This chapter reviews the literature surrounding autism spectrum disorders (ASD) and their relation to gastrointestinal (GI), behavioral, neurological, and immunological functioning. Individuals with ASDs often have poor GI health, including bowel motility issues, autoimmune and/or other adverse responses to certain foods, and lack of necessary nutrient absorption. These issues may be caused or exacerbated by restrictive behavioral patterns (e.g., preference for sweet and salty foods and/or refusal of healthy foods). Those individuals with GI issues tend to demonstrate more behavioral deficits (e.g., irritability, agitation, hyperactivity) and also tend to have an imbalance in overall gut microbiome composition, thus corroborating several studies that have implicated brain—gutpathways [sic] as potential mediators of behavioral dysfunction. We examine the literature with regard to dietary approaches for ASD treatment, including elimination diets of either gluten or casein, complex carbohydrates, a ketogenic diet, and a low oxalate diet. We also explore the research examining dietary supplements such as fatty acids, pro- and prebiotics, vitamins, minerals, glutathione, phytochemicals, and hormones. The research on dietary approaches to treating ASDs is limited and the results are mixed. However, a few approaches, such as the gluten-free/casein-free diet, fatty acid supplementation, and pre/probiotics have generally demonstrated improved GI and behavioral symptoms. Given that GI issues seem to be over-represented in ASD populations, and that GI issues have been associated with a number [sic] behavioral and neurological deficits, dietary manipulation may offer a cheap and easily-implemented approach to improve the lives of those with ASDs.

Keywords: neurodevelopment, neurological disorders, gastrointestinal dysfunction, eating behaviors, gut-brain axis, nutraceuticals

LLU Discipline





School of Behavioral Health

First Advisor

Richard E. Hartman

Second Advisor

Cameron L. Neece

Degree Name

Doctor of Psychology (PsyD)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Autism spectrum disorder; Exclusion diets; GASTROINTESTINAL diseases; NEURAL development


Doctoral Project

Page Count

vii; 44 p.

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives