Kelly Barnhill, MBA, CN, CCN, summarizes emerging research on nutritional approaches and supports for autistic people. She outlines recent investigations on sensory processing and nutrition, dietary changes, and supplementation. The speaker discusses recent systematic reviews, highlighting general consensus and gaps in research. Barnhill describes several ongoing studies and future avenues of investigation before the Q&A session.

In this webinar: 

1:30 – Goals and objectives
2:45 – Critical aspects of current discourse
5:28 – Sensory processing and diet
9:15 – Dietary changes
13:40 – Dietary supplements
14:30 – Systematic reviews and meta-analyses
19:00 – Significant findings from the last year
22:00 – Ongoing and future research
29:03 – Q&A

Current discourse and recent publications

Barnhill outlines presentation goals and objectives and highlights the challenges faced by researchers during the COVID-19 pandemic before diving into research updates (1:30).

She summarizes a study that found that 43 autistic participants had significantly higher histamine and lower thiamine than non-austic controls. The speaker asserts that these findings suggest the need for further research into potential interventions and screenings that target these biomarkers (2:45). A study on the impact of dietary quality on executive function found a correlation between poor dietary quality (high intake of processed carbohydrates) and impaired working memory, executive function, and organizational skills (3:58). Barnhill states that dietary factors impact development trajectories and that improving diet quality can improve educational outcomes (4:25). 

Sensory processing and nutrition

The presenter summarizes a study that found autistic children exhibit higher sensory sensitivity to food than their non-autistic peers. Study data also showed lower levels of calcium and vitamin D in the autistic group compared to non-autistic controls. These findings, she continues, reinforce the clinical perspective of food sensitivity in autism, which also emphasizes the impact these sensitivities have on food choices and eating aversions (5:28).

Barnhill cites a study that revealed family units of individuals with food sensitivities also present with different eating profiles (6:00). Another sensory study on BMI found that almost 60% of participants met units for being overweight, and 12% met criteria for thinness or failure to thrive (7:00). These and other studies show autistic children have different eating and feeding styles than non-autistic controls. Barnhill notes that a lot of work is being done to profile how autistic children participate in feeding environments, what their preferences may look like, and appropriate interventions (8:00). 

Dietary changes and supplements

Barnhill explains that a growing body of evidence supports dietary changes and vitamin supplementation in autism. A study involving 400 males and 130 females across multiple facilities in the UK tracked nutrition and development over time. Results showed that adopting a ketogenic diet, with professional support, can be a feasible and appropriate intervention for autistic children (9:15). The speaker cites a survey study that revealed no significant differences in routine while starting a ketogenic diet and that it is easy to assist children in starting the diet if necessary (11:00). Barnhill suggests screening for autism in children who present with significant feeding disorders. 

The speaker describes two animal model studies examining the effect of ketogenic diets on mouse behavior. The first study found that mice on ketogenic diets had reduced social and cognitive deficits and repetitive behaviors and an increased abundance of beneficial microbes in the gut, with no adverse side effects reported. A second study found similar results and also indicated that ketogenic diets may restore histone balances in affected mice (12:15). A third mouse model that tested zinc supplementation saw improvements in social interaction and fear but had no effect on social novelty, or the initiation of new circumstances (13:40).

Systematic reviews and meta-analyses

Barnhill presents a review that found low choline and B vitamins and abnormal amino acids in autistic children compared to non-autistic groups (14:50). Another review on probiotic supplementation found evidence that dietary change can increase oxidative stress. The presenter suggests monitoring oxidative stress as a mark of microbiome changes in the future (16:05). Clinical literature reviews assert that autistic individuals are often deficient in vitamins A, C, B6, and B12. Across reviews of gluten-free/casein-free (GF/CF) diets, there is consensus that GF/CF diets are quite feasible and carry few adverse effects (17:03). Barnhill highlights a review of dietary interventions by Amadi et al. as an excellent source for big picture concepts and detailed questions (18:23). 

The speaker highlights significant studies from the last year that looked at nutrients/probiotics as anti-inflammatories/modulators (19:00), prenatal diets as a modifier for environmental risk factors for autistic traits (19:50), and assessment and data collection methods across studies (20:35). She explains that to best represent typical dietary intake, three-day real-time collection across weekdays and weekends is needed (21:22). 

Ongoing and future research

Barnhill outlines an ongoing study in Florida that explores the impact of eating program interventions (22:25). She also highlights an ongoing longitudinal study assessing the effect of therapeutic GF/CF diet and physiotherapy on the gross motor and cognition of autistic children (23:18). Enrollment is currently open for another exciting study that looks at using folic acid to promote language development (24:01). Finally, the first large study on the impact of mitochondrial function and nutrient intervention is also currently being conducted (25:31). These studies, the speaker asserts, represent a continuous efforts to advance our understanding of autism and identify targeted interventions. 

Barnhill considers future avenues of research and underscores that the most significant barrier to nutritional research is a lack of funding. Contemporary research, she continues, should focus on targeted dietary intakes and anti-inflammatory factors. While GF/CF diets are feasible and effective, she warns against having tunnel vision and reminds viewers that we must always consider more than one avenue (26:30). 

Q & A

During the Q&A (29:03), Barnhill discusses picky eating and nutrition in adulthood (31:40), feeding therapy and dietary changes (36:00), paleo diets and multivitamins (38:00), and Celiac and autoimmune diseases in autism (44:50). She also considers good sources for protein (51:45), vitamins (55:15), and multivitamins (57:05).

In this joint presentation with the World Autism Organization, Frederico Balzola, MD, discusses the intersection of chronic inflammation, gastrointestinal issues, and autism. He considers intestinal permeability and how the microbiome interacts with the central nervous system to affect inflammation in the body. The speaker provides historical context for increased autoimmune and inflammatory diseases and highlights the relationship between GI discomfort/pain and behavioral outcomes. Balzola presents a longitudinal study on inflammatory disease pathogenesis and considers what the results mean for autism medical care moving forward. He summarizes the presentation and critical conclusions before the Q&A. 

In this webinar: 

4:00 – Disease origin and the gut
8:00 – Intestinal permeability
11:30 – Zonulin and the tight junction
15:40 – Societal changes and the gut
18:10 – Food systems, diet, hygiene, and antibiotics
25:00 – The microbiome and immune responses
30:15 – Fecal Microbiota Transfer therapy
34:00 – Gut inflammation in autism
37:15 – Behaviors and GI discomfort
42:00 – Longitudinal study on GI inflammation in autism
48:40 – Results and interpretation
50:15 – Environmental risks
54:55 – Summary and conclusion
1:02:11 – Q&A

Intestinal permeability

Balzola describes how the prevalence of autoimmune and inflammatory diseases has drastically increased over the last four decades. He asserts that this observation reaffirms Hippocrates’s theory that all diseases begin in the gut (4:00). Dr. Alessio Fasano said (5:50), 

“The bowel is a battlefield where enemy and friends negotiate molecular trafficking leading to either tolerance or immune response. It is the largest interface between our body and the outside world.” 

The speaker discusses the role of intestinal permeability in immune system function and how increased permeability can lead to chronic inflammation and allergies (8:00). Balzola outlines the structure of the gut lining and details the evolutionary history of the Tight Junction – a group of 150 proteins that regulate the paracellular trafficking pathway from the bowel to the blood vessels (11:30). Zonulin, the first component of the Tight Junction, appeared in humans 2 million years ago, and was a critical step in evolution as it allowed for regulation across the intestinal lining. The Zonulin gene is on chromosome 16 and has been implicated in diabetes, obesity, and several autoimmune diseases (13:50). 

Societal changes and the gut

Balzola explains how drastic societal and environmental shifts over the last five decades have driven the increase in autoimmune and inflammatory diseases (15:40). He highlights changes in food systems and processing (18:10), diet and meal size (20:55), hygiene and bacterial exposure (22:35), and antibiotic use (24:05). Each of these changes directly impacts the composition of the microbiome and, therefore, the intestinal lining. Contemporary research shows the capacity of the microbiome to influence immune responses and its implication in liver disease, diabetes, autism, Ankylosing Spondylitis, and other inflammatory and autoimmune diseases (28:00). Researchers have also found specific imbalances in the gut that can upregulate Zonulin release, further suggesting that Zonulin is a trigger for inflammation due to its role in intestinal permeability (29:40). 

Gastrointestinal issues in autism

The presenter describes differences in microbiota patterns between autistic and non-autistic individuals (30:15). He touches on fecal microbiota transfer therapy (FMT) and its potential as an effective treatment for gut microbial imbalances in autism and other chronic diseases (31:35). Signs of gut inflammation can be challenging to spot in autistic individuals due to differences in communication and sensory perceptions (34:00). Balzola notes that many autistic people have elevated pain thresholds and difficulties with verbal communication, underscoring the association between behavior and pain expression in autism (36:15). Behaviors commonly associated with gastrointestinal (GI) stress in autism include acid reflux, sleep disturbances, and self-injurious behaviors. The speaker describes possible sitting positions that may help to reduce stomach pain, and illustrates differences in school work outcomes according to levels of pain and inflammation (37:15). 

Balzola outlines a longitudinal study with 1650 participants, where 339 autistic individuals had significant GI symptoms. He presents study participants’ initial family history and GI symptom information, noting that 46% had macroscopic malabsorption and 88% had behavioral disturbances after GI symptoms developed (42:00). GI lab examinations for the study included esophagus, stomach, colon, and rectum (44:30). One participant with inflammatory bowel disease and chronic excess of eosinophils (white blood cells) was treated with the FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) diet. Results showed a reduction in constipation, abdominal pain, proctalgia, and tenesmus, as well as improvements in hyperactivity, motor skills, and mental attention (48:40). At the one-year follow-up, all symptoms were reduced. Researchers, therefore, conclude that there is a significant association between clinical manifestations and histological alterations, meaning that inflammation induces gastrointestinal diseases and their subsequent behaviors (49:21). 

Review and conclusion

The speaker notes that the first 1000 days of life are crucial for clinical inflammatory disease and urges pediatricians to consider this. Environmental risks from pre-conception to postnatal impact inflammatory disease pathogenesis (50:15). He presents a case scenario for cumulative environmental risks, highlighting that the gut microbiome is the result of the sum of every risk and, as such, is very fragile at the beginning (52:30). He summarizes critical points from the presentation and how they translate to changes in perspective and care. Specifically, he urges viewers to consider autism as a multiorgan inflammatory disease and to assume the central nervous system plays a role in intestinal inflammation. He reminds viewers to consider pain thresholds in autistic patients with GI symptoms and to listen to the opinions and experiences of parents to gain a better understanding of autism complexities. Balzola also asserts the need for longitudinal approaches to investigation and medical care to predict and adequately address inflammatory or degenerative diseases (54:55). Most importantly, he continues, it is imperative that evolving information about inflammation in autism is transferred from research to the bedside (1:00:00). He notes Schopenhauer’s three stages of truth before opening to questions (1:01:22). 

10-2-2019 — A new study suggests that children, but not adults, with autism spectrum disorders (ASD) have impairments in interoception. Interoception is the ability to sense the internal state of the body—for instance, to accurately identify sensations such as hunger, thirst, pain, and internal temperature.

Research shows that accuracy in identifying interoceptive signals is associated with skill in emotion processing, decision-making, self-regulation, empathy, and theory of mind (the ability to understand that other people have thoughts and feelings). Toby Nicholson and colleagues, the authors of the new study, say, “These wide-ranging associations are in line with theories of embodied cognition that imply cognition is situated in bodily systems, and also point towards a role for interoception in both self and other processing. This has led to a growing interest in the importance of interoception for disorders such as ASD.”

The researchers say, “The idea is that a difficulty interpreting one’s own internal bodily signals early on may interfere with learning about the association between these low-level bodily signals and other higher level feelings and thoughts, restricting the comprehension of oneself, which in turn would have similar effects on understanding other selves.”

To test the interoceptive accuracy of individuals with ASD, the researchers performed two experiments. In the first, involving 21 adults with ASD and 21 neurotypical controls, participants completed two tasks. First, they closed their eyes and silently counted the number of heartbeats they felt during specific time intervals.

Next, they exhaled into a peak flow meter, attempting to reproduce the intensity of each of three exhalations (weak, medium, and firm). The researchers then repeated the heartbeat experiment with a group of 21 children with ASD and 21 neurotypical children.

The researchers found that children with ASD, but not adults, had significant impairments in interoceptive accuracy. This may suggest, they say, that “a ‘decoupling’ of interoception and emotion processing among some children with ASD results in emotions never being fully anchored within the body, making emotions difficult to understand in self and others across the lifespan even once interoception difficulties have resolved.”

Another possibility, they say, is that “local interoceptive signals are not integrated together in a global sense,” affecting not just emotional processing but also the ability of interoceptive processes to bind with other information sources such as memory and perception. Still a third possibility, they suggest, is that interoception and theory of mind are independently impaired, which could explain why emotion-processing impairments persist in ASD even after interoceptive impairments have resolved.

“Interoception is impaired in children, but not adults, with autism spectrum disorder,” Toby Nicholson, David Williams, Katie Carpenter, and Aimilia Kallitsounaki, Journal of Autism and Developmental Disorders, May 24, 2019 (online). Email: David Williams.

This article also appears in Autism Research Review International, Vol. 33, No. 3, 2019