The unique dietary, medical and behavioural challenges observed in children with ASD combined with an overall lack of data on management of GI disorders in this population presents a pressing need to develop a guideline for nutrition intervention. Common dietary interventions for ASD include:
1. Elimination Diets/Elemental Diet:
Elimination diets (6 foods): Milk, Egg, Wheat, Soy, Peanuts/Tree nuts and Fish/Shellfish
Elemental: All foods except an amino acid based formula
2. Fermentable oligo-di-monosaccharides and polyols:
Foods containing fructose (e.g. fruit, high-fructose corn syrup), lactose (e.g. cow's milk, dairy), fructans (e.g. wheat, onion, garlic), galactans (e.g. legumes) and polyols (e.g. cherries, avocados)
3. Food colouring/food additives avoidance:
Foods that contain food colour additives (food dye)
4. Gluten-free, casein-free:
Foods containing gluten (e.g. bread and pasta) and casein (e.g. cow's milk, yoghurt)
5. Ketogenic diet or modified Atkins diet:
Carbohydrate-rich foods, including sugar
6. Specific Carbohydrate Diet:
Cereal grains (e.g. wheat, oats, rice), processed meats (e.g. lunch and deli meats), canned vegetables, canned fruits, most fruit juices, soy beans, chickpeas, bean sprouts, mung beans, yoghurt, milk, processed cheese, tubers (e.g. potato and yams), curry, onion, powder, garlic.
However, despite the above-mentioned, and an overarching consideration for nutrition management in ASD, empirical investigation has not substantiated the use of dietary manipulation as an ASD-focused treatment. Moreover, without appropriate, researched-based guidance (RBG) the associated risks of the foregoing diets may outweigh any possible benefit that may arise. For example, provisional evidence suggests that use of a gluten-free, casein-diet can lead to greater deficits in bone development among children diagnosed with ASD. Neurologists and Endocrinologists from Harvard University that peripubertal boys with ASD have lower bone mineral density (BMD) than typical developing boys of the same age - However, it remains unclear whether low BMD in ASD results in an increased fracture rate.
Interestingly, it has been observed in a recent study (Journal Of The Academy Of Nutrition and Dietetics) (2016) that despite the lack of evidence on the effectiveness of dietary intervention to influence behavioural expression of ASD, parents often choose to continue the previously mentioned regimes due to perceived benefit, reinforcing the importance of nutrition management to assure a child's diet is nutritionally adequate.
To ensure that appropriate nutrition management is undertaken, registered dietitians (RD) have developed a practical application of nutrition management for gastrointestinal symptoms in ASD specifically constipation and eosinophilic oesophagitis. For example, in the case of constipation the following algorithm may be utilised to ensure appropriate management:
Nutrition Treatment: Increase fluid and fibre in the diet (fruits, vegetables and wholegrains)
Specific Considerations: Will the child consume fruits, vegetables and wholegrains? If yes, are there enough accepted foods in the diet to create a nutritionally adequate diet? If no, should the child be referred for discussions around specific feeding therapy?
Condition: Eosinophilic oesophagitis
Nutrition Treatment: Eliminate allergens in the diet
Specific Considerations: Are there enough foods in the child's repertoire once allergens have been eliminated? Is the allergen-free diet in conflict with a care-giver initiated diet? Does the child need a supplement due to the number of allergens, and will the child accept the supplement.
The examples of the above algorithms (questions) used, appear straightforward, nonetheless, these algorithms are best discussed with a qualified and registered dietitian, specialising in this field. A nutritionist and/or naturopath is not a registered dietitian, and no matter how much experience the practitioner suggests they have, the majority, have limited knowledge and adept understanding of how to successfully manage long-term nutrition outcomes.