Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition that affects the social communication of a person, involves repetitive interests and behaviours, and impacts sensory functioning. Children with ASD may also have restricted interests and struggle with sensory sensitivity. In addition, they may also experience anxiety, attention deficits, and depression.
Due to the complexity and diversity of ASD, an interdisciplinary team approach is necessary to understand its impact on different aspects of a child. Although nutrient intake is an indicator of a child’s health, the assessment of nutrient intake is not part of the routine screening for children with ASD.
One of the most fundamental activities that humans do is to eat. The nutrients we obtain from the food we eat are essential for developing and continuing life. Limited nutrient intake affects development and health outcomes, such as obesity, bone density, and cardiovascular disease, which may last through adulthood. Nutritional deficiencies can also lead to metabolic disorders, negatively impacting perceptual skills used for initial information processing and interpreting sensory input.
Nutritional Status of Children with ASD
It is common knowledge that children with ASD exhibit food selectivity. They may refuse food, eat only a small number of acceptable foods, frequently consume a single food, excessively consume a small number of foods, or selectively consume particular food categories (such as carbohydrates, fats, or proteins). Studies observed that the restricted food acceptance behaviour in children with ASD was seen across all food groups except carbohydrates.
Food selectivity impacts the variety of food intake, which affects the nutritional intake of children with ASD. Tsujiguchi et al. found that children, between 7-12 years old, with ASD traits, consumed relatively less sodium, calcium, magnesium, iron, vitamin D, vitamin B2, and vitamin B12, than those without (2022). The researchers believed that the lower consumption of animal products, fish, or pulses in children with ASD might cause their slightly lower protein intake. Limited consumption of fruit and vegetables leads to lower levels of micronutrients, and reduced consumption of dairy products may lead to lower calcium intake.
When the researchers followed up with the students three years later, they noted that the dietary uniformity persisted into later childhood. Children with ASD are more susceptible to the long-term effects of nutrition inadequacy, which may lead to an increase in deficiency and result in adverse health outcomes.
In the Mediterranean, Marí-Bauset et al. found that children with ASD did not meet the dietary recommendations for calcium, thiamin, riboflavin, and vitamin C. Compared to their typically developing peers, children with ASD had a higher risk of being underweight as they consumed fewer dairy and cereal products. As part of the traditional Mediterranean diet, they consumed more vegetables, legumes, fibre, and some micronutrients but had less sodium, iodine, and calcium in their diet. (2016)
Among the studies, one of the most common nutrients that children with ASD lack are calcium. Research investigating the relationship between nutrient intake and bone health revealed that boys with ASD may be at higher than average risk for thinner and less dense bones because of their unusual food preferences and dairy-free diets.
In addition to children’s food preferences and behaviour, parents may also adopt restricted diets such as gluten-free or casein-free diets for various reasons. Research found that those who followed a casein-free diet had chronically low intakes of calcium and vitamin D, which resulted in thinner bones. Their bones are 19% thinner than typically developing boys within the same age range.
Marí-Bauset et al. observed that the reduced calcium intake in casein-free diets led to a decrease in lactose and vitamin D, which was associated with lower bone density. At the same time, the folate and vitamin B6 deficiencies observed in gluten-free diets increase cardiovascular risk in the medium to long term. These findings suggest that there are risks in adopting restricted diets without a proper diagnosis of intolerance or allergy towards these foods (2014).
Factors Affecting the Nutrition Intake of Children with ASD
The nutritional status of children with ASD can be affected by various factors, and they can be broadly categorised into behavioural and medical factors. Factors that affect their eating behaviours include those that manifest as a result of ASD and family factors. Medical factors relate to comorbidities, food allergies, and medicinal side effects.
In children with ASD, restricted and repetitive patterns of behaviours, interests, or activities may also lead to self-restrictive eating behaviours. Besides food selectivity, up to 89% of children with ASD may also engage in other eating behaviours such as having specific and dysfunctional mealtime routines (e.g., one food is not allowed to touch another food, using only specific utensils, need for sameness in eating arrangement), throwing tantrums, or other non-compliance behaviours. They may also have oral-motor deficits that lead to issues with feeding.
Although similar problem eating behaviours are found in typically developing children, managing these behaviours in children with ASD seems more challenging. Additionally, the behaviours last longer into childhood and are more intense than those in typically developing children. In many cases, caregivers of children with ASD have to deal with multiple problem eating behaviours, which significantly increases their stress and load.
Parental stress, control and emotional reactions to behaviours can affect a child’s eating habits and, in turn, their nutritional status. Parents of children with ASD have stronger emotional responses to their child’s eating behaviours and perceive their children’s eating habits more negatively, feeling the need to exert more control over them. Having a selective eater may also mean that the family has to make compromises around mealtime routines. Besides having lesser opportunities to eat and socially engage in public places, they also face disrupted family mealtimes. The agitation and resistance faced during mealtimes can further increase levels of caregiver stress.
Children with ASD commonly have sensory processing issues. Sensory processing refers to how a child responds to tactile, vestibular, auditory, visual, gustatory, and olfactory stimuli. Having heightened or subdued responses to stimuli can affect their eating experience and thus impacts eating behaviours. Some research suggests that food avoidance and restriction can be caused by hypersensitivity to particular food textures, tastes, or odours, making the intense flavours and textures in fresh fruits and vegetables harder for children with ASD to accept.
In preliminary research, Geraghty, Depasquale, et al. found that between 30% and 80% of autistic children experience gastrointestinal (GI) symptoms, and 43% may have a “leaky gut”. GI symptoms can include dyspepsia, IBS, functional abdominal pain, chronic abdominal pain or discomfort, gastroesophageal reflux, chronic diarrhoea or constipation, all of which may affect mealtimes for the child. (2010)
Allergies to certain foods may also necessitate restriction or avoidance. In such cases, parents may opt for a restricted diet such as a casein-free or gluten-free diet. Studies found that children with ASD can outgrow some allergies to milk proteins. So, temporary avoidance, not long-term restriction, maybe the key to maintaining healthy nutrition.
Some prescribed medications, such as stimulants, antiepileptics, and atypical antipsychotics, used to help with disruptive and maladaptive behaviours may have adverse effects on nutrition. They may cause a loss of appetite, nausea, gastrointestinal irritation, and more.
Nutrient Intake Affects Health and Behaviour
Some studies suggest that nutrient deficiencies could cause some of the disorder’s symptoms. Adams & Conn pointed out that there is research demonstrating evidence of change in the social, communicative, and cognitive aspects of children with ASD with diet/vitamin therapy. (1997) Although these studies require better-controlled study methods to determine the link between diet, vitamins and behaviour, they shed light on the impact of nutrients on health and behaviour.
Children with ASD are at risk of inadequate nutritional intake, whether due to their selective and problem eating behaviours or from a restricted diet decided by the parent. As such, a nutrient intake assessment is recommended as part of the routine screening. By understanding their current nutritional status and the factors that impact their eating, appropriate interventions and support can be applied, helping children with ASD lead healthier lives.
Other articles about Understanding Children with ASD:
- Benefits of Exercise on Sleep and Behaviour
- How Music Affects Speech
- How Face Perception Affects Social Skills
Geraghty ME, Bates-Wall J, Ratliff-Schaub K, Lane AE. Nutritional Interventions and Therapies in Autism: A Spectrum of What We Know: Part 2. ICAN: Infant, Child, & Adolescent Nutrition. 2010;2(2):120-133. doi:10.1177/1941406410366848
Geraghty ME, Depasquale GM, Lane AE. Nutritional Intake and Therapies in Autism: A Spectrum of What We Know: Part 1. ICAN: Infant, Child, & Adolescent Nutrition. 2010;2(1):62-69. doi:10.1177/1941406409358437
Marí-Bauset S, Zazpe I, Mari-Sanchis A, Llopis-González A, Morales-Suárez-Varela M. Evidence of the Gluten-Free and Casein-Free Diet in Autism Spectrum Disorders: A Systematic Review. Journal of Child Neurology. 2014;29(12):1718-1727. doi:10.1177/0883073814531330
Marí-Bauset, S., Llopis-González, A., Zazpe, I., Marí-Sanchis, A., & Morales Suárez-Varela, M. (2017). Comparison of nutritional status between children with autism spectrum disorder and typically developing children in the Mediterranean Region (Valencia, Spain). Autism, 21(3), 310–322. https://doi.org/10.1177/1362361316636976
Tsujiguchi, H., Hara, A., Miyagi, S., Pham, K. O., Suzuki, K., Nguyen, T. T. T., Ono, Y., Kambayashi, Y., Shimizu, Y., Nakamura, H., Suzuki, F., Shibata, A., Hayashi, K., Tsuboi, H., & Nakamura, H. (2022). Prospective relationship between autistic traits and nutrient intakes among Japanese children: Results of the Shika study. Autism, 0(0). https://doi.org/10.1177/13623613221097487