Autism Health and Nutrition

Kelly Barnhill, MBA, CN, CCN, discusses nutrition in autism based on recent publications. She outlines research updates on amino acid patterns, probiotics, and dietary interventions, underscoring both what we know and what we don’t know. The speaker discusses the clinical interpretation and application of this research, touching on common nutrient deficiencies before the Q&A.

In this webinar:

0:00 – Introductions
2:00 – Prospective study on amino acid patterns
5:50 – Prospective Study on Probiotic Intervention
7:40 – Systematic Review of Dietary Intervention and Gut Health
10:54 – Bibliometric Analysis of Influential Articles
13:47 – Systematic Review of Probiotics in Autism
16:06 – Nutrition Reviews Study on Mediterranean Diet
19:28 – Study on Gluten- and Casein- Free Diet
21:48 – Review on Ketogenic Diet
26:16 – Food, Nutrition, and Autism
27:57 – Systematic Review – Food as Medicine
34:40 – Clinical interpretation and application
40:30 – Micronutrients
44:10 – Q&A

Prospective Study on Amino Acid Patterns 

Dr. Barnhill outlines a 2025 study on amino acid patterns in over 1,200 children (2-8 years) with autism. Researchers found lower levels of glutamine in children with autism and significant differences in several amino acids across groups (2:00). Specifically, the study noted that those with neurological impairment were deficient in amino acids that presented with susceptibility to neurocytotoxicity and oxidative stress, while those with nutritional concerns presented with a different set of issues, pointing more toward metabolic concerns. Barnhill explains that these findings substantiate clinical observations and suggest that specific amino acid imbalances may be related to different manifestations of autism, supporting the use of nutritional therapeutic intervention to balance amino acid levels. The speaker emphasizes that this is the only amino acid study presented in a prospective way that has been published in a reputable journal in the past few years. 

Amino Acid Patterns in Children with Autistic Spectrum Disorder: A Preliminary Biochemical Evaluation (Ferraro et al., 2025)

Prospective Study on Probiotic Intervention 

The presenter outlines another recent study that speaks to the concerns of effects of probiotic support for children with autism, AD/HD, and children with both diagnoses (AuDHD) (5:50). Children were given a probiotic or a placebo for three months. Researchers saw a significant improvement in hyperactivity and impulsivity in both the autism and ADHD groups. Most notably, the “comfort score” on a quality-of-life instrument showed significant improvement for autistic children. Barnhill notes that, although this is a small study, its findings support clinical observations that probiotics can improve gastrointestinal symptoms and other related issues in children with autism, potentially impacting their quality of life.

Effect of Probiotics on the Symptomatology of Autism Spectrum Disorder and/or Attention Deficit/Hyperactivity Disorder in Children and Adolescents: Pilot Study (Rojo-Marticella et al., 2025)

Systematic Review of Dietary Intervention and Gut Health 

Barnhill examines a systematic narrative review of all articles published between 2000 and 2024 related to autism, dietary interventions, probiotics, and the microbiome. (25-year review) (7:40). The review validated that dietary intervention can improve GI symptoms and gut health for children with autism, which in turn improves their quality of life. Researchers also identified a cycle where sensory processing issues lead to food avoidance (ARFID), which decreases microbiome diversity and increases harmful microbial species, leading to a neuroinflammatory process that affects behavior (9:12). The speaker asserts that this review provides a strong rationale for addressing GI and microbiome concerns as part of a comprehensive care plan for individuals with autism.

Unraveling the Connections: Eating Issues, Microbiome, and Gastrointestinal Symptoms in Autism Spectrum Disorder (Tomaszek et al., 2025)

Bibliometric Analysis of Influential Articles 

The speaker highlights another 25-year study that reviewed all publications on microbiome treatment in autism since 2000 to identify the most impactful and cited articles (10:54). This is one of the first in a series of bibliometric analyses. The study identified two landmark publications: a 2013 mouse model study that established the link between the gut microbiome and ASD, and a very early, relatively small study from 25 years ago that showed improvements in both GI symptoms and behavior in a small group of autistic children treated with an oral antibiotic. These two studies, along with many more, laid the groundwork for the growing field of gut-brain research in autism and further validated the clinical utility of targeting gut health.

Influential articles in autism and gut microbiota: bibliometric profile and research trends (Ying et al., 2025)

Systematic Review of Probiotics in Autism 

Barnhill discusses a systematic review that analyzed 10 completed and published clinical studies, as well as 18 ongoing clinical trials, on the use of probiotics in autism. (13:47). Reviewers found that probiotics can improve social behaviors, drastically improve GI symptoms, and positively alter the gut microbiome when used appropriately. The presenter emphasizes this paper as a valuable and easily accessible resource for clinicians and parents, as it provides research backing for the use of probiotics in addressing a range of symptoms beyond just GI issues – essentially describing what we’ve learned and why it’s important.

Probiotics in autism spectrum disorders: a systematic review of clinical studies and future directions  (Barba-Vila et al., 2025)

Nutrition Reviews Study on Mediterranean Diet

Barnhill notes that we are seeing more and more solid research emerging about how dietary intervention benefits individuals across the board, highlighting that there is no one-size-fits-all approach for any of us and what that means for clinical applications. She outlines a 2025 evaluation of all studies on children (6-16 years) with autism and ADHD, examining responses to nutritional interventions (16:06). The paper concluded that 70% of individuals who followed a Mediterranean diet showed significant improvement in ADHD symptoms. It also noted significant improvements in depression (80%) and anxiety (50%). The speaker states that these results suggest that focusing on a whole, unprocessed Mediterranean-style diet can be a profound and effective intervention for improving neurological and mental health symptoms. 

Mediterranean Diet and Mental Health in Children and Adolescents: A Systematic Review (Camprodon-Boadas et al., 2025)

Study on Gluten- and Casein-Free Diet

The speaker outlines another 2025 study that evaluated a 12-week trial involving 80 children (4-10 years), using a strict, prescribed gluten- and casein-free diet in combination with and separate and distinct from a neurodevelopmental physical therapy program (19:28). Barnhill notes that families prepared meals on their own, meaning there was no technical control group. Researchers saw significant gains in gross motor skills and cognitive function only when the diet was combined with the therapy program. The dietary group alone showed no significant changes. This study suggests that a multidisciplinary, holistic approach is key, and that dietary interventions may be more effective when combined with other therapies.

Effect of Therapeutic Diet Along with Special Physiotherapy Program on Gross Motor Development and Cognitive Function in Autistic Children: A Randomized Controlled Trial (Alsayegh et al., 2025)

Review on Ketogenic Diet

A review of all published papers on the ketogenic diet for individuals with autism found that the diet is not appropriate for everyone due to the high heterogeneity of autism. However, Barnhill continues, it does hold great potential for some individuals by reducing bacterial dysbiosis, decreasing pro-inflammatory cytokines, enhancing gut health, and providing a neuroprotective effect via ketone bodies (21:48). Barnhill underscores that while the ketogenic diet can be effective for the right patient, it should only be implemented with professional guidance due to its complexity and potential dangers when applied inappropriately. More research is needed.

Exploring the potential of the ketogenic diet in autism spectrum disorder: metabolic, genetic, and therapeutic insights (Schrickel et al., 2025)

Food, Nutrition, and Autism

The presenter provides a summary article describing our current understanding of nutrition and autism from a societal and cultural perspective. The paper tangentially addresses all the issues that people in the US should be aware of and attuned to, including environmental and food exposures from prenatal to childhood. Barnhill asserts this study is foundational for building an appropriate dietary approach and understanding what barriers might exist (26:16). 

Food, nutrition, and autism: from soil to fork (Shepard et al., 2024) 

Systematic Review – Food as Medicine

The speaker notes a recent systematic review that addresses the use of dietary intervention and therapeutic nutritional support across various diagnoses (27:57). The authors highlight several publications that support the idea that food can be considered a form of medicine and is increasingly understood as a pharmaceutical component in health and medical diagnoses. Barnhill emphasizes the importance of not viewing food choices and dietary recommendations for autism as “other” to the general population’s nutritional understanding. Culturally, we continue to recognize that our diets are integral to health and need to be taken seriously. She states that “we need to hold autism research and interventions to the same standards.” This study ultimately resolidifies the interconnectedness of the gut and brain by highlighting the impact of microbiome health in the GI system on both the vagal nerve and cognition (31:00). 

Nutraceuticals in Psychiatric Disorders: A Systematic Review (Bozzatello et al., 2024)

Clinical interpretation and application

According to the presented information, Barnhill asserts that clinicians should assume that diet matters and that a nutritionist or dietary specialist should be included in care counseling and planning for children and adults with autism (34:40). She underscores the importance of avoiding packaged food products, ensuring fiber and water intake are sufficient, and addressing feeding concerns with care and compassion. She also suggests incorporating family and community into diet changes, meal preparation, and eating habits. The speaker also suggests working with a professional to outline any specialized diets (37:40). 

Micronutrients & Therapeutic Support

Barnhill lists common micronutrient deficiencies, including B vitamins, fat-soluble A and D, and Omega-3 fatty acids. She notes that addressing gaps with supplemental support is reasonable and appropriate to meet the minimal needs in the case that someone doesn’t have access to those nutrients via diet (40:30). She cautions viewers about the supplement market, noting that it is not regulated; and suggests consulting with someone well-versed in what’s needed and the efficacy of different brands before the Q&A (44:10).