Diet Therapy in the Treatment of Autism

 In Autoimmune/Allergy Medicine, Pediatrics

Anita Bratt, BSc, ND

The treatment of Autism Spectrum Disorder (ASD) can be a challenging, prolonged and complicated process. It can also be extraordinarily rewarding when children begin to emerge from behind the autistic symptoms and engage in the world around them. Proper nutrition has been found to be one of the most successful interventions in treatment. Reports based on parental and clinical observations, as well as supporting research, have shown the benefits of numerous dietary protocols for autism. These include the gluten-free and casein-free diet, food allergy avoidance, anti-yeast diet, low-oxalate diet, phenol-restricted diet and specific-carbohydrate diet.

Gluten-Free and Casein-Free Diet

A cornerstone of autism dietary treatment has been the gluten-free and casein-free (GFCF) diet. The theory behind this approach is a hypothesized genetically-based peptidase deficiency, specifically diaminopeptidase IV. The enzyme is either genetically missing or inactivated due to an autoimmune mechanism. This results in improper digestion of gluten and casein proteins and formation of the opioid-like peptides casomorphin and gliadorphin (Reichelt and Knivsberg, 2003). These peptides enter the bloodstream across the “leaky gut” commonly found in ASD kids due to many factors, including food IgG sensitivities, microbial overgrowth and gastrointestinal inflammation. Once in the circulation, the casomorphin and gliadorphin compounds cross the inflamed blood-brain barrier and attach to opiate receptors in the brain (Shattock et al., 1990). Symptoms such as insensitivity to pain, decreased awareness of the environment and general “spaciness” result. These opioid peptides act as a drug, interfering with motivation, emotions, perception, responses and brain development (McCandless, 2003). Gluten and casein are shown to be highly immune-reactive, with anti-casein and anti-gliadin antibodies present in children with autism (Vojdani, 2003).

When implementing this diet, it is suggested to discontinue dairy for the first month, then gradually decrease gluten the following month to wean the child slowly from preferred foods and decrease the likelihood of extreme withdrawal reactions. It is recommended to strictly adhere to the diet for three to six months because proteins, especially gluten, can take several months to be removed from the body. Children with this sensitivity frequently crave the dairy and gluten foods intensely and self-restrict their diets. They often go through a withdrawal period for several months much like an addict would, with increased severity of behaviors, refusal to eat alternative foods, tantrums and insomnia.

Typical beneficial responses include increased awareness of and engagement and responsiveness to their environment, with language improvements, decreased self-stimulatory behaviors, improved eye contact and increased cognition. Often, parents will report that their child has “come back to them” and is no longer in his or her own world. Positive responses are seen in approximately 65% (range of 50%-80%) of children put on this diet (Baker and Pangborn, 2005). Clinically, I have found this to be the single most effective intervention, and I always recommend that parents try it at the start of treatment.

One successful example: A 2-1/2-year-old boy with ASD had dramatically improved eye contact, cessation of daily tantrums, increased responsiveness to communication, elimination of hyperactivity and decreased hand-flapping behavior after one month on the GFCF diet.

Those who do not adhere to the diet do not respond as well to other therapeutics or make the same improvements in neurological symptoms compared to those on the GFCF diet (Knivsberg et al., 2001).

A gluten and casein peptide test, which measures urinary excretion of gliadorphin and casomorphin, helps to refine the diet by differentiating those children who may be more sensitive to either gluten or casein. The addition of specific digestive enzyme formulations containing the diaminopeptidase IV enzyme can also be of aid on a GFCF diet when dietary infractions occur, as they can alleviate or prevent a flare-up of symptoms due to gluten or casein reactions.

Food Allergy Avoidance

An important step in the ASD dietary protocol is to address problematic foods that may be causing inflammation. One method of evaluation is an IgG food allergy test, recommended at the outset of therapy to identify possible delayed food sensitivity reactions. Eliminating moderate to highly reactive foods can improve autistic symptoms especially related to digestive and behavioral problems. Studies have consistently found significantly elevated antibodies to food antigens in autistic children and higher levels of proinflammatory cytokines in food protein challenges (Jyonouchi et al., 2002). More non-IgE mediated food allergies are also associated with ileal lymphoid hyperplasia, found in children with autism (Wakefield, 2000). I treated one child who would hide under a table and growl every time he was upset. The behavior disappeared when he stopped eating eggs, which came up extremely high on his IgG food panel.

Common autistic symptoms that improve with food allergy elimination diets are head-banging; self-stimulatory behaviors (or “stimming”) such as hand flapping; sleep disturbances (frequent waking, nighttime screaming); self-injurious behaviors; and aggression. Often, chronic issues such as constipation, diarrhea and dermatitis resolve. A trial elimination for at least one month followed by a food challenge can be useful if obvious benefits are not seen initially. The most common allergens noted in children with autism are dairy, gluten, wheat, soy, eggs, corn and peanuts.

Anti-Yeast Diet

The anti-yeast or Candida diet is often necessary in ASD children due to intestinal yeast overgrowth, as noted on urine organic acid testing, stool analysis, or clinical history and symptoms. Restriction of sugars, yeast, fermented and mold products with the addition of supplemental probiotics and anti-fungals are necessary to treat this often chronic issue. Children on the autism spectrum with yeast typically exhibit telltale behaviors: excessive stimming (both vocal and physical), cravings for high-sugar foods, giddiness, inappropriate laughter, spaciness or “drunk” behavior with loss of balance. Accompanying symptoms may also be present, including excessive gas, bloating, constipation or diarrhea, and dermatitis. Introduction of this diet typically occurs with or just following GFCF diet implementation when fungal dysbiosis is evident in the autistic child.

A three-year-old boy in my practice with ASD and seizure disorder responded remarkably to dietary intervention. At the outset of treatment he was non-verbal and experienced ten seizures per day on average despite anti-convulsant medication. After one month on the GFCF diet, he experienced only three to four seizures a day, and with subsequent anti-yeast therapy for three months, he became seizure-free and began speaking.

Low-Oxalate Diet

The low-oxalate diet was developed after discovering that a significant number of autistic children have excessive urine oxalate levels, with possible accumulation of oxalates in various body organs, including the gastrointestinal tract, brain, blood-brain barrier, skin, heart, tendons, kidney, bone and eyes (Shaw, 2007). In addition, oxalates are known to bind with heavy metals, forming complexes that are deposited in body tissues. Pockets of oxalate crystals can damage tissue, cause oxidation and lead to diverse symptoms such as digestive pain, toe walking, eye poking, white skin lesions, discomfort on urination, excessive urinary frequency, enuresis, cloudy urine, genital discomfort and rubbing, and “sandy” stools. Restriction of high oxalate foods such as spinach, soy, peanuts, chocolate and berries has been found to be beneficial in these cases. Limiting total dietary oxalate intake to less than 50mg per day is recommended. Reducing vitamin C-rich foods or supplements is not necessary in the presence of high urinary oxalic acid unless there is increased free copper or iron to act as oxidative catalysts for the formation of oxalate via ascorbate (Shaw, 2007). High urinary oxalic acid levels are often found in conjunction with elevated yeast, as Candida can induce oxalate formation; therefore, an anti-yeast protocol is suggested when oxalate values are raised. In addition, supplementation with taurine and calcium citrate helps to reduce oxalate absorption in the digestive tract.

Phenol-Restricted Diet

Impaired sulfation capacity is documented in autism, with some children displaying sensitivity to phenolic amines in foods due to deficient function of the phenol sulfotransferase (PST) enzyme (Waring, 2000). For this subset, restriction of high-phenol foods may be beneficial, which includes bananas, chocolate, cheese, apples, grapes and tomatoes. The phenol-sensitive ASD child will exhibit abnormal behaviors such as hyperactivity, and red face and ears after consuming these foods. The PST enzyme is also responsible for metabolism of amine neurotransmitters like dopamine and epinephrine, which are often dysfunctional in autism. As with the previous dietary interventions, a trial of elimination then re-challenge of the suspected offending foods can aid in determining whether it may be a beneficial therapy. In addition to the dietary recommendations, adding an enzyme supplement containing xylanase specific for phenol digestion can reduce symptoms.

Specific-Carbohydrate Diet (SCD)

The newest diet is the SCD, originally proposed as a therapeutic diet for inflammatory bowel disease. By restricting foods contributing to intestinal dysbiosis, the goal of this intervention is to starve pathogenic microorganisms and reduce inflammation in the gastrointestinal tract. The SCD limits complex carbohydrates, particularly disaccharides, relying on protein, fats and simple carbohydrates to heal the gut. Abnormal carbohydrate digestive enzyme activity has been found in almost 60% of ASD children studied (Horvath et al., 1999). Partially digested sugars or starches cause inflammation, dysbiosis and excessive mucus production, and can promote leaky gut syndrome.

Many children who do not respond well to previous diet protocols often benefit from the SCD, especially those ASD children with significant chronic digestive problems. I treated three siblings with autism who previously tried the GFCF and food allergy avoidance diets with limited success. All responded remarkably to the SCD. Their chronic diarrhea resolved, and behavior changes were significant, including improved communication, decreased tantrums, more emotional regulation, better sleep, less hand flapping and improved eye contact. According to a parent-report survey, 69% of children on average improved on the SCD more than with any other autism dietary protocol (Baker and Pangborn, 2005).

It is important for the health and healing of children with autism to implement specific dietary changes determined by individual needs and responses. Nutritional therapy has the capacity to make significant, long-lasting changes in the abnormal biochemistry, as well as the physical and behavioral expression of ASD. Addressing dietary factors must be a key component of any treatment plan for a child on the autism spectrum.

brattAnita Bratt, BSc, ND has a family practice focusing on ASD and ADHD/ADD. She attended NCNM and Bastyr University before graduating from the Boucher Institute of Naturopathic Medicine. Dr. Bratt has a 12-year old autistic son, and held the first outreach clinic for autism and ADHD in Western Canada in March 2007. She currently practices in Vancouver, B.C.



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McCandless J: Children with Starving Brains: A Medical Treatment Guide for Autism Spectrum Disorder (2nd ed). Putney, 2003, Bramble Books.

Vojdani A et al: Infections, toxic chemicals and dietary peptide binding to lymphocyte receptors and tissue enzymes are major instigators of autoimmunity in autism, Int J Immunopathol Pharmacol Sep-Dec;16(3):189-199, 2003.

Baker S and Pangborn J: Autism: Effective Biomedical Treatments (2nd ed). San Diego, Sept. 2005, Autism Research Institute.

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Jyonouchi H et al: Innate immunity associated with inflammatory responses and cytokine production against common dietary proteins in patients with autism spectrum disorder, Neuropsychobiology 46(2):76-84, 2002.

Wakefield AJ et al: Enterocolitis in children with developmental disorders, Am J Gastroenterol Sep;95(9):2285-2295, 2000.

Shaw W: Oxalates: An important etiological factor in the diagnosis and treatment of autism. Presented at Great Plains Laboratory physician training seminar, March 2007.

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