Title: How Nutrition Can Affect Behaviour

Key words: behavioural changes, refined carbohydrates, sucrose, antisocial behaviour, malnutrition, food allergies, hyperactivity, antisocial, criminal, food additives, phosphates, monosodium glutamate, vitamins, tobacco, caffeine, addiction, thiamin, folic acid, niacin, pyridoxin, Vit C, riboflavin, lead, cadmium, zinc, copper, cobalt, violent behaviour, hypoglycaemia, drugs, dependence, nutritional therapy,

Date: April 2001

Category: The Mind

Type: Article

Author: Peter Bennett


How Nutrition Can Affect Behaviour


Nutrition can affect behaviour in a number of ways, but the mechanisms involved are not fully understood. Divisions between nutritional factors and behavioural expressions are arbitrary and an individual is likely to be affected by a combination of factors.

Refined Carbohydrates

A number of foods have been associated with behavioural changes, but refined carbohydrates, including sucrose, attract most attention. In corrective institutions for juveniles, Schoenthaler1 reduced sucrose content in diets of delinquents and discovered reductions in antisocial behaviour of 21%, 44%, 48% and 54% of former disruptive behaviours. He argues for dietary controls to effect behaviour and to eliminate malnutrition in children. It is not so much a question of which particular food causes misbehaviour, more a question of whether the range of foods consumed by an individual is properly nourishing for him or her.

Food allergy

It is unlikely that any one food is responsible for anti-social behaviour, bearing in mind the genetotrophic principle (see Nutrition and Behaviour Research). However, there is considerable evidence that specific foods will provoke specific reactions in specific individuals and specific circumstances.

The circumstances depend on the nature of environmental stressors affecting the individual. Reactions may indicate clinical conditions, which become further stressors. This is the problem with food allergies. They are synergistic and may be cause or effect – or both. Contrary to popular opinion, allergies are not directly affective of somatic organs such as the lungs in asthmatics or the skin in those who suffer eczema. Allergens directly affect the brain and the central nervous system. Through the brain they interfere with hormonal and other biochemical processes. There is now an abundance of evidence in the literature by clinical ecologists and clinical psychologists of the role of allergens and their links to hyperactivity in antisocial and criminal behaviour patterns.

Food Additives

Since Ben Feingold suggested that food additives were a possible factor in hyperactivity there have been numerous studies to investigate their effects on behaviour. Many, if not most, have been too poorly designed for them to be taken seriously. One sophisticated double blind, cross over study carried out in Great Ormond Street Hospital for Sick Children demonstrated how research could be successfully carried out in this area, but it only considered two additives out of thousands that are in use by the food industry. The attempts to test Feingold’s hypothesis are fraught with difficulties because of the extent to which food additives are used and the formidable task of separating out the synergistic effects. Phosphates have been particularly linked with problem behaviour3. Adverse effects from mono-sodium glutamate have also been studied.


Poor diet, aggravated by tobacco and caffeine addiction, creates thiamin deficiency with symptoms that include fearfulness, apathy, sensitivity to criticism, aggression, quick anger, hostility and irritability. In a study of 20 functionally neurotic patients aged 13 to 45 showing thiamin deficiency, Lonsdale and Shamberger reported that after treatment, the deficiency symptoms disappeared.

Folic acid is linked with an absence of fear of social consequences. It works with cobalamin and is the most common vitamin deficiency causing poor memory.

People deficient in niacin (vitamin B3) display fearfulness and may act immorally or criminally. Lesser relates examples where criminals with niacin deficiency have an impaired capacity to discern right from wrong.

Pyridoxine (B6) deficiency also produces fear symptoms and is associated with hypoglycaemia. Lesser describes B6 deficiency as causing "epileptic-like nervous symptoms and hysterical, explosive, labile, ‘emotionally upset’ depression".

Vitamin C deficiency reduces capacity to excrete toxins such as lead and cadmium which are neurotoxins.

Riboflavin (B2) deficiency is linked with depression, hysteria, hypomania, hypochondriasis and psychopathic deviation. After 39 days on a B2 deficient diet, normal males showed behavioural changes.


Lead is a highly toxic mineral which has been found to increase abnormal behaviour including hyperactivity and learning difficulties and to reduce intelligence. A study of 2146 children in Massachusetts found that those with high lead toxicity were significantly poorer on measures of distractibility, persistence, independence, impulsiveness, frustration, daydreaming and ability to follow directions needleman 1979. Other studies have given similar results.

The San Luis Obispo County Probation Department found in a study of 20 juvenile delinquents that 70% were learning disabled and 60% had high lead levels3. Cadmium is linked to intellectual performance and Lester et al lester et al 1986 found a direct correlation between the proportion of refined carbohydrates ingested by 184 children and the amount of cadmium in their hair. This is not surprising since zinc and cadmium have similar chemical structures. In the refining of grains such as wheat, zinc is processed out, leaving cadmium. If grains are left whole the zinc is absorbed into the body and the cadmium is excreted. Cigarette smoking is also a major source of cadmium.

Zinc is now widely recognised as a major deficiency in the British and American diets. It is necessary for many processes in the body, including insulin production (which may affect a hypoglycaemic condition), hormonal secretions, neurotransmission, and sexual and emotional maturity. Deficiency symptoms include temper tantrums, photophobia and mood changes. Copper is essential to the body, but in excess can cause severe physical and mental illness. High levels may be related to zinc deficiency, and are linked to some schizophrenias and aggression in children. Iron deficiency, which may result from a zinc imbalance, is associated with faulty perceptual cue processing, conduct problems and learning impairment.

A problem with many of the studies lies in differentiating the precise effects of individual minerals, which can affect each other. A number of researchers have examined mineral profiles with Walsh completing an important study. A group of violent and non-violent male repeater criminals was compared with a group of law-abiding siblings. The non-violent criminals were high in sodium, potassium, cadmium, lead, calcium and magnesium, and low in copper, cobalt and lithium. The violent criminals were high in copper, cadmium, lead, calcium and magnesium, and low in zinc, sodium, potassium, lithium and cobalt. Little is known about the role of cobalt in the body, other than being an essential associate of vitamin B12, but one study by Pihlpihl 1982 also indicated a correlation between cobalt and violent behavioural history.


Hypoglycaemia is quite common and should be considered as a contributory factor in mal-adaptive and criminal behaviourvirkunnen&Hutten 1982. There are however problems in defining hypoglycaemia and designing studies well to monitor its effects and implications. The condition is generally related to a high intake of refined carbohydrates, although blood sugar can drop for many reasons, including for example an allergy to tobacco smoke.

Virkunnen however has compared both offenders and normal controls, and found that violent and impulsive male criminals did test positive for reactive hypoglycaemia. Comparison of these results with glucose tests on non-offending control subjects revealed a positive correlation with aggressive tendencies under the influence of alcohol and with loss of memory or with violent / impulsive acts. He suggests that hypoglycaemia is related to criminal, habitually violent and impulsive behaviour.


Drug-nutrient interactions can have several effects, including:

  1. Changes in food intake.
  2. Impaired nutrient absorption.
  3. Hyper-excretion of nutrients.
  4. Intra/extra cellular nutrient redistribution.
  5. Decreased nutrient requirement.

Prescribed drugs, street drugs, alcohol, caffeine and smoking must all be considered to have adverse physiological effects, even if there are some perceived or actual psychological effects of temporary nature. Addiction research has focused not only on how nutritional conditions can cause or contribute to drug abuse, but also how nutritional therapy can help wean addicts off drug dependenceguenther, 1983, Williams 1979.


There are a variety of ways in which nutrition can and does affect behaviour. This has a multitude of implications in the study and prevention of criminal behaviour, which need further study in order to be fully understood and appreciated.



  1. Schoenthaler, S.J. Nutrient levels and antisocial behaviour in juvenile institutions. Am. Soc. Criminology Meeting. San Diego. November 16th, 1985.
  2. Egger, J. et al. Trial of oligoantigenic treatment in hyperkinetic syndrome. Lancet 1, 1985; 540-545.
  3. Schauss, A.G. Diet, crime and delinquency. Berkeley, Parker House. 1981.


Needleman, H.L., Gunnde, C., Leviton, A., Reed, R. et al. Deficits in psychologic classroom performance of children with elevated lead levels. New Eng. J. Med. 1976; 300, 689-696.

Lester, M.L. et al. Protective effects of zinc and calcium against heavy metal impairment of children’s cognitive function. 1986.

Pihl, R.O. Hair element levels of violent criminals. Can. J. Psychol, 27(6), 1982; 533-534.

Virkunnen, M. & Huttunen, M.O. Evidence for abnormal glucose tolerance test among violent offenders. Neuropsychobiology. 8, 1982; 30-34.

Guenther, R.M. The role of nutritional therapy in alcoholism. Int. J. Biosocial Research. 4(1), 1983; 5-18.

Williams, R.J. Biochemical Individuality. University of Texas Press. Austin. 1979.