OBJECTIVE: To investigate the feeding, diet and growth of young children with autism spectrum disorders (ASD).
METHOD: Data on feeding and food frequency were collected by questionnaires completed at 6, 15, 24, 38 and 54 months by participants in the Avon Longitudinal Study of Parents and Children. A food variety score was created, and the content of the diet was calculated at 38 m. The feeding and dietary patterns of 79 children with ASD were compared with 12 901 controls.
RESULTS: The median ages of ASD children were 28 months at referral and 45 months at diagnosis. ASD infants showed late introduction of solids after 6 months (p = .004) and were described as “slow feeders” at 6 months (p = .04). From 15–54 months ASD children were consistently reported to be “difficult to feed” (p < .001) and “very choosy” (p < .001). From 15 months, the ASD group had a less varied diet than controls, were more likely to have different meals from their mother from 24 months, and by 54 months 8% of ASD children were taking a special diet for “allergy.”
ASD children consumed less vegetables, salad and fresh fruit, but also less sweets and fizzy drinks. At 38 months intakes of energy, total fat, carbohydrate and protein were similar, but the ASD group consumed less vitamins C (p = .02) and D (p = .003). There were no differences in weight, height or BMI at 18 months and 7 years, or in hemoglobin concentrations at 7 years.
CONCLUSIONS: ASD children showed feeding symptoms from infancy and had a less varied diet from 15 months, but energy intake and growth were not impaired.
WHAT'S KNOWN ON THIS SUBJECT:
Children with ASDs are often reported to have limited food preferences and behavioral difficulties associated with feeding. However, the age of onset of feeding symptoms and the impact on diet and growth are poorly understood.
WHAT THIS STUDY ADDS:
Using prospectively reported data the authors found that children with ASDs showed feeding symptoms from infancy and had a less varied diet from 15 months of age, but energy intake and growth were not impaired.
Autism spectrum disorders (ASDs) are characterized by impairments in social interaction and communication and stereotypical and repetitive behaviors. People with ASDs are often resistant to change and have a narrow range of interests, which can extend to the foods they like.1 Children with ASDs are often reported to have unusual eating patterns with a restricted range of food choices.2 However, the differences are not only a result of impairments intrinsic to the child with an ASD; a questionnaire survey of parents of children with ASDs revealed that family food preferences seemed to influence food selection more than the diagnostic characteristics of autism.3
Other feeding symptoms have also been reported. A retrospective study of children with ASDs revealed that vomiting, reflux, colic, and failure to feed were more common in those with Asperger syndrome than in those with other autism disorders.4
Much of the published literature has been based on small clinical samples with no control group, and some have used retrospectively collected data on feeding. We have used a population-based cohort to investigate feeding patterns, diet, and growth of children with ASDs and used prospectively reported data collected before the diagnosis of an autism disorder had been made.
The Avon Longitudinal Study of Parents and Children (ALSPAC) is a longitudinal cohort study that follows the health and development of children who had an expected date of delivery between April 1991 and December 1992 and resided in the Avon area of southwest England at the time of their birth.
Mothers (n = 14 541) enrolled during pregnancy, and those pregnancies resulted in 14 062 live births, of whom 13 971 survived their first 5 years.5 Full details of the questionnaires used, the biological samples retained, the examinations, and observations of the children are available on the ALSPAC Web site.6 Ethical approval for the study was obtained from the ALSPAC Law and Ethics Committee and the local research ethics committees.
Identification of Cases of ASD
The children within the ALSPAC with a diagnosis of ASD by the age of 11 years were identified from 2 independent sources: (1) the clinical records of all children in the cohort investigated for a suspected developmental disorder by a multidisciplinary assessment; and (2) the national educational database in England (Pupil Level Annual School Census [PLASC]), which identified all children in state schools (>90% of children) who needed special educational provision because of ASDs in 2003. Details of the methods used in the identification of ASDs and the demographic characteristics of the autistic children in the ALSPAC cohort have already been reported.7 A total of 86 children were identified, giving a prevalence of 62 per 10 000 children aged 11 years. There were 30 children with classical childhood autism, 15 with atypical autism, and 23 with Asperger syndrome; 18 of the ASD cases could not be classified. The median age of referral was 28 months, and the median age of diagnosis of childhood autism was 45 months.
Feeding and Dietary Data
Questions on the child's feeding and the frequency with which different foods were eaten were included in questionnaires completed by the main caregiver at 6, 15, 24, 38, and 54 months. A food-variety score was created from the food-frequency questionnaires: a total of 56 different foods and drinks were included, and the number of times “never” was reported was summed to give the food-variety score. The higher the score, the less variety in the diet.
The content of the diet was assessed from the food-frequency questionnaire completed by the caregiver when the child was 38 months of age.
Weight and height measurements collected by health visitors as part of routine preschool-aged child health surveillance were extracted from the Avon Child Health Computer database. At the age of 7 years, all children in the ALSPAC were invited to a special research clinic at which they were weighed and measured.
Children who attended the ALSPAC research clinic at 7 years of age had venous blood samples taken for hemoglobin analysis by the HemoCue (L.E. West, Ltd, Barking, United Kingdom) method (n = 5859).
Logistic regression was used to analyze associations between ASDs and feeding patterns by using Stata 9.2 (Stata Corp, College Station, TX). Because of the strong association between gender and ASDs (odds ratio [OR]: 6.40 [95% confidence interval (CI): 3.42–12.14]), analyses were adjusted for gender. A linear relationship was assumed for continuous variables (food-variety score and dietary intakes). Effect sizes were reported for a 1-SD increase. Categorical variables (feeding patterns) were dichotomized according to the worst versus the rest of the categories. Repeated measures at different ages were analyzed simultaneously in a combined analysis but, for clarity, are reported separately. In these combined analyses, additional adjustment was made for age, and differences in effects across time were assessed through an interaction test.
Data on feeding and dietary patterns were available for 79 children with ASDs and 12 901 controls. Actual numbers varied for each explanatory variable and were in the range of 64 to 74 for children with ASDs and 9550 to 12 249 for controls.
No group differences were apparent in maternal diet during pregnancy, breastfeeding rates, or infant food-variety score at 6 months. In infancy, the children subsequently diagnosed with ASDs were more likely than controls to have late acceptance of solid food (P = .004) and to be described by their mothers as “slow feeders” (P = .02) (Table 1).
Between 15 and 54 months of age, the children with ASDs were consistently reported to be difficult to feed (P < .001) and very choosy (P < .001). Results of combined analyses suggested that these differences were present at 15 months. From 15 months, the children with ASDs had a significantly less varied diet, which became progressively more different than controls with increasing age (interaction P = .002). The diet was least varied in children with classical autism (Fig 1). At 38 months the food-variety score was normally distributed, with a mean of 21 (SD: 6; range: 2–48).
By 24 months of age, the children with ASDs were more likely to be having a different diet than the rest of their family, and by 54 months 8% of the children with ASDs were taking a special diet for “allergy,” compared with 2% of controls (OR: 3.41 [95% CI: 1.35–8.63]; P = .01). Children with ASDs were much more likely than controls to show pica behavior at 38 and 54 months (Table 1).
The food-frequency data showed that, compared with controls, the children in the ASD group ate fewer vegetables, salads, and fresh fruit but also consumed fewer sweets and fizzy drinks. The derived dietary data at 38 months (Table 2) revealed no differences between children with ASDs and control children in the reported intake of energy, total fat, carbohydrate, proteins, and minerals, but the group of children with ASDs had less variety in their diet (higher variety score). The details of the diet are contained in the Appendix, which shows that the dietary content of children with classical autism, atypical autism, and Asperger syndrome were similar. Compared with controls, children with ASDs consumed less vitamin C (P = .007) and vitamin D (P = .004) and more iodine (P = .01), but estimates were imprecise because of small sample sizes within some groups.
There were no group differences between children with ASDs and controls in mean weight, height, or BMI at 18 months and 7 years. Although children with ASDs had slightly lower mean hemoglobin levels (122.7 vs 124.5 g/L), this difference was not significant (P = .320).
The results of this prospective study show that children on the autism spectrum demonstrated feeding symptoms from infancy and had a progressively less varied diet from 15 months of age. However, energy intake and growth were not impaired. The limitation in number of foods accepted was most apparent in children with classical autism, but no other differences were apparent between different types of autism disorders in feeding symptoms, diet, or growth.
The strengths of the study are that the sample is population based, which provides a good normal comparative group and that feeding data have been collected prospectively before ASD was diagnosed. Limitations are that ASDs in the children were diagnosed by clinical teams rather than by a structured research assessment, and the feeding and dietary data were reported by the mother with no objective validation.
The finding that breastfeeding rates of the children with ASDs were no different than those of controls is consistent with the results of an earlier study from North Dakota.8 The difficulty in accepting solids and the description of slow feeding in infancy could be seen as early symptoms of an autistic child's difficulty in accepting change. Other feeding symptoms such as fussiness became more obvious with increasing age and are most marked in the children with classical autism. The restrictions in types of food accepted by the child with an ASD were apparent from 15 months of age, often before referral for specialist autism assessment, and became progressively more obvious.
A clinical implication of these findings is that the possibility of an ASD should be considered for young children who present with feeding problems, pervasive food refusal, and limited food preferences, and appropriate questions should be asked about the child's social communication, shared attention, and stereotypic and self-stimulatory behaviors.
For children who have ASDs and pervasive eating problems, effective behavioral strategies need to address both the neophobia and sensory sensitivities (color, taste, texture) of the autistic child. Tools such as the Brief Autism Mealtime Behavior Inventory (BAMBI)9 have been developed to assess feeding problems in children with ASDs and provide a useful objective measure to monitor response to behavioral interventions to improve the range of foods taken.
Clinicians and parents will be reassured by the finding that, despite the limited food preferences, the children with ASDs took adequate amounts of energy from their diet and grew normally. No differences were found between children with ASDs and their peers in the balance of carbohydrates, protein, and fats consumed, which suggests that satiety mechanisms are not impaired in ASDs. No differences were apparent in minerals in the diet, including iron and calcium. Our results are consistent with those of recent descriptive studies that also found that, although the parents of children with ASDs reported that they were picky eaters and resisted trying new foods, the measured nutrient intake of the children with ASDs was similar to that of age-matched controls.10
With >30 dietary components being compared, some associations may be have been a result of chance, so the finding that 2 vitamins were reduced in the ASD diet needs to be treated with caution. The lower vitamin C intake is derived from the lower consumption by the children with ASDs of fruits and vegetables reported in the food-frequency questionnaires. However, the children with ASDs had similar iron intake and hemoglobin levels to those of controls. The children with ASDs also less frequently accepted dietary sources of vitamin D and had more iodine in their diet, but the clinical significance of these findings is uncertain. In comparison, a recent smaller, detailed study that compared 3-day dietary diaries of children with ASDs and children with typical development11 revealed that children with ASDs consumed more vitamins B6 and E and nondairy protein but less calcium with fewer dairy servings.
A few autistic children in the ALSPAC were placed on special diets after the diagnosis of ASD had been made, with the parents citing allergy as the reason for the diet, but we did not have information on how food allergy was diagnosed. The dietary changes may have been made in response to the gastrointestinal symptoms that are reported for autistic children12,–,15 or to attempt to improve core autistic behaviors such as ability to communicate. Although many parents of children with ASDs do try special diets for their children, a recent update of a Cochrane review on gluten- and casein-free diets in children with ASDs concluded that the evidence for the efficacy of these diets remains poor.16
The normal dietary consumption of energy by the children with ASDs in our study is reflected in their normal growth parameters, consistent with the literature on growth in children with autism disorders.17 However, in some societies, children with autism are at higher risk of being overweight.18
Children on the autism spectrum demonstrated feeding symptoms from infancy and had a less varied diet from 15 months of age, but energy intake and growth were not impaired. Feeding behavior in children with ASDs reflects limited interests and difficulty in accepting change and, in an extreme form, can present as a “pervasive eating disorder.”
The UK Medical Research Council, the Wellcome Trust, and the University of Bristol provide core support for the ALSPAC. This study was funded by the Medical Research Council: all researchers on this study are independent from the funding body, and there are no competing interests to declare. This publication is the work of the authors, and Drs Emond and Steer will serve as guarantors for the contents of this article.
We are extremely grateful to all the families who took part, the midwives for help in recruiting them, and the whole ALSPAC team, which includes interviewers, computer and laboratory technicians, clerical workers, research scientists, volunteers, managers, receptionists, and nurses.
- Accepted April 27, 2010.
- Address correspondence to Jean Golding, PhD, Centre for Child and Adolescent Health, Barley House, Oakfield Grove, Bristol BS8 2BN, United Kingdom. E-mail:
FINANCIAL DISCLOSURE: The authors have indicated they have no financial relationships relevant to this article to disclose.
- ASD =
- autism spectrum disorder •
- ALSPAC =
- Avon Longitudinal Study of Parents and Children •
- OR =
- odds ratio •
- CI =
- confidence interval
- 6.↵University of Bristol. Avon Longitudinal Study of Parents and Children. Available at: www.alspac.bristol.ac.uk. Accessed June 3, 2010
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- Steer C,
- Golding J,
- Emond A
- Molloy CA,
- Manning-Courtney P
- Ibrahim SH,
- Voigt RG,
- Katusic SK,
- Weaver AL,
- Barbaresi WJ
- Millward C,
- Ferriter M,
- Calver S,
- Connell-Jones G
- Copyright © 2010 by the American Academy of Pediatrics