Certain Nutritional Interventions May Be Effective in Reducing Childhood/Youth Aggressive and Antisocial Behavior as Well as Criminal Offending
The Review in Brief
Nutritional interventions targeting a large number of nutrients (e.g., general improvement in diet or provision of food supplements with a wide array of vitamins and minerals) may be effective in reducing aggression (small effect), antisocial behavior (moderate effect), and offending (large effect). Omega-3 fatty acid supplementation has a small effect in reducing both aggression and antisocial behavior. Vitamin D supplementation has a moderate effect in reducing antisocial behaviors.
What Is This Review About?
Aggressive or antisocial behaviors in children and young people can cause problems at home, with friends, at school, as well as in other settings, and may lead to long-term challenges for both the individual and society. Researchers are exploring whether changes in nutrition might help reduce these behaviors. A nutritional intervention refers to any action taken to improve the availability of nutrients in the body, and it can involve three main approaches: (1) making changes in what foods a person regularly eats, like eating more vitamin D-rich foods; (2) fortifying common foods by adding extra nutrients, like drinking milk with added vitamin D; and (3) taking supplements, which are pills or other products that provide specific (group of) nutrients, like a multivitamin supplement. This review looked at whether any nutritional changes could help reduce aggression, antisocial behaviors (like theft, vandalism, or other misbehavior), or crimes in children and young adults.
What Is the Aim of This Review?
This Campbell systematic review examines the effects of nutritional changes on aggression, antisocial, or criminal behaviors in children and young adults (up to the age of 24). This article summarizes previously collected data from 50 individual studies completed by other researchers.
What Are the Main Findings of This Review?
What Studies Are Included?
All 50 studies compared an intervention group and a control group (participants not getting the active nutritional intervention). The studies spanned the period from 1978 to 2023 and were mostly carried out in the United States, Europe, and Asia. Sixteen percent of the studies were conducted on an exclusively male sample, while 82% were conducted on mixed samples of males and females, but the average proportion of males across all studies was quite high (79%). The number of studies on offending and using vitamin D supplementation was quite low; therefore, the results regarding these are much more uncertain.
Do Nutritional Changes Help Reduce Aggression, Antisocial Behaviors, and Offending?
Nutritional interventions targeting a large number of nutrients are effective in reducing aggression (7 studies, small effect), antisocial behavior (13 studies, moderate effect), and offending (2 studies, large effect). For all three outcomes, diet change was considerably more effective than supplementation. Omega-3 fatty acid supplementation has a small effect in reducing both aggression (9 studies) and antisocial behavior (21 studies). Vitamin D supplementation has a moderately large effect in reducing antisocial behaviors (4 studies). Eliminating studies with lower methodological quality decreases intervention effectiveness in some cases (broad-range nutritional interventions for aggression and antisocial behavior, omega-3 fatty acid or vitamin D supplementation for antisocial behavior), while it does not result in considerable changes regarding others (broad-range nutritional interventions for offending, omega-3 fatty acid supplementation for aggression). The data also suggest that the results may not be consistent across different populations or interventions. This means that in future research or implementation efforts, nutritional interventions in certain populations will not be effective in reducing aggression, antisocial behaviors, or offending. While there are several studies on nutritional interventions other than those mentioned above, all seven of them are examined in a single study only, thus not allowing any conclusions beyond those of the original authors.
How Has This Intervention Worked?
Some of the studies found that the increased nutrient levels in participants’ blood were associated with the improvement in behavior, which provides support for the assumption that a good nutrient supply in the body supports a better functioning of the nervous system, which in turn leads to better adaptation to the social environment (less antisocial behaviors).
This review also describes a large number of factors that can support or hinder the successful use of nutritional interventions (e.g., support vs. resistance from family members regarding dietary changes, costs vs. health insurance coverage for food supplements, etc.).
What Do the Findings of This Review Mean?
The results of this review should not be considered complete or definitive. Instead, they should be seen as one of the preliminary attempts to characterize a new research– and clinical field (i.e., nutritional-behavioral sciences) still in its infancy. While many further questions remain to be answered regarding the effectiveness of nutritional interventions in reducing aggression/antisocial behavior/offending, these interventions are safe, relatively easy-to-implement, and cheap. Given that better nutrition not only has the potential to reduce antisocial behaviors but is the basis for both physical and mental health in general, investment in nutritional interventions on all levels of society seems warranted.
More research is needed in more similar samples and using more similar nutritional approaches (e.g., several studies investigating the effects of the Mediterranean diet in young adult offenders) so clearer conclusions can be drawn on who and what type of nutritional interventions are effective in reducing aggressive and antisocial behaviors or criminal offending.
How Up-to-Date Is This Review?
The review authors searched for studies up to February 26, 2024.