Autism is rapidly rising among children in the United States. According to the most current estimates from the Centers for Disease Control and Prevention (CDC), autism is diagnosed in 1 in 63 children in the United States.1 This is up from 1 in 150 diagnosed with autism in 2002, 1 in 110 children in 2006, and 1 in 88 children in 2008.2 Overall, the prevalence of autism increased by 78% between 2002 and 2008 and by 23% between 2006 and 2008.
Key features of autism are well known and include impairments in social interactions; impaired or absent language and communication skills; and a wide range of repetitive behaviors.3 Over recent years, greater recognition has been paid to the myriad comorbidities that accompany autism and that may contribute to the fluctuations in the severity of autistic symptoms, most notably aggression, hyperactivity, and attention. Among these comorbidities, dysfunctions of the gastrointestinal and immunological systems have garnered particular attention because of their common occurrence in children with autism.4,5 Studies report between 30% and 80% of autistic children have symptoms of gastrointestinal dysfunction of which diarrhea is the most common, followed by constipation, abdominal distention, and pain.6 Dysfunctions in immunological systems have also been noted in autistic children, presenting as food allergies or metabolic abnormalities.
Although the etiology of autism remains unknown, the frequently seen dysfunction in the gastrointestinal and immunological systems in children with autism has led to the increasing focus on nutrition and the role it may play in the symptoms of autism.3
Studies are looking at the many factors that contribute to the nutritional status of children with autism, including medical and nutritional aspects and behavioral factors (Table 1).6
Evidence is accumulating on all these factors that may contribute to the nutritional status of children with autism and the potential connection to the comorbid gastrointestinal and immunological dysfunction in these children. To date, however, most studies lack the statistical power to arm physicians with evidence-based treatment recommendations for managing symptoms of autism with nutrition. However, it is increasingly important for pediatricians and other physicians who manage children with autism to become familiar with the evidence to date on various nutritional approaches. This is highlighted by the high percentage of parents who are using some type of complementary and alternative medicine (CAM) to help their children with autism. A 2006 study reported that 74% of families with autistic children were using CAMs, and of these over 54% were using some type of nutritional management such as modified diets and nutritional supplements.3
Given the strong and growing interest in nutrition by those who care for children with autism, pediatricians and healthcare professionals should become familiar with evidence on the different nutritional approaches to managing the symptoms of autism. Although no one nutritional approach will work for all children with autism, given the still unknown etiology of autism and its different presentation in each child, there is growing evidence that nutrition may play a role in managing the symptoms in some children.
The aim of this report is to provide pediatricians with a quick guide on the current evidence for the nutritional management of the symptoms of autism. Research to date has looked at basically 2 nutritional avenues: additive approaches (ie, nutritional interventions and supplementation regimens) and subtractive approaches (ie, elimination regimens based on allergies/food intolerances).
Additive approaches and considerations
A number of nutritional interventions that focus on adding supplements to the diets of autistic children have been investigated over the years. These include supplementation with a variety of vitamins and minerals including vitamin B6/magnesium, vitamin C, vitamin D, vitamin B12, dietary fatty acids (omega-3, cod liver oil), melatonin, folic acid, probiotics, L-carnitine, iron, and zinc and copper.3,4,7 Evidence on a number of these supplements is scarce and ongoing. Table 2 provides a list of the current evidence on the most studied supplements.3,4,7-16
Although evidence to date is limited on these supplements, the need for pediatricians to discuss these options with parents is highlighted by a recent survey that showed that, despite the lack of evidence, parents’ perceive many of these biomedical interventions to be efficacious.17
Subtractive approaches and considerations
Other dietary approaches to managing the symptoms of autism have focused on subtracting or eliminating certain foods from the diet. The rationale behind this approach is that allergies and intolerances to food and food additives may play a role in the symptoms of autism.18 Table 3 lists some of the most widely used diets and the evidence to date on their efficacy and safety in managing symptoms of autism.3,5,7,19-22 Similar to supplements, most of the current research lacks sufficient evidence on which to base recommendations.
A growing body of evidence is emerging on the potential role of nutrition to help manage the symptoms of autism. Although the evidence to date is limited and cannot be used to generate evidence-based recommendations, sufficient data exists on some nutritional approaches that may warrant their use. Pediatricians and other healthcare professionals need to work with individual parents and their autistic children to incorporate potential nutritional approaches. For example, pediatricians need to work with parents to monitor and report behavioral changes following dietary adjustments (see “Best Practices: Additional Resources”).
Because of the complexity of the symptoms of autism that include both physiologic and behavioral/psychological difficulties, management of symptoms should include a multidisciplinary team that includes a dietician, a pediatric gastroenterologist and/or pediatric allergist, and a behavioral/developmental pediatrician, as well as others who can help with particular challenges (eg, speech pathologist, physical therapist, and psychologist).7
Although the etiology of autism remains unknown, increased recognition of the high prevalence of gastrointestinal and immunosuppression dysfunction in children with autism has contributed to the growing interest in evidence looking at the relationship between the gut microbiome and the development and function of the nervous system and behavior.23 Animal studies in rodents have shown the many ways in which neurobehavioral development is influenced by the gut microbiome.
Future research on the role the gut microbiome plays in the development of the nervous system and behavior disorders will further help target appropriate nutritional pathways to manage the symptoms of autism. Future studies, along with a number of randomized controlled trials currently under way,24 will continue to clarify the role of nutrition in helping manage the symptoms of children with autism.
1. Developmental Disabilities Monitoring Network Surveillance Year 2010 Principal Investigators. Prevalence of autism spectrum disorder among children aged 8 years—Autism and Developmental Disabilities Monitoring Network, 11 sites, United States, 2010. MMWR Surveill Summ. 2014;63(suppl 2):1-21.
2. Autism and Developmental Disabilities Monitoring Network Surveillance Year 2008 Principal Investigators; Centers for Disease Control and Prevention. Prevalence of autism spectrum disorders—Autism and Developmental Disabilities Monitoring Network, 14 sites, United States, 2008. MMWR Surveill Summ. 2012;61(3):1-19.
3. Marti LF. Dietary interventions in children with autism spectrum disorders—an updated review of the research evidence. Curr Clin Pharmacol. September 20, 2013. Epub ahead of print.
4. Kawicka A, Regulska-Ilow B. How nutrition status, diet and dietary supplements can affect autism. A review. Rocz Panstw Zakl Hig. 2013:64(1):1-12.
5. Buie T, Campbell DB, Fuchs GJ 3rd, et al. Evaluation, diagnosis, and treatment of gastrointestinal disorders in individuals with ASDs: a consensus report. Pediatrics. 2010;125 (suppl 1):S1-S18.
6. Geraghty ME, Depasquale GM, Lane AE. Nutritional intake and therapies in autism: a spectrum of what we know: part 1. Infant Child Adolesc Nutr. 2010;2(1):62-69. Available at: http://can.sagepub.com/content/2/1/62. Accessed March 20, 2014.
7. Geraghty ME, Bates-Wall J, Ratliff-Schaub K, Lane AE. Nutritional interventions and therapies in autism: a spectrum of what we know: part 2. Infant Child Adolesc Nutr 2010;2(2):120-133. Available at: http://can.sagepub.com/content/2/2/120. Accessed March 20, 2014.
8. Adams JB, Holloway C. Pilot study of a moderate dose multivitamin/mineral supplement for children with autistic spectrum disorder. J Altern Complement Med. 2004;10(6):1033-1039.
9. Adams JB, George F, Audhya T. Abnormally high plasma levels of vitamin B6 in children with autism not taking supplements compared to controls not taking supplements. J Altern Complement Med. 2006;12(1):59-63.
10. Mousain-Bosc M, Roche M, Polge A, Pradal-Prat D, Rapin J, Bali JP. Improvement of neurobehavioral disorders in children supplemented with magnesium-vitamin B6. II. Pervasive developmental disorder-autism. Magnes Res. 2006;19(1):53-62.
11. Dolske MC, Spollen J, McKay S, Lancashire E, Tolbert L. A preliminary trial of ascorbic acid as supplemental therapy for autism. Prog Neuropsychopharmacol Biol Psychiatry. 1993;17(5):765-774.
12. Tsalamanios E, Yanni AE, Koutsari C. Omega-3 fatty acids: role in the prevention and treatment of psychiatric disorders. Curr Psychiatr Rev. 2006;2(2):215-234
13. Melke J, Goubran Botros H, Chaste P, et al. Abnormal melatonin synthesis in autism spectrum disorders. Mol Psychiatry. 2008;13(1):90-98
14. Rossignol DA. Novel and emerging treatments for autism spectrum disorders: a systematic review. Ann Clin Psychiatry. 2009;21(4):213-236.
15. Ulbrich T, Plogsted S, Geraghty M, Reber KM, Valentine CJ. Probiotics and prebiotics: why are they “bugging” us in the pharmacy? J Pediatr Pharmacol Ther. 2009;14(1):17-24
16. Pham M, Lemberg DA, Day AS. Probiotics: sorting the evidence from the myths. Med J Aust. 2008;188(5):304-308.
17. Adams JB. Summary of Dietary, Nutritional, and Medical Treatments for Autism—based on over 150 published research studies. Publication 40—2013 version. San Diego, CA: Autism Research Institute; 2013:53. Available at: http://ariconference.com/enews/treatment.pdf. Accessed March 20, 2014.
18. Curtis LT, Patel K. Nutritional and environmental approaches to preventing and treating autism and attention deficit hyperactivity disorder (ADHD): a review. J Altern Complement Med. 2008;14(1):79-85.
19. Elder JH. The gluten-free, casein-free diet in autism: an overview with clinical implications. Nutr Clin Pract. 2008-2009;23(6):583-588
20. Millward C, Ferriter M, Calver S, Connell-Jones G. Gluten- and casein-free diets for autistic spectrum disorder. Cochrane Database Syst Rev. 2008;(2):CD003498.
21. Evangeliou A, Vlachonikolis I, Mihailidou H, et al. Application of a ketogenic diet in children with autistic behavior: pilot study. J Child Neurol. 2003;18(2):113-118.
22. Strickland E. Eating for Autism: The 10-Step Nutrition Plan to Treat Your Child’s Autism, Asperger’s, or ADHD. Philadelphia, PA: Da Capo Press; 2009.
23. Mulle JG, Sharp WG, Cubells JF. The gut microbiome: a new frontier in autism research. Curr Psychiatry Rep. 2013;15(2):337.
24. Alanazi AS. The role of nutraceuticals in the management of autism. Saudi Pharm J. 2013;21(3):233-243.