Debunking the Myth of GFCF Diets Improving Autism Symptoms

Some individuals within the autism community have suspected that food additives and diet have negatively affected children who have a developmental disorder characterized by communication and social deficits. The term autism diet or GFCF refers to a diet that is free of products that contain gluten, which is a protein composite found in grains such as rye, wheat and barley as well as casein, which is a protein found in milk. For years, this special diet has been used as an alternative treatment for children with autism; however, according to a recent study, an autism diet does not improve the symptoms or behaviors related to any of the autism spectrum disorders(ASD). Furthermore, researchers state that placing a child on a GFCF diet and using supplements as a substitute for actual food can be harmful to his or her health.

Autism Diets Are an Ineffective Form of Treatment

The Gluten-Free/Casein-Free Diet: A Double-Blind Challenge Trial in Children with Autism that is published in the Journal of Autism and Developmental Disorders (January 2016, Volume 46, Issue 1) states that GFCF diets are ineffective; whereas, the Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive, that is published in the Journal of the Academy of Nutrition and Dietetics (August 2015, Volume 115, Issue 8) states that autism diets can be harmful to the children whose diets are being restricted.

Susan L. Hyman, M.D., chief of the Division of Neurodevelopmental & Behavioral Pediatrics at theUniversity of Rochester Medical Center (URMC) was involved in both of the aforementioned studies: Hyman is the lead author of The Gluten-Free/Casein-Free Diet: A Double-Blind Challenge Trial in Children with Autism. She and her colleagues launched this study as a means to provide families information about the potential effect of dietary changes as a treatment for ASD.

Hyman states that autism diets have been popular for years; however, there is no evidence that these diets are effective in treating ASD. She continues, stating there are also concerns that the families trying these gluten-free/casein-free diets may implement them without assistance from a dietician. Although a diet free of casein and gluten may be able to meet the nutritional needs of the child, families may find it beneficial to attain professional advice to ensure their children receive an adequate amount of vitamins and nutrients, such as vitamin D and calcium.

Gluten-Free/Casein-Free Diet: A Double-Blind Challenge Trial in Children with Autism – The Study

Hyman and a group of her colleagues conducted this study to test whether the GFCF diet had any benefits for children who had already received an ASD diagnosis.

The Participants

Although researchers started with 22 participants, persuading families to get involved was challenging and several families discontinued participating in the study because their children were unhappy with the diet; however, there were 14 participants who completed the study, their ages ranged between 3 to 5 years. Throughout the study, the participants’ families worked with a registered dietician to ensure the children received adequate nutrition while they were on the gluten and casein free diet. This study lasted for 30 weeks.

The Autism Diet is Implemented

For the initial four to six weeks parents implemented a gluten-free/casein-free diet and a behavioral intervention program.

The Weekly Food Challenge – Blinded Distribution

Once the children became accustomed to their new diets, they were challenged with a food that contained casein, gluten, both casein and gluten or just a placebo. Throughout this study, none of the parents, administrating researchers or children knew which children received an actual food challenge or a placebo. This food challenge was performed every week for a total of 12 weeks.

Creating The Foods

In the kitchen at the university clinical research center, the researchers themselves carefully created foods that contained gluten and casein as well as foods that did not. The with and without foods the researchers created resembled each other so closely (in texture and in taste) that the children did not notice any differences. The foods that contained gluten had the equivalent found in two chocolate-chip cookies; while, the casein totaled the amount found in a half a cup of milk.


Following each food challenge, the scientists documented the behavior of the participants while they remained in the lab; however, parents were asked to continue monitoring their children at home. The researchers asked parents to note changes in sleep patterns, autism symptoms (in general) and bowel movements.

The Results

By the end of the study, each participant had received three placebo snacks, three snacks containing gluten, three snacks containing casein and three snacks that contained both gluten and casein. The data gathered throughout the study shows no significant change in the outcomes between when children consumed foods that contained casein, gluten, both casein and gluten or the placebo food. For this reason, Hyman states that there is no evidence that a GFCF diet improves the symptoms that the study measured in young children with an ASD; however, she does recommend investigating other aspects of nutrition. Furthermore, one of the biggest concerns experts have related to the autism diet is whether the child receives all the nutrients he or she needs.


Dietary Supplementation in Children with Autism Spectrum Disorders: Common, Insufficient, and Excessive – The Study

Research indicates that an autism diet can lead to a child having either an insufficient amount of or an excessive amount of nutrients: And both of these circumstances can be harmful to his or her health.

The Participants

At New York’s University of Rochester Medical Center, 368 children were recruited to participate inthe study. The children’s ages ranged between 2 and 11 years. All participants had already received a diagnosis of an ASD.

Caregiver Training

Each participant’s caregiver received training from a registered dietician nutritionist as to the proper method for recording the beverages, food and supplements the participant consumed.


Once training was complete, each participant’s caregiver was asked to keep track of everything the participant consumed for the following three days. The documented information needed to include supplements (their brand names), pictures of food labels and any recipes used to prepare food.

The Results

Upon examining the participants’ eating records, investigators realized that when compared to typically developing children, the children with ASD consumed a comparable amount of micronutrients. Furthermore, both groups of children had deficiencies in  vitamins E and D as well as in potassium, calcium, and choline. For this study, 56 percent of the children with an autism spectrum disorder received supplements; however, even after receiving supplements, 30 to 40 percent of the children with ASD were lacking vitamin D and anywhere from 40 to 55 percent had an insufficient supply of calcium.

The Breakdown

Children with an autism spectrum disorder who were on the GFCF diet consumed more vitamin E and magnesium that those who were not. Moreover, children on the autism diet received adequate vitamin D supplementation; however, calcium was inadequate for children who were on the gluten and casein-free diet as well as for those who were not.

Despite varying eating behaviors, the children who had ASD received the majority of their micro-nutrients from the food they ate, possibly, due to the addition of vitamins and minerals to the modern food supply; however, these additional vitamins may also be problematic in that many of the children with ASD who participated in this study and took supplements surpassed the Tolerable Upper Limit levels for the safe intake of zinc, vitamin A and folic acid.

Trina McMillin

Trina brings to Relias a wealth of knowledge and personal experience related to the medical field, dental issues, mental health, and physical therapy techniques. She has worked in various positions over her career which includes being a phlebotomist, laboratory assistant and medical transcriptionist.

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