Autism spectrum disorders are characterized by difficulties with reciprocal social interactions and restricted patterns of behavior and interest; one of these characteristic behaviors is food selectivity. The objective of this study was to perform a systematic review of the literature published between 1970 and 2013 concerning this eating behavior. The articles identified were analyzed in terms of sample size, study design, and criteria for assessment and intervention, as well as the results, level of evidence and grade of recommendation. The main search was conducted in Medline, Cochrane Library, Scielo, ScienceDirect, and Embase). There is empirical evidence and an overall scientific consensus supporting an association between food selectivity and autism spectrum disorders.

In autism spectrum disorders, many parents resort to alternative treatments and these are generally perceived as risk free. Among these, the most commonly used is the gluten-free, casein-free diet. The objective of this work was to conduct a systematic review of studies published from 1970 to date related to the gluten-free, casein-free diet in autism spectrum disorder patients. Few studies can be regarded as providing sound scientific evidence since they were blinded randomized controlled trials, and even these were based on small sample sizes, reducing their validity. We observed that the evidence on this topic is currently limited and weak. We recommend that it should be only used after the diagnosis of an intolerance or allergy to foods containing the allergens excluded in gluten-free, casein-free diets. Future research should be based on this type of design, but with larger sample sizes.

Sex hormones closely regulate development of the male genital organs during fetal life. The hypothesis that xenobiotics may disrupt endogenous hormonal signalling has received considerable scientific attention, but human evidence is scarce.