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Introduction

Autism involves a range of complex characteristics. People with autism often experience difficulties with social communication, such as understanding what others say and expressing themselves clearly. They may also find social interaction challenging, including interpreting how others feel or expressing their own emotions. More research is now highlighting how nutrition and lifestyle factors can support overall wellbeing. While there is no single autism diet, a balanced and personalised approach to nutrition may help some individuals feel and function better.

Individuals with autism may have the following characteristics: 

Making repetitive movements, such as hand flapping or rocking, and having restrictive behaviours so that they dislike change but feel more secure when they are able to stick to routines they know.
Having ‘special interests’ that absorb their attention and are very important to them
Being over-sensitive or under-sensitive to light, sound, taste, touch or taste 
Being very anxious because they have difficulty understanding what is going on or what may happen next. 
Children may have meltdowns or shutdowns when they switch off because they feel overwhelmed. Sensory overload or anxiety that rises beyond what they can manage often triggers these reactions.

Background

The National Autistic Society estimates that around 700,000 people have autism in the UK with  three times more boys than girls effected¹.

Researchers have not identified a single cause, although evidence implicates genetic, neurodevelopmental and environmental factors¹. More people now view autism as a difference and a natural part of neurodiversity rather than a disorder.

There is growing evidence that nutrition and lifestyle interventions can be very supportive to individuals with autism. For example, many individuals with autism have severely disrupted digestion, so restoring balance in the gut is a key focus from a nutritional perspective. The following are also important nutritional and lifestyle factors for consideration:

balancing blood sugar
identifying food allergies, such as gluten and dairy
addressing nutrient deficiencies
ensuring an optimal intake of essential fats, most notably omega 3 fatty acids

Nutrition & Lifestyle Interventions

Improve digestion

Research has identified a possible link between the imbalances in the composition of microbiota in the gut of individuals with autism. This may relate to symptoms such as irritability and reduced concentration, which can develop when digestive issues like constipation or diarrhoea cause discomfort². Notably, many parents of autistic individuals report that their child has received repeated or prolonged courses of antibiotic drugs, for ear or other respiratory infections, during their first year, before the diagnosis of autism. Broad-spectrum antibiotics kill good as well as bad bacteria in the gut, and this may be why autistic individuals commonly have bowel irregularities.

If an individual has autism, restoring a healthy gut is vital. You can start simply, under the supervision of a doctor, by supplementing digestive enzymes, and giving probiotics to restore the balance of gut bacteria. Both measures may help to restore balance to the digestive tract and promote normal absorption. A recent study indicated that these measures produced positive clinical results in autistic individuals³. 

Key Actions for Improving Digestionove digestion

Increase Probiotics: key to digestion is having a balanced gut ecology. This means plenty of beneficial gut flora and lower levels of the non-beneficial strains. As previously discussed, antibiotics may imbalance flora. In addition, individuals who were not breastfed may also have fewer strains of beneficial bacteria, in comparison with breastfed individuals.  Increasing consumption of fermented foods, such as sauerkraut, kefir, kombucha, and kimchi is one means of increasing probiotics through food. It can also be beneficial to supplement probiotics to increase the presence of beneficial gut bacteria⁴. The most important strains are Lactobacillus Acidophillus and Bifidobacter.Saccharomyces boulardii, although technically a yeast rather than a bacterium, plays an important role in gut health. It is especially useful when a saliva test shows low levels of Secretory IgA (SIgA).

Supplement with digestive enzymes: Digestive enzymes provide assistance by helping to break down food, making the nutrients more available for absorption and relieving the strain on the digestive system, whilst it recovers. The amino acid glutamine is an important nutrient for gut healing, but it may be contraindicated in autism because some individuals have protein deamination problems that can lead to the production and build up of ammonia.⁶

Side effects: None reported

Contraindications with medication: Further courses of antibiotics will eliminate beneficial gut bacteria, and continuing to administer probiotics is therefore recommended. 

Balance Blood Sugar

There is much overlap between ADHD/hyperactivity and autism, so for autistic individuals who show signs of hyperactivity, improving blood sugar balance is an important consideration. 

Dietary studies consistently reveal that hyperactive individuals eat more sugar than other individuals⁷. A study of 265 hyperactive individuals found that more than three-quarters of them displayed abnormal glucose tolerance, – that is, their bodies were less able to handle sugar intake and maintain balanced blood sugar levels⁸.

When a individual is regularly snacking on refined carbohydrates, sweets, chocolate, fizzy drinks, juices and little or no fibre, protein and monounsaturated and polyunsaturated fats, to slow the glucose (sugar)absorption, the levels of glucose in their blood will seesaw continually. This may cause fluctuations in their levels of activity, concentration, focus and behaviour, and impact on brain function and development⁹.

Key Actions for Improving Blood Sugar Balance

To support blood sugar balance, it is really important to reduce consumption of sugary and processed foods and drinks, and limit caffeine consumption. Consume more whole foods, such as vegetables, fruit, wholegrains, fish, lean meats, such as turkey and chicken, nuts, seeds and pulses will help to support blood sugar levels.

Side effects: None reported

Contraindications with medication: Diabetes medication should be closely monitored by a doctor.

Increase Omega 3 Fats

Deficiencies in essential fats are common in people with autism. Research by Dr Gordon Bell at Stirling University has shown that some autistic individuals have an enzymatic defect that removes essential fats from brain cell membranes more quickly than it should¹⁰. This means that autistic individuals are likely to need a higher intake of essential fats.Researchers have found that supplementing EPA, which can slow the activity of the defective enzyme, has clinically improved behaviour, mood, imagination, spontaneous speech, sleep patterns and focus in autistic individuals. Clinical trials have since tested omega 3 supplementation and found that when individuals with autism received omega 3 supplements, they showed improvements in symptoms such as hyperactivity, social ability, concentration, irritability and aggression^11,12.

Key Actions for Increasing Omega 3 Fats

Eat oily fish, such as salmon, mackerel and sardines, at least twice a week, and seeds, such as flaxseeds (also called linseeds) and chia seeds, on most days. Furthermore, supplement omega 3 through fish oil or a vegan alternative. Look for a supplement that contains both EPA and DHA.

The best fish for EPA, the type of omega 3 fat that’s been most thoroughly researched are: mackerel (1,400mg per 100g/3oz), herring/kipper (1,000mg), sardines (1,000mg), fresh (not tinned) tuna (900mg), anchovy (900mg), salmon(800mg), trout (500mg). Tuna, being high in mercury, is best avoided in autism due to heavy metal considerations.

The best seeds are flax seeds and chia seeds. Because flax seeds are so small, it’s best to grind them and sprinkle them over cereal. Alternatively, use flaxseed oil, for example in salad dressings. While these seeds technically provide omega 3, only about 5 percent of their alpha linolenic acid is converted by the body into EPA. Therefore individuals who are following a plant based diet may benefit from supplementing with vegan omega 3 supplements.

Side effects: Causes loose stools in sensitive individuals if they are started on too high a dose.

Contraindications with medication: Essential fats may have a ‘blood-thinning’ effect and should not be mixed with ‘blood thinning’ medication, such as warfarin or heparin. Always consult your doctor before commencing a new supplement.

Increase vitamins and minerals

Vitamin B6, Vitamin C and Magnesium

We have known since the 1970s that a nutritional approach can help autism, thanks to the pioneering research by Dr Bernard Rimland of the Institute for individual Behaviour Research in San Diego, California. He showed that vitamin B6, C and magnesium supplements significantly improved symptoms in autistic individuals. In one of his early studies in 1978, researchers observed that 12 of the 16 autistic individuals improved, then regressed when the vitamins were replaced with placebos¹⁴. Other studies, however, have failed to confirm conclusively  positive outcomes with certain nutrients. For example, a French study involving 60 autistic individuals found significant improvements when they took a combination of vitamin B6 and magnesium, but not when either nutrient was given on its own.¹⁶. 

Key Actions for Increasing B6, Vitamin C and Magnesium

Dark, leafy green vegetables, chickpeas and salmon are great sources of B6. Peppers, citrus fruits, broccoli and cauliflower are good sources of Vitamin C. Green vegetables, nuts, seeds, cacao and wholegrains are all foods which are sources of magnesium. It is always best for foremost obtain these nutrients, and indeed all nutrients, from food. Some individuals may benefit from supplementation, and one way to do this is by using a multivitamin and mineral complex. However, it is essential to speak with your doctor and a registered dietitian or nutrition practitioner to make sure this approach is appropriate and safely tailored to your needs.

Side effects: Many of these foods discussed above include fibre, which may increase bowel movements. It is important to ensure you are consuming the recommended 2L of water per day, to prevent bloating as a result of the increased fibre intake.

Contraindications: If considering supplementation, discuss with your doctor, and a dietitian / nutrition practitioner who is registered, beforehand.

Vitamin A

Paediatrician Dr Mary Megson from Richmond, Virginia, indicated that many autistic individuals are lacking in vitamin A.Vitamin A is essential for vision, and vital for building healthy cells in the gut and brain¹⁷. Megson began speculating what might happen if these individuals were not getting enough natural vitamin A. She realised that not only would this affect the integrity of the digestive tract, potentially leading to allergies, but it may also affect brain development and vision. Both brain differences and visual defects have been detected in autistic individuals. The visual defects, Megson deduced, were an important clue because lack of vitamin A may cause poor black and white vision, a symptom often seen in the relatives of autistic individuals. If you cannot see black and white, they cannot see shadows, and without that you lose the ability to perceive three-dimensionality.

This in turn leaves you less able to make sense of people’s expressions, which could explain why some autistic individuals tend not to look straight at you, but rather sideways sideways. Long thought to be a sign of poor socialisation, this sideways technique may in fact be the best way for them to see people’s expressions, because there are more black and white light receptors at the edge of the visual field than in the middle of the eye ¹⁷. 

Key Actions for Increasing Vitamin A

The best sources of vitamin A (retinol) are breast milk, organ meats, milk fat, fish and cod liver oil, none of which are generally prevalent in 21st century Western diets. Retinol can also be synthesised from beta-carotene, which is present in plant foods, such as carrots and sweet potatoes (yams), but this conversion process is impacted by factors such as existing Vitamin A status, as well as levels of iron, zinc, and protein.

Side Effects: An important point regarding formula milk, fortified food and multivitamins, is that many of which contain altered forms of Vitamin A, such as retinyl palmitate, which is not utilised as efficiently as Vitamin A derived from animal-products, such as meat and fish. 

Contraindications: Foods that are high in vitamin A in its retinol form, such as liver, and vitamin A supplements that contain retinol are contraindicated in pregnancy because they can negatively affect the developing foetus. Vitamin A supplements also require caution for people with liver disease, kidney disease, alcoholism or acne vulgaris. It should also be noted that beta carotene supplements are contraindicated for individuals who are either smoking presently or have a history of smoking, and / or have a experienced asbestos exposure due to concerns regarding increased lung cancer risk.

Vitamin D

Recent research and clinical trials have highlighted a possible link with autism and vitamin D levels. In a study on individuals with autism, when vitamin D status was compared to their counterparts it was found that individuals with autism had significantly lower vitamin D levels. When individuals were supplemented with vitamin D3 (300IU/kg/day) for 3 months, 80% of participants were observed to have significantly improved symptoms such as attention span, eye contact, behaviour ¹³ .

Key Actions for Increasing Vitamin D

Some foods, such as milk and mushrooms, contain vitamin D. However, the body gets most of its vitamin D from sunlight, and this can vary depending on the time of year.For this reason, the UK government currently recommends that many populations supplement 10mcg (400IU) of Vitamin D daily. Individuals who have a darker skin tone, have a higher BMI, and are from particular religious groups which encourage skin to be largely covered up are at a higher risk of Vitamin D deficiency.

Side Effects:

Abdominal pain, headache, nausea, skin reactions (common).
Appetite decrease, arrhythmia, constipation, diarrhoea, hypertension, myalgia, thirst, vomiting, weight decrease (uncommon).

Contraindications: Vitamin D medications can contraindicate with anti-epilieptic medications, Orlistat (weight loss medication), heart medications, steroids and diuretics, so always consult a doctor before consuming Vitamin D supplements. Pregnant and breastfeeding individuals should also seek advice from their midwife and doctor before supplementation.

Avoid food allergies

Why food sensitivities matter

One of the most significant contributing factors in autism appears to be undesirable foods and chemicals that often reach the brain via the bloodstream because of faulty digestion and absorption. Much of the impetus for recognising the importance of dietary intervention has come from parents who have noticed vast improvements in their individuals after changing their diets.

Gluten, casein and exorphins

The strongest direct evidence of foods linked to autism involves wheat and dairy, and the specific proteins they contain – namely, gluten and casein. These are difficult to digest and, especially if introduced too early in life, may result in an allergy. Fragments of these proteins, called peptides, can have a major impact on the brain. They can act directly on the brain by mimicking the body’s natural opioids, such as enkephalins and endorphins, which is why they are sometimes called exorphins. Or they can disable the enzymes that would break down these naturally occurring compounds. In either case, the consequence is an increase in opioid activity, leading to many symptoms we describe as autism. Researchers at the Autism Research Unit at Sunderland University have found increased levels of these peptides in the blood and urine of individuals with autism¹⁸.

Exorphin peptides form when the body only partially digests certain proteins, especially those found in foods that contain gluten and casein. One of these, called IAG, is derived from gluten in wheat,  and has been detected in 80 per cent of autistic patients. A key issue is the poor digestion of proteins. Low levels of zinc and vitamin B6 can contribute to this because both nutrients are essential for producing adequate stomach acid and supporting protein digestion, and they are often deficient in autistic individuals¹⁹. Dr Robert Cade, professor of medicine and physiology at the University of Florida, has observed that as levels of peptides in the blood decrease, some symptoms of autism may decrease. ‘If [levels of peptides] can be reduced to normal range,’ he says, ‘we typically see dramatic improvements.’

How to apply dietary changes safely

If you decide to go down this route with your individual, you’ll need to take a slow approach. The Autism Research Unit at Sunderland University recommends a gradual withdrawal of foods, waiting three weeks after the removal of dairy foods (casein) before removing wheat, barley and rye (gluten) from the diet. Initially, your individual may go through ‘withdrawal’ and their symptoms may get worse for a bit.

Keep a food diary and note your individual’s behaviours and symptoms alongside all the foods they’re eating. This can help to identify which of the usual suspects they are sensitive to – citrus fruits, chocolate, artificial food colourings, salicylates, eggs, tomatoes, avocados, aubergine, red peppers, soya and corn. But remember, most of the foods on this list also provide valuable nutrients, so you need to make sure they are replaced with suitable alternatives rather than simply removed.

Professional support

This entire process is best done under the guidance of a doctor and a qualified nutritionist or dietitian²¹.

Key Actions for Addressing Food Allergies

Consider contacting your doctor and requesting testing for food allergies. A wheat and dairy free diet may be helpful for some, but not all, individuals with autism. However, people should only make these changes under the supervision of a doctor, dietitian or nutritionist. Professional guidance ensures that people include suitable replacement foods and avoid nutritional deficiencies.

Side effects: Symptoms can worsen if changes are made too quickly. Any major dietary changes should be supervised by a qualified dietitian or nutrition practitioner who has experience in this area.

Contraindications with medication: None reported

Disclaimer: Always discuss with your doctor and a qualified, registered dietitian or nutrition practitioner before beginning any supplements

Researcher: Ellie Winch, MSc & ANutr (AfN)

Reviewed by: Dr Rona Tutt, PhD & OBE

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