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Publication #FCS8991

Autism Spectrum Disorder and Diet1

Michelle A. Zitt, Karla P. Shelnutt, and Gail P. A. Kauwell2

Figure 1. 

Scientists have begun to research the effects of diet on ASD, but to date no one dietary approach has been found to significantly improve ASD symptoms.


miketually (CC BY 2.0)

[Click thumbnail to enlarge.]

As the caregiver of a child with Autism Spectrum Disorder (ASD), the search for answers about your child’s condition may seem endless. Doctors and scientists are working hard to understand the nature of ASD, but there is much work left to be done. Nutrition and diet may affect ASD children in ways that are different from children who do not have ASD. There are thousands of Internet sites about ASD and diet, but much of the information has no scientific proof. Some caregivers, desperate to help their child, have tested different diets with the hope that they will see improvement in ASD symptoms. If you are considering making changes to your child’s diet, the information in this publication will help you to understand the potential risks and benefits of these changes.

Autism Spectrum Disorder

Autism Spectrum Disorder is a term that describes a number of disorders that vary based on severity. Many theories exist about the causes of ASD, but none has enough proof to support their claims. Your ASD child may show traits such as delayed speech, difficulty with non-verbal communication skills, discomfort in social settings, and obsessive, repetitive behavior patterns. He or she also may have a very sensitive sense of taste, touch and smell. Chronic gastrointestinal (GI) problems and intolerances to certain foods are also common features of ASD. These conditions can range from mild to severe, so children with ASD should be treated on a case-by-case basis.

ASD is a fairly new diagnosis, and much about these disorders is still unknown. ASD is thought to be a genetic trait, but the exact cause is still a mystery. Since ASD includes a wide range of characteristics and symptoms, it is challenging for researchers to pinpoint a single genetic source. Some scientists believe that environmental factors may play a role in causing ASD, but this has not been supported by research. Due to the results of one discredited study that became popularized in the media, many people believe that childhood vaccines cause ASD. Many scientists have published results of valid research proving vaccines to be safe.

Standard therapies such as speech therapy, occupational therapy and physical therapy address the behavioral issues of ASD. Parents and caregivers can be trained to encourage positive behaviors when dealing with challenges such as outbursts and disturbing conduct. Various dietary changes have been suggested as a way to improve symptoms associated with ASD, but none is well supported by research. In spite of this, personal accounts of the positive effects of diet on ASD symptoms have inspired many caregivers to experiment with the diet of their ASD children. Scientists have begun to research the effects of diet on ASD, but to date no one dietary approach has been found to significantly improve ASD symptoms.

Dietary Issues

Diet and nutrition can impact your ASD child in many ways. You might find that she is sensitive to the taste, touch, and smell of food. This is very common in ASD children and can result in pickiness when it comes to eating. Because of this sensitivity, she might not like the texture of some foods and may reject them. Your ASD child might even limit her intake to only a few foods. When facing these challenges, it may seem impossible to provide good nutrition for your child.

How can I get my child to eat more foods?

There are strategies that you can use to guide your child toward more food options. For example, if you present food in a way that appeals to your ASD child, it may give him a more positive feeling about eating it. This may mean arranging foods in a specific way on the plate, or offering the food in different forms, such as raw, baked, steamed, pureed, or cooked. Another option is to offer dips and sauces that he already enjoys along with a food that is not familiar or preferred. Try introducing new foods that are similar in some way to foods that your child already likes. For example, if he likes strawberry ice cream, you could offer a smoothie made with real strawberries and low-fat yogurt. You can use the foods that your child likes as a guide toward other healthy options that are similar in flavor, color, or texture.

Figure 2. 

Try introducing new foods that are similar in some way to foods that your child already likes. For example, if your child likes strawberry ice cream, you could offer a smoothie made with real strawberries and low-fat yogurt.


joyosity (CC BY 2.0); sigurdas (CC BY-SA 3.0)

[Click thumbnail to enlarge.]

It may take time, patience, and frequent exposure to the same food before your child accepts or grows fond of a food. Remember to allow her to get used to new foods in stages. The first stage might be to look at or touch a new food. Seeing, smelling, and feeling the food might make her more comfortable with the idea of tasting it too. It is important not to become frustrated. Creating a power struggle with your child will only make things worse, and you and your child will end up even more frustrated.

What if my child has gastrointestinal issues?

GI problems such as chronic stomach pain, constipation, diarrhea, gas, and reflux are common in ASD children. While scientists debate the causes, caregivers need to find ways to manage their children’s symptoms. If your ASD child is able to communicate well, he may be able to tell you when he feels sick. If he has trouble expressing himself, his symptoms might lead to changes in behavior. Signs that suggest your child may not feel well include sleep disturbance and aggression. Your child also might hold or point to his stomach more often. If you think your child has GI problems, consult your doctor so that you can discuss tests and treatment options.

Food Intolerances

A food intolerance is a negative reaction to a normal food. Food intolerances often result in stomach pain, bloating, and/or diarrhea. It is important to note that a food intolerance is not the same as a food allergy—a food allergy causes a more extreme reaction from the body’s immune system that could even result in death; a food intolerance is solely a digestive system response.

Some scientists believe that chronic GI tract symptoms among ASD children are caused by food intolerances and abnormal digestion. The theory is that the intestines of ASD children do not function normally. The incomplete breakdown of certain proteins causes abnormal substances to form that enter the blood stream. It is possible that certain behaviors observed in ASD children may be caused by these substances entering the brain. This is basis for ASD diets that eliminate foods that are not well tolerated.

How do I know if my child has an intolerance?

If you suspect that your child has a food intolerance, it is important to discuss this with your doctor who may recommend removing certain foods from your child’s diet. First, your doctor or a registered dietitian nutritionist might ask you to keep a detailed log of the foods that your child eats for a certain period of time. With this information, he or she can try to narrow down which food or foods might be causing the problem. After target foods are identified, they are removed from the diet one at a time, and changes in symptoms are analyzed. You might find that many of the tested foods were not the problem. If this happens, you can move on to another target food and try again. This can be a long process, but it can have positive results.

Figure 3. 

Your doctor or a registered dietitian nutritionist might ask you to keep a detailed log of the foods that your child eats for a certain period of time.


Jack Hollingsworth/Photodisc/

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Gluten-Free and Casein-Free Diet

What are gluten and casein?

  • Gluten is a protein in wheat, barley and rye.

  • Casein is a protein in dairy products.

The gluten-free and casein-free diet (GFCF diet) is one of the most common diet approaches parents use for their ASD children. The GFCF diet is free of all products that contain gluten and/or casein.

Use of the GFCF diet to treat ASD is based on the food intolerance theory. Although many parents are hopeful that these dietary changes will lead to improvements in ASD symptoms, more research is needed to determine whether the GFCF diet is effective.

If you would like to put your child on the GFCF diet, there are some things that you should know. First, this diet has not been proven to be a safe and effective treatment for ASD. Second, since gluten and casein are very common in the typical American diet, it is difficult to remove them from your child’s diet. These proteins are found in many processed foods and are listed on nutrition labels under several different names. New labeling laws make it easier to identify foods with gluten, but you need to look carefully at nutrition labels to tell if the food has casein. For more information about reading labels, see the USDA’s Food Allergies and Intolerances Resource List for Consumers at

There are several potential drawbacks to the GFCF diet including the extra cost for gluten-free foods and extra time that may be required for preparing meals. The GFCF diet also may make it difficult to eat away from home. If your child is placed on this diet, you will need to talk to friends and family members who may feed her. In addition, you will need to discuss the diet change with your child’s school. Before starting this diet, it is best to discuss your plans with your doctor and a registered dietitian nutritionist to be sure that your child is getting the right nutrition for normal growth and development.


Some research suggests that using certain nutritional supplements may reduce ASD symptoms. More research is needed to determine if these supplements are effective. Many vitamins and other nutrients have been tested as treatment options, but their use is not supported by scientific evidence. Some vitamins and minerals can be harmful when taken in large doses, so use caution if you plan to add them to your child’s diet. Again, before making these changes to your child’s diet, consult your doctor and a registered nutritionist. They can work with you to make sure that your child will not be at risk for negative reactions or overdoses.

Children with ASD often are picky eaters and may limit their intake to only a few types of foods. For this reason, parents may decide to use vitamin/mineral supplements to fill in the gaps. They also may believe that supplements will improve their child’s symptoms. Unfortunately, supplementation is unlikely to result in major changes in symptoms, and may even lead to excessive intake of some nutrients and still not meet the need for other nutrients like calcium and vitamin D. The best way to know if your child may benefit from a vitamin/mineral supplement is to work with your doctor and a registered dietitian nutritionist to assess your child’s intake and needs. This can help to ensure that he is getting the vitamins and minerals he needs without getting too much.

Issues with Special Diets

Several issues can arise when trying to change your child’s diet. The picky-eating habits your ASD child might have may make dietary changes difficult. Special diets also can be costly and inconvenient, so it is important to assess if the changes would fit into your life and budget. While many parents claim that a certain diet worked for their ASD child, you might find that your child does not experience the same results. Testing different diets and supplements takes time and considerable effort, and it really is best to discuss changes with your doctor and a registered dietitian nutritionist to make sure that your child is getting the right nutrition.

Things to Consider

  • Talk to your doctor and a registered dietitian nutritionist.

  • Discuss diet changes with school staff and other caregivers.

  • Consider the time, effort, and money involved with trying different diets.

The Bottom Line

It is natural for you to be eager to find ways to improve your child’s ASD symptoms. But before making any changes, consider the advice of your doctor and a registered dietitian nutritionist and evaluate what is best for your child and your personal situation. Even if you do not plan to try any of these dietary treatments, focusing on nutrition is still important.

Learn More

To learn more about nutrition options for your ASD child, use the resources listed below:

  • Cooperative Extension Family and Consumer Sciences (FCS) Educator (look in the blue pages of your telephone book). Florida Extension offices are listed online by UF/IFAS at or

  • For referral to a registered dietitian nutritionist (RDN) in your area you can call the Florida Academy of Nutrition and Dietetics at (850) 386-8850 or check the yellow pages of your phone book. You can also find a registered dietitian nutritionist in your area by visiting the Academy of Nutrition and Dietetics RD Finder at

Recommended Websites


Buie, T., Fuchs, G. J., Futura, G. T., Kooros, K., Levy, J., Lewis, J. D., Wershil, B. K., & Winter, H. (2010). Recommendations for evaluation and treatment of common gastrointestinal problems in children with ASDs. Pediatrics, 125, S19–S29.

Cermack, S. A., Curtin, C., & Bandini, L. G. (2010). Food selectivity and sensory sensitivity in children with autism spectrum disorders. J Am Diet Assoc, 110, 238–246.

Levy, S. E., & Hyman, S. L. (2005). Novel Treatments for Autistic Spectrum Disorders. Ment Retard Dev Disabil Res Rev, 11, 131–142.

Elder, J. H. (2008). The gluten-free, casein-free diet in autism: An overview with clinical implications. Nutr Clin Pract, 23, 583.

Marcason, W. (2009). What is the current status of research concerning use of a gluten-free, casein-free diet for children diagnosed with autism? J Am Diet Assoc, 109, 572.

Stewart, P. A., Hyman, S. L., Schmidt, B. L., Macklin, E. A., Reynolds, A., Johnson, C. R., James, S. J., & Manning-Courtney, P. (2015, in press). Dietary supplementation in children with autism spectrum disorders: common, insufficient, and excessive. J Acad Nutr Diet. DOI:



This document is FCS8991, one of a series of the Department of Family, Youth, and Community Sciences, UF/IFAS Extension. Original publication date September 2011. Revised July 2015. Visit the EDIS website at


Michelle A. Zitt, MS, RDN (UF Dietetic Internship Program alumna, 2012); Karla P. Shelnutt, PhD, RDN, assistant professor, Department of Family, Youth, and Community Sciences; and Gail P. A. Kauwell, PhD, RDN, LD/N, professor, Food Science and Human Nutrition Department; UF/IFAS Extension Gainesville, FL 32611.

The Institute of Food and Agricultural Sciences (IFAS) is an Equal Opportunity Institution authorized to provide research, educational information and other services only to individuals and institutions that function with non-discrimination with respect to race, creed, color, religion, age, disability, sex, sexual orientation, marital status, national origin, political opinions or affiliations. For more information on obtaining other UF/IFAS Extension publications, contact your county's UF/IFAS Extension office.

U.S. Department of Agriculture, UF/IFAS Extension Service, University of Florida, IFAS, Florida A & M University Cooperative Extension Program, and Boards of County Commissioners Cooperating. Nick T. Place, dean for UF/IFAS Extension.