we do have is rather worrying.
Sugar has long been suspected of exacerbating - if not causing - some mood and behaviour problems. High intakes of sugar and refined starch (from sugary soft drinks, sweets, cakes, biscuits and other processed foods) rapidly drive up blood glucose levels, unless accompanied by enough dietary fibre, fat or protein. The faster blood glucose rises, the more insulin is released, and so the faster blood glucose falls again. The brain's primary fuel is glucose, so it is easy to see how rapid swings in blood sugar could play havoc with mood, behaviour and cognition (as well as leading in the longer-term to insulin-resistance and Type 2 diabetes). Many studies have found links between antisocial behaviour and poor blood sugar control - but in experimental studies (even if these are not funded by the sugar industry), reliable effects are more difficult to demonstrate. This is because in the short-term, sugary foods and drinks that raise our blood sugar back off the floor will actually enhance mental performance. For anyone interested in the truth about sugar (and particularly fructose) the lecture on YouTube by Professor Robert Lustig from the University of California - a paediatrician specialising in obesity and metabolic syndrome - cannot be recommended highly enough. He does not focus on brains and behaviour per se, but he explains thoroughly (with all the biochemistry) why it is sugar, and not fat, that is driving the obesity epidemic, why not all calories are equal, and why sugar is addictive. And I will simply repeat: diets that are bad for the body are likely to be bad for the brain.
Maternal Diets need improving
One of the most disturbing aspects of how poor diets can affect brains and behaviour concerns "nutritional programming". Early nutrition is now known to affect gene expression, such that the diets mothers consume during pregnancy can have permanent, lifelong effects on the metabolism and future health of their unborn children. Low birth weight (LBW), a clear sign of prenatal malnutrition that has long been linked with adverse child developmental outcomes - both physical and mental. The UK has one of the highest rates of LBW in Europe (at over seven per cent) and it has been increasing rather than decreasing over the last 40 years.
The type of fats in our diets is a particularly serious cause for concern (both prenatally and throughout life). This is even more important for mental health than it is for physical health, because 60 per cent of the brain is fat - and it needs to be the right kind for the brain to develop and function normally. The fats that the brain and nervous system particularly need are the omega-3 and omega-6 long-chain polyunsaturates, and crucially, these also need to be in the right balance. Instead, our modern western-type diets are seriously deficient in omega-3, and provide an excess of omega-6 fats. An unhealthy balance of dietary fats has major implications for mood, behaviour and learning ability. Long-chain omega-3 deficiencies are strongly linked with a very wide range of mental health disorders; and meta-analyses of controlled trials show that the omega-3 found in fish oils can reduce symptoms of both depression4 and ADHD5.
Omega-3 deficiencies during pregnancy have been repeatedly shown in animal models to cause depression and anxiety in the offspring. Very recently, a "nutritional programming" mechanism for this was demonstrated, involving permanent disruption to brain endocannabinoid systems6. The main endocannabinoids (the brain's own cannabis, if you like) are actually derived from the main dietary longchain omega-6 fat, arachidonic acid, although this fact is little known or appreciated. The Journal in which this study was published made an editorial comment, entitled "Neuroscience meets Diet". Yes - since industrialisation, we have dramatically changed our food supply in numerous ways that amount to uncontrolled experiments, with devastating consequences for physical health7. Are we now seeing some of the consequences in our children's behaviour, too?
Vitamin deficiencies are widespread
In the last National Dietary Survey3, deficient intakes of iron, zinc and Vitamin A were found for one in ten children in the UK on average (iron varied more by agegroup - with toddlers and teenage girls most at risk). Each of these nutrients is well known to affect brain function as well as physical health - and both zinc and iron have separately been linked with ADHD in evidence that includes controlled treatment trials. Zinc is also needed for literally hundreds of different enzymes in the brain and body. Like Vitamin A (and Vitamin D - deficiencies of which are another major issue in the UK, especially for darker-skinned individuals), it is crucial to a healthy immune system.
Zinc deficiencies during pregnancy lead to impaired immunity in the offspring, and this also appears to be transmitted to future generations via epigenetic mechanisms. Prenatal Vitamin D deficiencies have permanent effects on the brain and nervous system consistent with an increased risk for both ADHD and schizophrenia. The importance of nutrition in pregnancy extends way beyond folic acid - but in practice, very little is being done to address the implications of this.
There are numerous other ways in which nutrient deficiencies and imbalances can impact on brain development and functioning, but one more point is worth making. Many commentators on the recent UK riots used the words "cretins" or "cretinous" to describe the people involved and their behaviour. Cretinism actually refers to the serious mental and physical retardation produced by iodine deficiency. Even mild iodine deficiencies during pregnancy can knock several points off the IQs of the resulting children8. A recent study of pregnant mothers from Surrey found that all of them were iodine-deficient according to W.H.O. criteria, suggesting that we might do well to enforce the iodisation of salt in this country. That would seem a simple way to reduce just one of the many nutritional risk factors for behavioural and learning disorders in our children.
For anyone still doubting the evidence, consider this. A recent comprehensive survey found that 38 per cent of the European population now has a diagnosable mental health disorder9. It also showed that the cost burden of this epidemic greatly exceeds that of the physical health conditions that already threaten to overwhelm our health services and our economy. According to the authors of this detailed report, "mental and neurological disorders must be considered to be Europe's foremost health care challenge of the 21st century." This challenge cannot be met without putting nutrition and diet at the forefront of public health policy; and the good news is that it would benefit our bodies as well as our brains. The weight of evidence clearly shows the immense costs to society if we continue to ignore how integral a role nutrition plays in all of our lives. But real change has to come from the ground up, involving health visitors, midwives, school nurses and all other health professionals working with families and children. If we want a safer and healthier society, we have no time to lose.
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2. Zaalberg A, Nijman H, Bulten E,et al. Effects of nutritional supplements on aggression, rule-breaking, and psychopathology among young adult prisoners. Aggressive Behavior.Wiley InterScience, 2010;36(2): 117 - 26
3. Gregoryet al. UK National Diet and Nutrition Survey: young people aged 4 to 18 years, 2000, Volume 1: Findings. London: HMSO.
4. Sublette ME, Ellis SP, Geant AL, Mann JJ. Meta-analysis of the effects of eicosapentaenoic acid (EPA) in clinical trials in depression.J Clin Psych2011. Sep 6. (Epub ahead of print)
5. Bloch MH, Qawasmi A. Omega-3 Fatty Acid Supplementation for the Treatment of Children With Attention-Deficit/Hyperactivity Disorder Symptomatology: Systematic Review and Meta-Analysis.J Am Acad Child Adol Psyc, 2011 16 August. (EPub ahead of print)
6. Lafourcade M, Larrieu T, Mato S,et al. Nutritional omega-3 deficiency abolishes endocannabinoidmediated neuronal functions.Nature Neuroscience, 2011;14(3): 345-50. Epub 2011 Jan 30.
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9. H U Wittchen, F Jacobi, J Rehm,et al.The size and burden of mental disorders and other disorders ofthe brain in Europe 2010.European Neuropsychopharmacology, 2011; 21: 655-679.