News and Notes about Scientific Research on Autism and other Developmental and Behavioral Disorders

Editor: Bill Ahearn, Ph.D., BCBA
Director of Research, The New England Center for Children

Diet Therapies as Treatment for Autism

Dietary restrictions and fad diets have been suggested as treatments for autism and a variety of other disabilities (e.g., Feingold, 1975; Reiten, 1987). The theory that food allergies cause or contribute to autism has no sound scientific evidence supporting it. Moreover, New York State’s Department of Health sponsored an independent panel of parents and professionals to develop clinical practice guidelines for providing services to children with autism or pervasive developmental disorders (NYSDHEIP, 1999). One of the many of the tasks of this panel was to review interventions for children with autism. The panel found no evidence to support the use of diet therapies as treatments for autism and does not recommend their use. There was also no sound scientific evidence to support the theory that food allergies cause or contribute to autism. Additionally, they concluded that intradermal testing or blood tests for specific antibodies do not help to develop treatments for autism.

Research conducted at NECC has found that children with autism seem to be prone to have eating habits that are highly selective (Ahearn, Castine, Nault, & Green, 2001). That is, they tend to be picky eaters and starches are the foods they are most likely to prefer. Reiten (1987) suggested that it is likely these picky eating habits were produced by the children having difficulty tolerating the foods they rejected. One of the substances that some speculate children with autism are unable to adequately process is a wheat product, gluten. There is no reason to believe that a substance, if it produced an unpleasant reaction or feeling, would continue to be readily consumed by the child. More importantly, because children with autism are prone to selective eating habits, placing them on diets that will further restrict the foods that they are presented with may cause the child with selective eating habits to become more selective, they may produce selective eating habits for children that are not selective, and they can lead to nutritional deficiencies.

Ahearn, W.H., Castine, T., Nault, K., & Green, G. (2001). An assessment of food
acceptance in children with autism or pervasive developmental disorder - not otherwise specified. Journal of Autism and Developmental Disorders, 31, 505-512.

Feingold, B.F. (1975). Why your child is hyperactive. New York: Random House.

New York State Department of Health Early Intervention Program. (1999). Clinical
Practice Guideline: Report of the Recommendations. Autism/Pervasive Developmental Disorders, Assessment and Intervention for Young Children (Age 0-3 Years) (Publication No. 4215, pp. 163-194). Albany, NY: Author. (http://www.health.state.ny.us/nysdoh/eip/autism/index.htm#Table_of_Contents)

Reiten, D.J. (1987). Nutrition and developmental disabilities: Issues in chronic care. In E. Schopler & G.B. Mesibov (Eds.), Neurobiological issues in autism (pp.373-388). New York:Plenum

Potential Genetic Links to Autism

It has long been thought that genetic inheritance plays a significant role in autism. Several studies were conducted with fraternal and identical twins that revealed strong evidence that there is a genetic component to autism (see Folstein and Rosen-Sheidley, 2001 for a review of genetics and autism). The International Molecular Genetic Study of Autism Consortium (IMGSAC, 2001) recently completed a study in which one of two types of genetic testing was conducted with 152 pairs of siblings with autism. They reported that a portion of chromosome 2 was very strongly linked to the disorder while portions of two other chromosomes 7 and 16 were also identified as likely linkages. The goal of studying the genetics of autism is to come to a better understanding of what autism is and how it develops. Identifying particular genes that contribute to autism may lead to earlier and more accurate diagnoses.

Early identification of autism is of obvious importance and improvements in our understanding of the genetic makeup of autism will ultimately aid diagnosticians and clinicians. However, the identification of genes involved in autism is not likely to immediately translate into biologically based interventions. An NIH news release (NICHD, August 21, 2001) announcing the findings of the IMGSAC study notes that the wide range of symptoms displayed by the persons with autism may suggest that the disorder is a result of a “complex interaction between several different genes involved in brain signaling and development (and) (un)identified environmental factors are also likely to play a role.” Therefore, there is still much research to be done.

Folstein, S.E., & Rosen-Sheidley, B. (2001). Genetic of autism: Complex aetiology for a heterogeneous disorder. Nature Reviews: Genetics, 2(12), 943-955.

International Molecular Genetic Study of Autism Consortium (2001). A genomewide screen for autism: Strong evidence for linkage to chromosomes 2q, 7q, and 16p. American Journal of Human Genetics, 69, 570-581.

National Institute of Child Health and Human Development (2001, August 21). Researchers find new insights into the genetic foundations of autism. Retrieved August 21, 2001, from http://www.nichd.nih.gov/new/releases/genetics_in_autism.cfm.

Further evidence of secretin ineffectiveness as a treatment for autism

In a previous version of the NECC Research Newsletter (April-May 2001), the use of secretin as an intervention for autism was reported as an unproven treatment. Secretin is a hormone that exists naturally in the body and is involved in gastrointestinal functioning. It was reported in a medical journal that a single intravenous injection of secretin had resulted in substantial improvements in language and behavioral difficulties for three children diagnosed with autism. However, this was not a controlled study and the means of determining whether the injection had an effect was questionable. Strong scientific evidence has been growing that secretin has no clinically meaningful impact.

Several recent studies have confirmed secretin’s failure to improve skill performance or behavior problems and have addressed some of the criticisms of earlier investigations. One criticism of several controlled studies has been that the children injected with secretin have not had gastrointestinal problems. A study, conducted by scientists from Harvard University’s Medical School and the University of California, looked at children diagnosed with autism who were also reported to have gastrointestinal difficulties (Lightdale et al., 2001). They found that secretin produced no increases in language or other social skills and no decreases in problem behavior.

Another criticism has been that some children require multiple injections of secretin to show beneficial effects. A study by Roberts and colleagues (2001) investigated the effects of repeated injections of secretin relative to injections of a placebo with 64 children diagnosed with autism. They found no evidence that secretin was an effective treatment. They noted that both groups improved in receptive and expressive communication but that these gains “were likely attributable to familiarity with the testing situation, maturation, and/or ongoing behavioral interventions.” The study also found that the secretin injection was associated with: a rash for one child; a fever, rapid heartbeat, and vomiting for another child; an increase in irritability in 3 children; and, a flushing of the skin for 21% of the children who were injected with secretin.

Lightdale, J.R., Hayer, C., Duer, A., Lind-White, C., Jenkins, S., Siegel, B., Elliot, G.R., & Heyman, M.B. (2001). Effects of intravenous secretin on language and behavior of children with autism and gastrointestinal symptoms: A single-blinded, open-label pilot study. Pediatrics, 108(5). URL:http://www.pediatrics.org/cgi/content/full/108/5/e90.

Roberts, W., Weaver, L., Brian, J., Bryson, S., Emelianova, S., Griffiths, A., MacKinnon, B., Yim, C., Wolpin, J., & Koren, G. (2001). Repeated doses of porcine secretin in the treatment of autism: A randomized, placebo-controlled trial. Pediatrics, 107(5). URL:http://www.pediatrics.org/cgi/content/full/107/5/e71

Research at The New England Center

There have been several studies conducted at NECC that have been recently published or accepted for publication.

Editor’s note: Rumination is a potentially life-threatening condition in which food is regurgitated from the stomach to the mouth and either re-swallowed or expelled. The following study describes a treatment that was implemented to successfully treat a student’s rumination. Meals were followed by supplementary feedings of starchy foods.

Dudley, L.L., Johnson, C., and Barnes, R.S. (2002). Decreasing rumination using a starchy food satiation procedure. Behavioral Interventions, 17, 21-29.

A starchy food satiation procedure was evaluated in an ABAB withdrawal design on the post-meal rumination of a nine-year-old girl with autism. During treatment unlimited quantities of starchy foods were provided following each meal. High rates of rumination occurred during baseline conditions, followed by an immediate decrease in rumination during treatment. Rumination decreased to 82 and 97% of baseline during the first and second treatment conditions, respectively. In addition, follow-up probes were conducted at irregular intervals for 4 years following treatment, during which zero or near-zero rates of rumination were sustained. This study extends the literature on the functional relation between increased starchy food quantity and rumination in adults to rumination with a young child, and demonstrates maintenance of the treatment effect for 4 years.

Web Resources

For information about autism, visit the National Library of Medicine’s autism site www.nlm.nih.gov/medlineplus/autism.html.

For information about applied behavior analysis in the treatment for autism visit www.behavior.org.

For science-based information on biomedical treatments and theories in autism visit www.autism-biomed.org.

For professionally screened information on health care (including some treatments for autism and other developmental disabilities), visit www.quackwatch.com.




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