Survey Points to Diet Research
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Research Update: Survey Analysis of Gluten and Casein Free Diet in ASD Population

March 29, 2012 - News and Notes from The Johnson Center

Surveys are used to gather information such as current opinions on political issues or on the latest summer movies. Though not a true experiment, a survey is a useful research tool for determining behaviors, attitudes, and beliefs. However, individual surveys rarely provide strong evidence of cause and effect. In the latest study on ASD and GFCF diets published in Nutritional Neuroscience, researchers relied on parental report survey data to identify what is believed about elimination diets in relation to behavior and health. The authors of the study concluded that parents who were the most rigorous in administering a GFCF diet to their children are more likely to report improvements in health and ASD and social behaviors.

Penn State scientists developed a 90-item questionnaire for 387 caregivers to answer concerning their child’s health and diet. This questionnaire covered gastrointestinal (GI) symptoms, food allergies and sensitivities, and compliance and length of GFCF diet trial. Analysis of the survey responses revealed a statistically strong positive correlation between diet adherence and improvement in health (i.e. rash, constipation, diarrhea and seizures), ASD behaviors (i.e. stimming, hyperactivity, sensory seeking, tantrums, and echolalia), and social behaviors (i.e. responsiveness, eye contact, attention span and language production). To put it another way, children following a less strict GFCF diet reported less improvement. Also, more children fared better when following the GFCF diet for at least six months.

Though the findings of the study are compelling, the results should be interpreted cautiously; the effect of bias in responses to the questionnaire needs to be considered. A parent’s perception of his or her child’s health and well-being is not subject to objective scrutiny in this study. Researchers did not verify diagnoses, medical records, or food diaries of the children in question. 92.7% of children had a reported history of GI symptoms and 93.4% had reported food allergy symptoms. With such minimal diversity in the group, it is difficult to forecast if similar improvements in behavior would be seen in healthy ASD children. It is also worth noting that the questionnaire did not enquire about other interventions, either medical or behavioral, that could have contributed to the increased reports of diet-derived benefit.

As is true for all surveys, conclusions are drawn from report and not observation or true experiment. Researchers correctly admit that their findings should be experimentally investigated. The study by design failed to provide direct evidence of GFCF diets causing physiological or psychological improvement in ASD children, but provided useful insight in the role of therapeutic diets in the treatment of autism. Preliminary data presented in the research article are helpful for future research projects as they highlight areas requiring further study.


Journal Reference:
Pennesi Christine M.; Klein Laura Cousino. Effectiveness of the gluten-free, casein-free diet for children diagnosed with autism spectrum disorder: Based on parental report. Nutritional Neuroscience, 2012 DOI: 10.1179/1476830512Y.0000000003