Examining the links between food and autism spectrum disorder

The right diet can help manage the symptoms of autism and ADHD. Stephanie Karl explains the science behind it.

Children with autism tend to experience frequent infections, food allergies and sensitivities. Kurskov Yevgeny/ITAR-TASS Photo/Corbis

If food is the most natural way to nourish the body, it can be agreed that nutrition influences the health, learning and behaviour of children. Common physical and biochemical conditions often respond better if treated as a whole-body disorder rather than in isolation, and addressing underlying health issues through diet and nutrition has led to improvements in symptoms. The Autism Research Institute and similar organisations strongly believe that diet can influence the functioning of the body and the brain to affect learning, behaviour and mental health, by correcting biochemical imbalances.

Because the body and brain are connected, you can reduce, or eliminate, symptoms of autism spectrum disorders and attention deficit hyperactivity disorder (ADHD) by paying special attention to the food and nutrition children receive. While there is no one-size-fits-all dietary approach, supplying the body with what it needs to encourage natural healing, avoiding the things that cause inflammation and high oxidative stress, and boosting the capacity for improved digestion, energy transport and detoxification are key areas of focus.

There is scepticism among some clinicians as to the effectiveness of diet and supplements to reduce the symptoms of autism, but in the absence of specific testing to identify the underlying cause, it is interesting to consider the scientific rationale.

The focus on healing without medication is based on comparing the underlying causes and common physical symptoms of children with autism spectrum disorders with neurotypical children. Science has identified the autism group as having many statistically significant differences in their nutritional and metabolic status. Deficiencies and metabolic abnormalities are significant and provide a framework for clinicians to apply practical knowledge and individualised insight to create appropriate food and nutrition plans for each child.

Children with autism spectrum disorders routinely display symptoms such as constipation, diarrhoea, bloating and other digestive issues, frequent infections, food allergies and sensitivities, disturbed sleep patterns, inflammation, poor focus and attention, repetitive behaviours and problems socialising.

They also tend to have lower levels of vitamin B5, vitamin E, total carotenoids, folate and vitamin B3. Other commonalities include low lithium (a mood stabiliser) levels, plus iodine (essential for thyroid) and calcium (vital for bone health, nerve function, muscle contraction and blood clotting) are often below normal ranges. The amino acid tryptophan (a key ingredient in the production of serotonin, which influences depression, anxiety and sleep) is generally substantially lower in the autism group, while the neurotransmitter glutamate is often high and can be a factor in hyperactivity.

Introducing supplements to address these deficiencies is not a cure-all and must be done carefully and only after considering each child’s symptoms and requirements on an individual basis. When using supplements, it’s important to avoid accumulation, which can increase anxiety and cause pervasive learning and developmental delays.

For many children, research shows that physiological and behavioural symptoms of autism and ADHD may stem from, or be aggravated by, impaired digestion and gastrointestinal health. Poor digestion can cause malabsorption of nutrients that are essential to biochemical and brain function. This can stem from environmental factors, genetics, lack of beneficial intestinal bacteria, or be due to inflammation and immune-system responses to foods. Gluten (protein found in wheat) and casein (protein found in milk) commonly create an opiate or inflammatory reaction if not digested properly. This opiate effect influences the brain much like other morphine-type molecules, which is what makes cheese so addictive and enjoyable. Levels of key nutrients zinc and iron are often low in those with autism and ADHD, and therefore should be routinely tested and corrected.

Not only are the gut and brain connected, but many other body systems and biochemical pathways also affect the functioning of the brain.

As mentioned above, opiates can be created by inadequate breakdown of gluten, casein and soy, increasing sensitivity to pain, triggering irritability and a foggy brain, which causes lack of focus and attention.

Inflammation in the gut and brain, caused by toxins, food sensitivities, resident bacteria and yeast overgrowth, can cause pain and influence behaviour such as head banging and leaning over chairs to relieve stomach pain.

A reduced ability to rid the body of toxins can also cause a drug-like effect on the neurotransmitters in the brain, resulting in irritability and aggression. Food chemicals such as MSG, salicylates, preservatives, mercury and aluminium are common culprits.

Yeast overgrowth is prevalent in children with autism spectrum disorders to the extent where the yeast toxins enter the body and influence the brain. As Hippocrates wrote: “All disease begins in the gut” – and digestion and gut health affect many of the body systems.

Following a diet that supports good digestion is essential and can improve the symptoms of autism. A plan of action is to remove the offending and inflammatory foods, while adding nutrient-dense foods that heal the gut.

Correcting nutrient deficiencies with good-quality digestible foods and supplements can improve liver function and its ability to detoxify. Avoid food chemicals and environmental exposure to chemicals and sprays, as these can increase hyperactivity, aggression, irritability and self-harm behaviour.

A measurement of the effectiveness of diet and supplementation may well rely on anecdotal accounts from parents and teachers. Of note are improvements in expressing and receiving language, play, cognition, hyperactivity, tantrums, eye contact, speech, gastrointestinal health, sleep, sociability and an overall change towards paralleling peer developmental stages.

Through proper nutrition and monitoring, autism spectrum disorders and ADHD can be managed.