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Special Diets and Autism Ranking: Unable to rate

Vegetables

Special diets are diets which have been modified in some way to bring about specific healthcare benefits. Most special diets used to help autistic people are ‘exclusion’ diets. This means you avoid or reduce foodstuffs which may harm you (such as additives in the additive-free diet). Other examples of exclusion diets are the gluten-free, casein-free diet, and the salicylate-free diet.

In some diets you have to exclude some foodstuffs but include others, such as the specific carbohydrate diet. This excludes complex carbohydrates (such as those found in rice and potatoes) and replaces them with simple carbohydrates (such as those found in bananas and squashes).

In practice, many diets share similar characteristics. For example, the Feingold diet is a mixture of the additive-free diet and the salicylate-free diet, while the specific carbohydrate diet incorporates elements of the gluten-free diet.

Some people think that diet is a key component of any intervention designed to help autistic people. Some people also think that modifying the diet and the gastrointestinal system is necessary for the success of other treatments and therefore should come first.

Diets are sometimes combined with other therapies. For example, some people advocate following a particular diet, taking one or more dietary supplements and using detoxification techniques such as chelation.

Please note

The National Institute for Health and Care Excellence (2012) made the following observations on the use of exclusion diets for autistic adults:

‘... there is very little evidence regarding safety and efficacy for exclusion diets ... for the treatment of autism.’

The National Institute for Health and Care Excellence (2013) made the following observations on the use of exclusion diets for autistic children and young people:

“Do not use the following interventions for the management of core features of autism in children and young people: exclusion diets (such as gluten- or casein-free diets).”

Our Opinion

Eating a healthy balanced diet is recommended for everybody in order to maintain good health. Anyone with a particular condition (in addition to or separate from autism) may be recommended to follow a special diet by a dietitian and this should be followed on an individual basis. For example, dietitians may recommend a gluten or milk exclusion diet for various gut problems.

Most special diets provide the same benefits for autistic people as they do to people who are not autistic. They do not appear to provide any additional benefits to autistic people, according to a limited amount of research evidence of sufficiently high quality.

No evidence at all supports the use of most special diets (such as additive-free diets, the specific-carbohydrate diet, and the yeast-free diet).

Determining the benefits of other diets (such as the gluten-free, casein-free diet or the ketogenic diet) for autistic people is not currently possible. We must wait until further research of sufficiently high quality has been completed.

We believe that some special diets (such as the Gut and Psychology Syndrome Diet) are scientifically unfeasible and potentially very harmful. For this reason, we strongly recommend that they are not used. Because diets for people with autism constitute such a wide range of treatments it is not possible to provide a ranking for diets as a whole.

Disclaimer

Please read our Disclaimer on Autism Interventions


Audience

Some special diets may be recommended for people with specific health problems and/or nutritional requirements. For example,

  • According to the Feingold Association of the United States website, accessed on 27 September 2016, the Feingold diet may be appropriate for a wide range of people including those with health, learning and behaviour problems such as short attention spans, cognitive and perceptual disturbances, emotional concerns, neuro-muscular difficulties etc.
  • Gluten-free diets are recommended for people with coeliac disease and gluten hypersensitivity (allergy or  intolerance).  Milk-free diets are recommended for people with milk hypersensitivity.
  • According to Castro et al (2015), “The ketogenic diet may be recommended for people with epilepsy who have not responded to conventional anticonvulsant treatments, such as anticonvulsant medications. It has also been suggested as a treatment for Alzheimer’s disease, migraine, Parkinson’s disease and depression.”
  • According to Zelman (2011), the specific carbohydrate diet may be recommended for people with a variety of gastrointestinal problems including Crohn’s disease, ulcerative colitis, coeliac disease, irritable bowel disease and irritable bowel syndrome.

Aims and Claims

Aims

All special diets are diets which have been modified in some way to bring about specific healthcare benefits.  For example,

  • The Feingold Diet is designed to determine if certain foods or food additives are triggering particular symptoms, such as hyperactivity, and then to manage those symptoms.
  • The gluten-free casein-free diet is designed to eliminate or reduce harmful peptides (a type of protein) created when gluten and casein are broken down in the gut.
  • The ketogenic diet is a low-carbohydrate diet designed to mimic many of the biochemical changes associated with prolonged starvation, although it is not clear how the diet is supposed to work.
  • The specific carbohydrate diet is designed to promote normal gut functioning by removing complex carbohydrates which are supposed to feed harmful fungi and bacteria.

Claims

There have been various claims for different special diets. For example,

  • According to the Feingold Association of the United States website, accessed on 27 September 2016, the Feingold Program can bring about a range of improvements. For example, it may help with problems such as short attention spans, cognitive and perceptual disturbances, emotional concerns, neuro-muscular difficulties etc.
  • According to Knivsberg et al (2002) “Children on a gluten and casein free diet had statistically significant reductions in aloofness, routines and rituals, and improvements in responses to learning, as well as various social and emotional and communication measures.”
  • According to Castro et al (2015), “Upon completion of the [ketogenic diet], patients presented ameliorated behavioural symptoms, which were reflected on improved scores in CARS [Childhood Autism Rating Scale], and a reduction in the number of seizures.”
  • According to the pecanbread.com website, accessed on 27 September 2016, “Children with autism who are implementing [the specific carbohydrate diet] are demonstrating remarkable improvements in bowel function, language, eye contact, self-stimulatory behavior, anxiety, and mood.”

Key Features

Special diets are diets which have been modified in some way to bring about specific healthcare benefits. Most special diets used to help autistic people are ‘exclusion’ diets. This means you avoid or reduce foodstuffs which may cause specific symptoms (such as additives in the additive-free diet). Other examples of exclusion diets are the gluten-free, casein-free diet, and the salicylate-free diet.

In some diets you have to exclude some foodstuffs but include others, such as the specific carbohydrate diet. This excludes complex carbohydrates (such as those found in rice and potatoes) and replaces them with simple carbohydrates (such as those found in bananas and squashes).

In practice, many diets share similar characteristics. For example, the Feingold diet is a mixture of the additive-free diet and the salicylate-free diet, while the specific carbohydrate diet incorporates elements of the gluten-free diet.

It is important to remember that small quantities of many ingredients such as wheat and milk are used in many different foods. For example, gluten or its derivatives can appear in a wide range of things including biscuits, nuggets and chips, as well as some flavourings.

Some people think that diet is a key component of any intervention designed to help autistic people. Some people also think that modifying the diet and the gastrointestinal system is necessary for the success of other treatments and therefore should come first.

Diets are sometimes combined with other therapies. For example, some people advocate following a particular diet, taking one or more dietary supplements and using detoxification techniques such as chelation.

Specific diets

The following is a list of some diets which have been reported to be beneficial to autistic people.

Many of these diets share similar characteristics. For example, the Feingold diet is a mixture of the additive-free diet and the salicylate-free diet, while the specific carbohydrate diet incorporates elements of the gluten-free diet.

  • Additive-free diet, also known as the chemical-free diet. Requires you to avoid additives, such as colourings, flavour enhancers, sweeteners and preservatives. Specific programmes which incorporate an additive-free diet include the Feingold Diet and the Special Foods Diet.
  • Allergy-free diet. Requires you to avoid those foodstuffs which have been shown to cause you allergies (the most common include gluten, dairy, cane sugar, corn, soy, yeast, peanuts, egg, artificial colours and preservatives).
  • Casein-free diet, also known as the dairy-free diet. Requires you to avoid all sources of casein, a protein found in many dairy products, such as milk, butter and yoghurt.  (In practice, there are numerous proteins other than casein in dairy products that some people may react to.)
  • Detox diet. Also known as the detoxification diet or the natural diet. Requires you to avoid processed foods, to eat fresh, organic food and, as far as possible, to eat raw fruit and vegetables.
  • Feingold diet, also known as the Feingold program. Requires you to avoid a range of additives (such as synthetic colourings and flavourings, and preservatives) as well as salicylates (a natural plant chemical found in some foodstuffs and medicines)
  • Gut and Psychology Syndrome (GAPS) diet. A version of the selective carbohydrate diet which mainly excludes sugars and starches and which mainly consists of meats, fish, eggs, fermented foods and vegetables.
  • Gluten-free diet. Also known as the cereal-free diet. Requires you to avoid all sources of gluten, a protein found in some cereals such as wheat, oats, rye and barley.
  • Ketogenic diet, also known as the low carbohydrate diet and the starvation diet.  A high fat, adequate protein, low carbohydrate diet designed to mimic many of the biochemical changes associated with prolonged starvation.
  • Lutein-free diet. Requires you to avoid all sources of lutein, a carotenoid found in green leafy vegetables such as spinach and kale,
  • Nourishing Traditions diet, also known as the Weston A. Price diet. Requires you to consume a combination of traditional food types including saturated fats, unprocessed dairy products, sprouting grains, stocks and broths while avoiding processed foods.
  • Oxalate free or low oxalate diet. Requires you to avoid or reduce oxalates, crystals found in many plants where they concentrate light and boost photosynthesis.
  • Palaeolithic diet, also known as the paleo diet, caveman diet, stone age diet or hunter-gatherer diet. Requires you to follow the diet believed to have been followed by early humans i.e. eating mainly meat, fish, vegetables, fruit, roots and nuts, and avoiding grains, legumes, dairy products, salt and processed fat and sugar.
  • Phenol-free diet. Phenol, also known as carbolic acid, is an aromatic compound. Foodstuffs with high levels of phenol include apple juice, citrus fruit juice and chocolate. Specific programmes which restrict phenol include the failsafe diet, the Feingold diet, Sara's diet.
  • Purine free diet. Purines are nucleic acids found in the body and in some foods. Foodstuffs which have high levels of purines include some fish (such as anchovies and mackerel) some meats and meat products (such as beef, offal, and gravy) and some beverages, such as tea and coffee.
  • Salicylate free/low salicylate diet. Salicylates are natural plant chemicals common in many fruits, berries, and some vegetables, as well as honey, yeast extracts and almonds. Specific programmes which incorporate a salicylate-free diet include the Feingold diet.
  • Selective carbohydrate diet. Requires you to exclude or reduce some forms of complex carbohydrates, for example, all starches and complex sugars and replace them with simple carbohydrates e.g. glucose and fructose. The individual also uses appropriate dairy products (such as goat milk yogurt) or probiotics to repopulate the gut with beneficial bacteria.
  • Serotoninergic diet. Diet high in foods thought to boost the neurotransmitter serotonin - foods containing protein (and particularly the amino acid tryptophan) and food rich in carbohydrates.
  • Yeast-free diet, also known as the antifungal diet. Requires you to avoid fermented substances which contain yeasts (such as breads, vinegar, alcohol, cheese, soy sauce, coffee and processed meats) or substances which encourage yeasts to grow (such as natural and refined sugars, including fruit). Specific programmes which incorporate a yeast-free diet include the body ecology diet.

Cost and Time

Cost

The cost of following a special diet depends on things like the type of diet, whether the whole family is following the diet, whether you are buying ready-made meals or making them yourself.

For example, the major cost of following the gluten-free casein-free diet is buying gluten -free and/or casein -free foodstuffs, which are often more expensive than foodstuffs which contain these things. According to Stevens and Rashid (2008), gluten-free products were on average 242% more expensive than regular gluten containing products

In the UK, it is sometimes possible to obtain prescriptions for foodstuffs for patients in specific circumstances, such as when they have a confirmed diagnosis of coeliac disease but not if they have autism.

Time

Most special diets are designed to be followed seven days a week for months or years. The amount of time you need each week will depend on the type of diet and whether you are making all of the meals yourself. In addition, it takes time to check the labels of foods you buy to ensure that they do not contain restricted foodstuffs.

For example, some proponents of the gluten-free casein-free diet recommend a trial period of three or four months. If it has not worked within that time they say it is unlikely to do so. However some researchers also suggest that the most reliable trial results are obtained after you have been on the diet for more than a year.

However, most dietitians recommend that a 2-6 week trial of an exclusion diet followed by reintroduction is adequate to identify if a dietary change has been beneficial. This is backed up by the 2011 NICE guideline food allergy in under 19s: assessment and diagnosis that recommends “if non-IgE-mediated food allergy is suspected, trial elimination of the suspected allergen (normally for between 2–6 weeks) and reintroduce after the trial. Seek advice from a dietitian with appropriate competencies, about nutritional adequacies, timings of elimination and reintroduction, and follow-up.”

Risks and Safety

Hazards

There are many potential risks in withdrawing normal or regular foods from individuals, but especially young children.

Some autistic people are faddy eaters. They already have a less healthy and less varied diet than other people. Restricting what they eat even further may reinforce those rigid eating patterns. It may also increase their social isolation (because they can’t eat the same food as their friends at parties or restaurants).

In the long-term special diets could lead to health problems if they are not carefully balanced. For example, according to Marí-Bauset et al (2015),

“The combination of food selectivity and restrictive diets can make it difficult to achieve an adequate diet, consequently resulting in an excessive intake of certain foods and/or deficiencies and malnutrition due to insufficient amounts of other foods. In turn, inadequate intakes may lead to the development of chronic and degenerative conditions that tend to appear in the third or fourth decade of life (cardiovascular disease, high blood pressure, diabetes, dyslipidemia and osteoporosis, among others) or even earlier, in the case of menstrual disturbances, sleep apnea, and psychosocial disorders.”

Notes: diabetes, condition characterised by high blood sugar levels; dyslipidemia, an abnormal level of fatty acids; osteoporosis, brittle or fragile bones; sleep apnea, temporary suspension of breathing.

Specific diets:

There are some potential hazards associated with specific diets. For example,

  • According to the Healthy Food Guide website, accessed on 26 September 2016, “The poor range of foods [in the Gut and Psychology Syndrome diet] leaves a nutritionally inadequate diet. The introductory stage provides well below the recommended nutrient intake for vitamins, minerals and protein (as well as calories), putting people at risk of malnutrition.” It also notes that the “...  advice on diet in pregnancy and infancy contradicts government food safety guidance – for example, liver intake in pregnancy is not recommended in the UK, and raw eggs are not recommended for infants and young children.”
  • According to Connor (2014), the gluten-free, casein-free diet poses a number of potential risks including a low intake of calcium, iodine and fibre which can lead to weaker bones, iodine deficiency and gut problems. There is also a risk of masking undiagnosed coeliac disease if a coeliac disease test is not carried out before trialling the diet.
  • According to Kossoff et al. (2009), the ketogenic diet may produce a number of adverse side effects including gastrointestinal symptoms, carnitine deficiency and elevated lipids. More seriously “Children receiving the ketogenic diet continuously for more than six years are at high risk for kidney stones, bone fractures, and growth disturbances.”
  • According to Zelman (2011), the specific-carbohydrate diet “...can be a very challenging diet to follow because there are a limited number of foods allowed... Not only is the SCD difficult to follow, it may also be risky for your health. When you eliminate whole food groups like dairy and grains, you significantly reduce the nutritional quality of the diet, which may result in nutritional deficiencies.”

Contraindications

There are no known contraindications (something which makes a particular treatment or procedure potentially inadvisable) for most diets.  However, some diets can be very challenging and difficult to adopt, especially for some autistic people. For example, according to Evangeliou (2003),

“The classic ketogenic diet is very restrictive and requires a large amount of dietetic involvement in terms of calculations, monitoring, patient support, and motivation from the family to adhere to the diet; consequently, it is difficult to adapt for children with [learning disabilities].”

Autistic people or their carers who have concerns about their or their child’s diet should seek advice from a responsible health professional such as their health visitor or GP. This may lead to a referral to a dietitian, in particular one with experience of working with autistic people.

Suppliers and Availability

Suppliers

The supply and availability of the ingredients required for special diets varies enormously between different diets and sometimes between different countries. For example, obtaining gluten-free or casein-free ingredients can be difficult in some countries.

The quality of special diets varies enormously depending on the diet, the ingredients used, and how rigorously you follow the diet. Most specialist diets are unregulated and uncontrolled, since anyone can choose to follow them.

Various support groups exist which may be able to advise you on how to follow specific diets and there are usually resources (such as books or DVDs) which may also instruct you on how to follow those diets.

However, if you are contemplating following a special diet, you should seek advice from a paediatrician, GP or dietitian. The British Dietetic Association has information about qualified dietitians in the UK.

Credentials

There are no formal, internationally validated registered qualifications for people using most special diets for autistic people, since any individual, parent or carer can choose to implement the diets.

However, if you are contemplating such a significant change of diet you should definitely seek advice from a qualified medical practitioner, paediatrician and/or dietitian.

The British Dietetic Association has information about qualified dietitians in the UK.

Related Suppliers and Availability


History

The history of the use of special diets (dietetics) can be traced as far back as the writings of Homer, Plato and Hippocrates in ancient Greece. For example, Hippocrates is reported to have said “Let food be thy medicine and medicine be thy food.”

According to the British Dietetic Association website, accessed on 27 September 2016,

“The earliest dietary observations in hospitals go back to St Bartholomew’s Hospital in 1687. Evidence of the first therapeutic diet comes from the Radcliffe Infirmary, Oxford, in 1837 when observers noted 'the diet which suffering and exhausted nature sometimes requires after operations (mutton chops)'.  However dietetics really started from the middle of the nineteenth century when Florence Nightingale observed the importance of diet and nutrition to convalescence from the wars at that time.”

The history of particular diets varies from diet to diet.  For example, the specific carbohydrate diet was originally developed in the 1950's by Dr. Haas, a New York pediatrician, as a diet for coeliac disease. It was subsequently taken up and promoted by Elaine Gottschall, a New Jersey biochemist, to treat her daughter, who suffered from ulcerative colitis. The diet has since been taken up as a treatment for other conditions, including autism. 

The gluten-free, casein-free diet, on the other hand, was developed in the early 1980s. A number of researchers, including Herman and Panksepp, noted the similarities between the effects of opioids and the symptoms of autism. Panksepp suggested that autistic people might have high levels of opioids in their central nervous systems caused by undigested peptides. Thereafter some professionals and parents began to use the gluten-free casein-free diet in order to eliminate these peptides.

Current Research

Most special diets provide the same benefits for autistic people as they do to people who are not autistic. They do not appear to provide any additional benefits to autistic people, according to a limited amount of research evidence of sufficiently high quality.

No evidence at all supports the use of most special diets (such as additive-free diets, the specific-carbohydrate diet, and the yeast-free diet).

Determining the benefits of other diets (such as the gluten-free, casein-free diet or the ketogenic diet) for autistic people is not currently possible. We must wait until further research of sufficiently high quality has been completed.

Other Reading

This section provides details of other publications on this topic.

You can find more publications on this topic in our publications database.

If you know of any other publications we should list on this page please email info@informationautism.org

Please note that we are unable to supply publications unless we are listed as the publisher. However, if you are a UK resident you may be able to obtain them from your local public library, your college library or direct from the publisher.

Related Other Reading


Personal Accounts

This section provides personal accounts of special diets for autistic people.

Personal accounts can be useful sources of information about the intervention but are not as scientifically valid or reliable as research trials. This may be especially true where the accounts are published by an organisation which might gain a financial advantage from the take-up of the intervention.

Please note that the views expressed in these personal accounts do not necessarily represent our views.


There are numerous personal accounts of the benefits of different special diets as treatments for some of the problems facing autistic people.

Additional Information

Allergies

The 2011 NICE guideline recommends – “Do not use the following tests in the diagnosis of food allergy: vega test, applied kinesiology, hair analysis, IgG testing”, and that “If food allergy is suspected (by a healthcare professional or the parent, carer, child or young person), a healthcare professional with the appropriate competencies (either a GP or other healthcare professional) should take an allergy-focused clinical history tailored to the presenting symptoms and age of the child or young person.”

Related Additional Information


Updated
17 Jun 2022
Last Review
01 Jan 2017
Next Review
01 May 2023