Environmental neurotoxins in food in a perspective of global health approach

Abstract

The increasing incidence of Autism Spectrum Disorders (ASD) suggests a causal environmental factor. Neuropathological brain changes in autism are consistent with alteration of neuronal cortical migration occurring early in gestation (gestational age 8-12 weeks). Maternal thyroid hormones are critical for neuronal migration. Thyroid function depends on appropriate iodine content in the diet and numerous environmental factors affect thyroid function. A large number of anti-thyroid compounds are present in natural and man-made products and many neuroendocrine disruptors have been identified. The main anti-thyroid compounds and endocrine thyroid disruptors will be reviewed in this presentation (Berbel, Navarro, Roman Front Endocrinol 2014;5:146). Based on clinical and experimental evidence, Román (J Neurol Sci 2007;262:15-26) postulated that maternal hypothyroxinemia (low T4) during the first trimester of gestation may adversely affect neuronal migration leading to abnormal cortical formation of brain and cerebellum resulting in autism. Using the database from a cohort of mothers and their children in “The Generation R Study” in Rotterdam, The Netherlands (Eur J Epidemiol 2006;21:475-84) a total of 9,778 mothers with a delivery date between April 2002 and January 2006 were recruited in the study. The Generation R Study was approved by the Medical Ethical Committee of the Erasmus Medical Center, Rotterdam, and samples for the biobank were obtained (Eur J Epidemiol 2007: 22:917–23). Statistical data analyses were performed to determine the correlation existing between maternal thyroid function during gestation and the incidence of ASD in case-control studies comparing the group of cases (mothers of children with diagnosis of ASD) versus a matched control group (mothers of children without ASD) using gestational age at time of thyroid function tests and results of thyroid function tests (TSH, T3, T4) in the mothers. The incidence of ASD in women with early maternal hypothyroxinemia was found to be higher than in normal controls with increased risk. The effect of neuroendocrine disruptors will be analyzed. We hope these results will help to prevent autism.