NEW STUDIES SHOW STRONG LINKS BETWEEN DIET, BEHAVIOR

Can the right diet make a child less hyperactive, alleviate an adult's depression, or even reduce aggression and antisocial acts? Recent research offers surprising evidence about the value of nutritional interventions for a wide range of behavioral and mood disorders.

Researchers in the 1970s questioned the connection between diet and behavior. Newer, more sophisticated studies, however, reveal that for many children, the food/behavior link is real.

J. Breakey reviewed studies on food and behavior conducted between 1985 and 1995, and concludes that the results "clearly show a relationship" between what children eat and how they act. "The most important finding," she says, "was that in almost all studies there was a statistically significant change in behavior with dietary intervention." In addition, the studies revealed a continuum of responses to dietary interventions, "rather than the all-or-nothing earlier expectation."

Although diet changes reportedly can improve a wide range of behavior problems, including hyperactivity and sleep problems, Breakey says "an important unexpected finding is the number of researchers who emphasize that the symptom most affected by diet is mood, especially irritability."

While most studies on diet and behavior have focused on reducing hyperactivity, there is evidence that diet also has a strong influence on aggression. Physician Melvyn Werbach cites some examples:

-- One study found that 20 subjects with marginal deficiencies of thiamin were impulsive, highly irritable, aggressive, and sensitive to criticism. After their diets were supplemented with thiamin, the subjects' behavior improved significantly.

-- Research shows that among adolescent males, iron deficiency is directly associated with aggressive behavior. Furthermore, one study found that iron deficiency was nearly twice as prevalent in a group of incarcerated adolescents as among their non- incarcerated peers. Werbach says animal studies indicate that iron deficiency may cause behavioral impairment by diminishing dopamine transmission.

-Studies show that rats fed diets depleted in the amino acid tryptophan become more aggressive toward mice. In addition, research on vervet monkeys found that tryptophan-free diets increased aggression in males, while high-tryptophan food reduced aggression in both males and females.

These findings are not surprising, according to Werbach, because tryptophan is the dietary building block of the brain chemical serotonin, and low levels of this neurotransmitter are strongly linked to behavior problems including impulsive aggression (See related article, Crime Times, 1995, Vol. 1, No. 1-2, Page 7).

While noting that too little scientific research is available on the diet/aggression connection, Werbach concludes, "Epidemiological studies have repeatedly found associations between overaggressive behaviors and deficiencies of several essential nutrients: niacin, pantothenic acid, thiamin, vitamin B6, vitamin C, iron, magnesium and tryptophan." This evidence, he says, "argue[s] that a nutritional approach should be considered in the treatment of the aggressive behavioral syndrome."

Depression, a serious problem in and of itself, is a risk factor for aggression and possibly even for criminal behavior (See related article, Crime Times, 1997, Vol. 3, No. 4, Page 6). Recent research points to a strong link between depression and dietary deficiencies, and in particular deficiencies of the B vitamin folate (folic acid).

Beginning in the 1980s, study after study has shown that low levels of folic acid are correlated with depression. Jonathan E. Alpert and Maurizio Fava recently noted that "depressive symptoms are the most common neuropsychiatric manifestation of folate deficiency," and that as many as one third of adults diagnosed with depressive disorders have deficient or borderline blood levels of folate. Studies by Alpert and Fava, as well as other researchers, also suggest that depressed patients with low folate levels respond poorly to antidepressant treatment, compared to subjects with normal folate levels.

T. M. Ortega and colleagues say that the relationship between depression and low folate levels is easily explained, "because of the role of folates in [the] synthesis of neurotransmitters and elements of neuron structure."

Another nutrient linked strongly to mood is selenium. British researchers David Benton and Richard Cook first reported, in 1991, that in normal subjects, higher selenium intake is "associated with a general elevation of mood and in particular, a decrease in anxiety." The lower the level of selenium in their subjects' diets, Benton and Cook reported, "the more reports of anxiety, depression, and tiredness," all of which decreased following five weeks of selenium supplementation.

Wayne C. Hawkes and Linda Hornbostel recently conducted a similar experiment in the U.S., studying the effects of selenium supplementation or depletion on 11 healthy men. "Adding more selenium to the diets of our. volunteers had no effect on mood," they say, apparently because the U.S. subjects began with higher selenium levels than the British subjects. "However," the researchers say, "we did find that taking most of the selenium out of our volunteers' diets worsened the moods of those volunteers who had been consuming the lowest amounts of selenium prior to the beginning of our study. This was similar to the British study where they found that the moods of the people who ate the least selenium were improved most by giving them more selenium."

Low levels of tryptophan also may lead to depression. In 1997, K. A. Smith et al. studied 15 women who had experienced major depression in the past but were no longer taking antidepressants. The subjects drank either an amino acid mixture containing tryptophan, or the same mixture without the tryptophan, and their depressive symptoms were measured before and seven hours after drinking the substances. "The tryptophan-free mixture produced a 75% reduction in plasma tryptophan concentration," the researchers report. "After drinking [this] mixture, ten of the 15 women experienced temporary but clinically significant depressive symptoms." No mood changes were seen when patients drank the mixture containing tryptophan.

In addition to influencing mood, aggression, and symptoms of hyperactivity, diet appears to significantly improve the IQs of some children (See related article, Crime Times, 1996, Vol. 2, No. 2, Page 4). Since hyperactivity, hyperaggressiveness, depression, and IQ all are associated with criminality, some researchers are investigating whether or not diet may be useful in treating criminals (and, in particular, young delinquents). To date the research, while sparse, is encouraging.

During the early 1980s, Stephen Shoenthaler instituted dietary changes in a dozen juvenile correctional institutions. His data showed that following these dietary interventions, which involved 8076 delinquents, the institutions had a 47% reduction in antisocial behavior including assaults, insubordination, horseplay, suicide attempts, and general rule violations. Schoenthaler notes, additionally, that "the more violent the bad behavior [before dietary interventions began], the more the improvement."

In a typical study, Schoenthaler supplemented the diets of 71 residents of a state juvenile treatment facility. During the treatment phase of the double-blind, placebo-controlled, crossover study, Schoenthaler reported, "overall violence fell 66 percent from 306 incidents to 104. Total AWOL and escape attempts fell 84 percent from 79 to 13 incidents and destruction or theft of state property dropped 51 percent from 49 to 24 incidents." He concludes that "the trial demonstrated, rather convincingly, that supplementation at dose levels which pose no risk whatsoever can produce a significant reduction in violence and antisocial behavior in incarcerated juveniles."

Preliminary results from current studies by Schoenthaler corroborate these earlier findings.

Researchers investigating dietary interventions for behavior- disordered children, troubled teens, and antisocial adults are excited about the accumulating evidence showing that these simple measures may have profound impact, but they are also frustrated by a lack of interest on the part of most clinicians.

"Unfortunately, the idea that disturbed behavior and crime in particular are essentially the result of adverse social factors is so deeply embedded in human society that those seeking to conduct studies of non-social factors such as defective diets usually find that they face an uphill task," researcher Derek Bryce-Smith recently commented. "The demonstrated links between diet and behavior badly need to be extended as a matter of urgency, and their importance recognized."

"The role of diet and behaviour in childhood," J. Breakey, Journal of Paediatr. Child Health, 33, 1997, pp. 190-194. Address: J. Breakey, P.O. Box 8, Beachmere, QLD 4510, Australia.

"Nutritional influences on aggressive behavior," Melvyn R. Werbach, Journal of Orthomolecular Medicine, Vol. 7, No. 1, 1995. Address not listed.

"Nutrition and depression: the role of folate," Jonathan E. Alpert and Maurizio Fava, Nutrition Review, May 1997, Vol. 55, No. 5, pp. 145-149. Correspondence: Maurizio Fava, fax 1-617-726- 7541.

"The role of folates in the diverse biochemical processes that control mental function," T. M. Ortega, P. Andres, A. Lopez- Sobaler, A. Ortega, R. Redondo, A. Jimenez, and L. M. Jimenez, Nutr Hosp, Vol. 9, No. 4, July 1994, pp. 251-256. Address not listed.

"Effects of dietary selenium on mood in healthy men living in a metabolic research unit," W. C. Hawkes and L. Hornbostel, Biological Psychiatry, Vol. 39, No. 2, January 15, 1996, pp. 121-128. Address not listed.

"The impact of selenium supplementation on mood," David Benton and Richard Cook, Biological Psychiatry, Vol. 29, No. 11, June 1, 1991, pp. 1092-1098. Address not listed.

"Relapse of depression after rapid depletion of tryptophan," K. A. Smith, C. G. Fairburn, and P.J. Cowen, The Lancet, Vol. 349, No. 9056, March 29, 1997, pp. 915-919. Address not listed.

"Abstracts of early papers on the effects of vitamin and mineral supplementation on I.Q. and behaviour," Stephen J. Schoenthaler, Personal and Individual Differences, Vol. 12, No. 4, 1991, pp. 335-341. (Additional information from personal communication.)

"Crime and nourishment," Derek Bryce-Smith, Perspectives, March 15, 1996. Address not listed.

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