Autism and lack of D3 vitamin: A systematic review

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental disorder characterized by social communication deficits and restricted, repetitive patterns of behavior. Several medical conditions including gastrointestinal (GI) problems, asthma and allergies have been associated with ASD, and multiple risk factors, both genetic and environmental, have been proposed. Among them, vitamin D (VD) deficiency is probably associated with ASD, and may play a role in the condition. We conducted a systematic review of the literature for the period January 1, 2010 through June 15, 2014, according to PRISMA guidelines, aiming to investigate the complex biological interplay between VD, metabolism, immune system and nervous system in ASD. Different trends in the association between ASD and VD deficiency have been observed, and factors such as gender, ethnicity, sampling, and methodology play a role in the results and outcomes. At present, for at least a subgroup of ASD individuals, an imbalance in VD metabolism probably exists and may be associated with the condition. In this cohort, VD replacement in these individuals might contribute to improving ASD symptoms and/or associated conditions. This topic is an important challenge for future research, and could lead to a new tailored therapeutic approach for VD in ASD. (C) 2014 Elsevier Ltd. All rights reserved.