Iron is a mineral necessary for most forms of life. In humans it is a constituent of the heme protein found in red blood cells. Heme proteins are used in the transport of oxygen to all tissues of the body as well as for the removal of carbon dioxide, the latter a waste product of cellular metabolism. Iron also catalyzes the formation of so-called reactive oxygen species. These reactive chemical intermediaries engender a cascade of interactions that ultimately end up modifying or destroying the function of biological macromolecules, i.e., proteins, carbohydrates, lipids, and nucleic acids. Whenever there is an imbalance between reactive oxygen species and the body’s ability to neutralize them, cells in the body experience oxidative stress. This deleterious cascade of events may lead to premature cell death, including those found in the brain. Recent research suggests the involvement of oxidative stress and iron metabolism dysregulation in several neurodegenerative disorders including Alzheimer’s, Parkinson’s, amyotrophic lateral sclerosis (ALS) and Huntington’s disease, as well as in a syndromic type of autism.
In the brain, iron is needed for the synthesis of neurotransmitters and for myelin (the insulation of axons) formation. Normal brain development requires the availability of iron in a tightly controlled age- and brain-region-dependent manner. Iron-deficient infants manifest behavioral and cognitive developmental delays. Despite iron supplements, some iron-deficient babies may never recover as manifested in tests of learning, memory and thinking. Even more striking, many of these iron deficient infants may actually get worse as they get older. These cognitive deficits appear to be directly associated to the iron deficiency and not the comorbid anemia.
Recent studies suggest that children with attention-deficit/hyperactivity disorder have low levels of iron in their brains. In animals, iron deficiency has been linked to deficits in spontaneous exploratory activity and anxiety-like behaviors. In both ADHD and animal models, the behaviors appear to be associated to abnormalities of a neurotransmitter known as dopamine. Deficits in the bioavailability of iron often result in alterations in the production and function of dopamine and opiates neurotransmitters.
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Some studies claim that iron deficiency and anemia are common in children with autistic spectrum disorder. Low iron levels when combined with advanced maternal age, is associated with a 5-fold increase for autism. In these cases the level of iron deficiency is not related to the severity of autistic symptoms
You should consider iron deficiency if you are feeling tired and weak, your work or school performance diminishes, experience difficulties in maintaining body temperature, have mood changes, suffer from multiple infections, and/or have an inflamed tongue. Your threshold for investigating this possibility should be lower if you are dealing with a baby that was born prematurely (more than three weeks before term) or has a low birth weight.
Many autistic individuals receive iron supplement as a preventive measure. If not followed carefully these supplements may cause nausea, vomiting, constipation and ulcerations of the gastrointestinal tract. Because of this danger you should keep iron supplements well outside the reach of younger children. Although the body absorbs only 10% of the iron consumed in the diet, it may be best to try and supplement iron, when necessary, through dietary means. Some suggestions to supplement your iron by dietary means include the following: Be aware that iron in meat sources is more easily absorbed than that available in grains and plant foods. Iron absorption may be reduced by antacids, calcium, zinc, magnesium, phytates, soy, nonsteroidal anti-inflammatory agents (may produce bleeds in the GI tract), coffee and tea. Iron rich foods include red meat, dark poultry, tuna, salmon, eggs, tofu, dried fruits and leafy green vegetables.
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References
Herguner S, et al. Ferritin and iron levels in children with autistic disorder. Eur J Pediatr 171(1):143-6, 2012.
Latif A, et al. Iron deficiencyin autism and Asperger syndrome. Autism 6(1):103-114, 2002.
Schmidt RJ, et al. Maternal intake of supplemental iron and risk of autism spectrum disorder. Am J Epidemiol 180(9):890-900, 2014.
Veeravigrom M, et al. Neurodegeneration with brain iron accumulation disorder mimics autism. Pediatr Neurol 51(6):862-3, 2014.