stroke; cancer; cognition problems; and a number of behavioral problems, including attention deficit disorders, depression, autism, and suicide.

A number of randomized trials of omega-3 supplementation for mothers during gestation or for infants indicate benefits for cognitive and motor skills, including language development. These improvements could serve as protective factors for MEB disorders. Trials of the effects of omega-3 supplementation on aggression have also been conducted. Studies involving children have had mixed results, with three studies demonstrating a reduction in some symptoms of ADHD and related problem behaviors (Richardson and Montgomery, 2005; Richardson and Puri, 2002; Sinn and Bryan; 2007); one showing a reduction in hostility and aggression, primarily among girls (Itomura, Hamazaki, et al., 2005); two showing no effect on aggressive or disruptive behavior (Hirayama, Hamazaki, and Terasawa, 2004; Voigt, Llorente, et al., 2001); and one finding only limited effectiveness (Stevens, Zhang, et al., 2003). While not yet conclusive, however, the available evidence warrants well-designed experimental trials of the impact of omega-3 in preventing depression and behavioral disorders involving aggression.

The majority of randomized controlled trials of omega-3 supplementation have focused on its use to treat adults with mental disorders. Although two recent meta-analyses report evidence for the potential value of omega-3 supplementation, particularly for depression (Freeman, Hibbeln, et al., 2006; Lin and Su, 2007), another suggests that the effects are negligible (Appleton, Hayward, et al., 2006). All concur, however, regarding the troublesome variability of results; the heterogeneity and poor quality of many studies; and the need for large-scale, well-designed and -executed studies to permit conclusive statements.

Other associations between dietary content and MEB disorders are focused on the potential effects of allergenic foods and large boluses of sugar on the occurrence of ADHD (Wolraich, 1998). More study in this area is warranted.

Neurotoxins

Exposure to neurotoxins, such as lead and mercury, is a significant risk during gestation (see Chapter 5). Postnatal exposures are also of concern. Blood levels of neurotoxins in childhood are correlated with cognitive deficits and MEB disorders, including ADHD and conduct disorder (Braun, Kahn, et al., 2006; Braun, Froehlich, et al., 2008). Evidence has accumulated that blood lead levels once thought to be safe (>10 mg/ml) can be detrimental to infants (Canfield, Henderson, et al., 2003). Protection against exposure to lead, as well as other potential neurotoxins whose effects are not as well documented, is deserving of greater national atten-



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