Mercury exposure, nutritional deficiencies and metabolic disruptions may affect learning in children
"Children with Autism Spectrum Disorders have increased body burdens of mercury . Because mercury inhibits cysteine ligands in the metal clearing metallothionein (MT) proteins that normally bind with metal ions such as copper and zinc , consumption of mercury-contaminated HFCS and other zinc depleting substances [10,11] over time by sensitive individuals may induce an MT malfunction (Figure (Figure1).1). Such a malfunction may lead to in membranes leading to lipid peroxidation and cell damage  (Figure (Figure1).1). Exposure of the brain to excessive oxidative stress may lead to a loss in learning capacity (Figure (Figure1).1). Many children with ADHD are deficient in the micronutrient zinc [69,70]. Consumption of zinc depleting food additives [9-11] increases hyperactive behaviors (inattention, impulsivity, and over activity) both in children with extreme hyperactivity (i.e., ADHD) and in the general population . Increased hyperactivity is associated with the development of educational difficulties especially in reading . In rats, zinc deficiency along with oxidative stress predisposes the brain to damage by disruption of the blood-brain barrier  and prenatal zinc deficiency has pronounced effects on postnatal metallothionein metabolism, which can persist into adulthood ."