As well as considering the overall quality of your child's diet and the role of potential allergens, you should look at nutritional deficiencies in specific areas.
Besides B6, supplementation with other B vitamins like niacin and thiamine may, and help, although some children who benefit from B6 are worse on niacin, and vice versa (J learn Disabil. 15:258, 1982), and some may require both. In one study, 33 children with disturbed behaviour were placed on nicotinamide (a derivative of niacin) and then placed on placebo. Only one of the 33 failed to respond to B3 therapy and all relapsed to former behavioural problems 30 days after the placebo was substituted, and recovered again on B3 (Schizophrenia 3:107-113, 1971).A calcium deficiency. One 9 year old was diagnosed as hyperactive and put on drugs for two years. A laboratory study found very low blood calcium level. Simply increasing his intake of milk caused his blood calcium to return to normal and resulted in behavioural improvement within two months, enabling him to stop medication (J learn Disabil. 8:354, 1975). (Note: the solution to low calcium levels need not be milk, which is one of the most common food allergens in children.)
Iron deficiency, which can cause irritability and poor attention. According to one study (Amer J Clin Nutr 33:86-188, 1980) iron deficiency is the most common nutritional deficiency affecting American children (Prog. Hematol. 14:23-53, 1986).
Magnesium deficiency, which is characterized by fidgeting, anxious restlessness, psychomotor instability and learning difficulties among children with a normal IQ (Magnesium in Health and Disease, NY, Spectrum Publications, 1980).
A reduced zinc level. One study found that 20 hyperactive boys had lower levels of zinc in urine, blood, hair and fingernails than a matched set of controls, even though there was no difference in saliva zinc levels again suggesting that in hyperactive children, less zinc is retained in the body (J Nutr Med 1:51-57, 1990).
A deficiency of essential fatty acids. One observational study (Med Hypotheses 7:673-9, 1981) of a large number of hyperactive children supports the hypothesis that many such children have a deficiency of EFAs; five children receiving evening primrose oil considerably improved. Two other studies, however, failed to show that giving hyperactive children evening primrose oil made a difference. This may be because the EFA problem is complicated. Evening primrose oil is rich in omega-6 EFAs, but some children may be deficient in omega-3 EFAs, found in fish, linseed and walnut oils. Giving this type of child evening primrose oil may actually make the problem worse. Determining your child's needs requires some detective work, says nutritional expert Dr Leo Galland. First give your child a tablespoon of linseed oil (or two tablespoons of walnut oil or a teaspoon of cod liver oil). After a month, your child should be less thirsty and her skin and hair smoother and silkier if the deficiency is of omega-3. But if your child exhibits greater thirst, suspect an omega-6 EFA deficiency and give your child two to three 500 mg evening primrose oil capsules a day. Look for improvements in behavioural problems in a month.
An abnormal copper level. Laboratory tests have demonstrated that raised copper levels inhibit the enzyme necessary for the production of serotonin.
Excessive levels of heavy metals like aluminium and lead. Children suffering from hyperactivity or learning disorders have been found to have elevated blood aluminium levels (J Child Psychol Psychiatry (30(4): 515-28, 1989) or blood or hair lead levels (Arch Gen Psychiatry 40:P827-33, 1983).
Excessive phosphate intake, from processed and canned foods. A study of hospitalized hyperaggressive children linked phosphate intake with aggressive behaviour (Hafter, Hertha, Phosphates in Food as a cause of Behavioural Disturbances in Teenage Delinquents. Heidelberg, kriminalistik Verlag, 1979).