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).
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).
