Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder that affects communication, social interactions, and behaviour. ASD is thought to be seen in 1% of the population (National Collaborating Centre for Mental Health 2012). ASD diagnosed children often have difficulty with sensory processing, including food selectivity, which has the potential to lead to inadequate nutrient intake and poor growth. As a result, there is an increasing interest in exploring the role of nutrition interventions in improving outcomes for children with ASD. In this article, we will explore the current evidence on the effectiveness of nutrition interventions in managing the symptoms of ASD.
Food selectivity, or the restriction of certain foods, is common among the ASD population. It can lead to inadequate nutrient intake, which can contribute to poor growth, nutritional deficiencies, and other health complications. Studies have shown that children with ASD are more likely to have nutritional deficiencies in micronutrients such as vitamin D, calcium, and zinc (Esteban-Figuerola et al., 2019). In addition, research has found that children with ASD are more likely to have gastrointestinal issues, such as constipation and diarrhoea, which can further impact their nutritional status (Ristori et al., 2019).
Several nutrition interventions have been proposed as potential treatments for ASD. This article outlines the diets and the research around it, it is intended to provide you with information but not be a clinical guide or recommendation. This research is in the early stages and not yet included in general guidance. Any restrictive diet should be done with the support of a healthcare professional. I have included diet types that have had more research conducted around them, as well as common diet types I have come across for ASD children, in the hope to provide some background information to supplement the individual experiences that can be shared. These diets include gluten-free/casein-free diets, ketogenic diets, vitamin D supplementation, and omega-3 fatty acid supplementation.
Gluten-Free/Casein-Free Diets
A gluten-free/casein-free (GFCF) diet involves the elimination of all foods containing gluten (found in wheat, barley, and rye) and casein (found in dairy products) from the diet. The theory behind this diet is that certain proteins in gluten and casein may be poorly digested in some individuals, leading to inflammation and other negative effects on the brain and behaviour. While some parents and caregivers report improvements in behaviour and gastrointestinal symptoms in children with ASD on a GFCF diet, the evidence is mixed. Quan et al (2022) and Keller et al (2021) conducted systematic reviews and meta-analysis combining a total of 14 studies. While there was some evidence that could indicate a GFCF diet can reduce symptoms of ASD the studies used were reported to be low in quality and any introduction of this diet type to children should be done with careful consideration. Further research is needed to better understand the potential benefits of this diet for children with ASD. Overall, I would be mindful of introducing a diet this restrictive to a child, especially if their diet is already restricted with their food choices, unless under the guidance of a nutritionist or dietician.
For a more in depth look at GF/CF about gluten-free/casein-free diets, please view our article written by the world renowned Dr Alex Richardson:
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Ketogenic Diet
A ketogenic diet is a high-fat, low-carbohydrate diet that has been used to treat epilepsy and other neurological disorders. The diet is thought to work by increasing the production of ketones, which can provide an alternative energy source for the brain. Some studies have suggested that a ketogenic diet may also be beneficial for children with ASD. A scoping review (Varesio et al, 2021) looked at 7 studies, some of these studies reported improvements in behaviour and emotional responses, such as reduced aggression. However, these studies had small sample sizes, different methods of measuring the reduction in ASD symptoms and many were short term. Larger and longer studies are needed to confirm these findings and to determine the safety and long-term effects of a ketogenic diet in children with ASD. Research looking into the ketogenic diet for other neurological disorders often finds adherence to the diet challenging, especially for children as it is an incredibly restrictive diet. This is another diet I would be very mindful of introducing to a child with an already restrictive diet, please ensure you seek support from a nutritional professional if you are considering this diet type.
Vitamin D Supplementation
Vitamin D is an essential nutrient that plays a role in bone health, immune function, and other physiological processes. Research suggests that individuals with ASD may have lower levels of vitamin D than the general population (Guo et al., 2019). Some studies have suggested that vitamin D supplementation may improve symptoms of ASD. One study found that high-dose vitamin D supplementation improved autism symptoms in children with low levels of vitamin D (Saad et al., 2016). However, more research is needed to determine the optimal dose and duration of vitamin D supplementation for children with ASD.
Vitamin D is more researched in the general population and is recommended for those living in the UK during autumn and winter. Individuals who spend less time outdoors or cover up most of their skin when outdoors are also more likely to benefit from supplementation all year round. Overall, this is a simple and easy way to support the diet of ASD children and unlike the previously discussed diets does not involve a high level of restriction.
Omega-3 Fatty Acid Supplementation
Omega-3 fatty acids are essential fats that play a role in brain function and development. Some studies have suggested that omega-3 fatty acid supplementation may improve symptoms of ASD. One small pilot study found that omega-3 fatty acid supplementation improved social interaction and communication in children with ASD (Amminger et al., 2007). However, a systematic review and meta-analysis of 13 studies identified a lack of evidence for omega-3 fatty acid supplementation to reduce symptoms of ASD (Wobido et al, 2022). We do know that a diet containing oily fish or omega 3 supplementation is important for the general population, so this could be another way to support overall diet without restriction.
Take an indepth look at omega-3 fatty acids and how they may benefit individuals with autism:
Conclusion
While the evidence on the effectiveness of nutrition interventions for ASD is mixed, there is some research to suggest that certain interventions may be beneficial for some children with ASD. However, it is important to note that not all children with ASD will respond to these interventions, and that more research is needed to identify which children are most likely to benefit. In addition, nutrition interventions should always be used in conjunction with other evidence-based treatments for ASD, such as behavioural therapy and medication.
In conclusion, while there is still much that is not known about the relationship between diet and ASD, the emerging evidence suggests that certain nutritional interventions may help improve the symptoms of ASD. A diet containing a variety of nutrients to avoid nutritional deficiencies would be the best place to start, this could look like the Mediterranean diet. Supplementation to support any food avoided could then be helpful where a balanced diet is not tolerated. Any further diet restriction should then be done with the support of a healthcare professional.
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Disclaimer: The views and opinions expressed in this blog post are those of the author and do not necessarily reflect the official policy or position of any professional organization or guidelines. The information provided is for educational and informational purposes only and is not intended as a substitute for professional advice, diagnosis, or treatment. Always seek the advice of your therapist or other qualified health provider with any questions you may have regarding a medical or mental health condition.