Can a healthy diet help autistic children to thrive?
Could autism traits really be reversed through a targeted dietary and supplementation regime, combined with behavioural and speech therapy?
That’s the claim being made in a provocative paper published by Dr Heather Tallman Ruhm, a doctor and physician, and a group of scientists from the University of Maryland.
Dr Tallman Ruhm, who runs a non-profit initiative called the Documenting Hope Project which investigates new strategies for helping autistic children, is a proponent of the idea that what we eat can influence brain development. She believes that the remarkable rise in autism diagnoses – which rose by 787 per cent between 1998 and 2018 in the UK – is at least partially linked to modern diets rich in ultra-processed foods packed with industrialised chemicals.
“Much of what is considered food today is a far stretch from what it was 30, 40, 50 years ago,” she says.
In her study published in the Journal of Personalized Medicine, the researchers highlighted the case of twin girls who were diagnosed with level three autism spectrum disorder at 20 months, a diagnosis which indicates very substantial support needs. Both infants reportedly demonstrated significant verbal and non-verbal communication problems as well as repetitive behavioural characteristics.
With the support of the researchers, their parents switched them to a whole food diet, low in sugar, and which excluded gluten, dairy and all ultra-processed foods. In addition, they received behavioural and speech therapy and a range of supplements including omega-3 fatty acids, vitamin D, carnitine, a multivitamin and folate.
The extraordinary claim in the paper is that over the course of two years, this “reversed” autism. “The family changed to a very clean diet, so all organic, nutrient-dense foods,” says Dr Tallman Ruhm. “They did eat meat, but it was high in vegetables and fruits. In a fairly short time, they managed to make extreme progress.”
However, not everyone is convinced. The National Autistic Society reacted angrily, describing the suggestion that autistic traits and characteristics can be reversed as “deeply insulting”. Dr Rosa Hoekstra, a researcher in neurodevelopmental disorders at King’s College London, pointed out that the assessment of how the twin girls progressed over the two years was entirely based on anecdotal reports and descriptions from their parents, making it unreliable from a scientific perspective.
But at the same time, there are many scientists who feel that major dietary changes can go a long way to helping autistic children thrive, through improving their gut and brain health.
Here’s some of what we know, and the dietary changes some experts believe may help.
Don’t drink milk
Some studies have estimated that as many as 47 per cent of autistic children suffer from gastrointestinal issues such as constipation, diarrhoea and abdominal pain, although the exact figure varies significantly from one study to another.
“There are about 40 studies showing that kids with autism have abnormal gut bacteria, and we know that kids with autism have higher amounts of certain toxins in their guts,” says James Adams, a professor who leads the autism research program at Arizona State University. “They also have more allergies and there are many studies which show their immune system is on average, more reactive.”
A growing approach is a so-called casein-free diet which excludes all dairy products containing casein, the protein which gives milk its white colour. Casein is also found in yogurt, cheese and many infant formulas.
Prof Adams explains that casein is a common allergen which can be problematic for overactive immune systems. He says studies have also shown that autistic children have less lactase, the enzyme required to digest lactose, a sugar found in milk, meaning that they are less able to tolerate it.
“Some autistic kids also have what’s called cerebral folate deficiency,” he says. “Folate is a very important B vitamin and there are several studies showing [that in autistic individuals] it’s not transported well into the brain.
Some studies have found that 71 per cent of autistic people have so-called autoantibodies – proteins produced by the body which mistakenly attack its own cells and tissues – that actively block folate from getting in the cell. Prof Adams says that production of these autoantibodies seems to be exacerbated by consuming dairy products, and in autistic people who go on dairy-free diets, their levels are reduced.
Do eat good fats
According to Prof Adams, gastrointestinal problems can be exacerbated by the highly limited diets of some autistic children. “Many kids with autism just eat the same food day after day,” he says. “This causes imbalances leading to inflammation, especially if they’re eating too many processed foods. I’ve seen around 15 studies showing that autistic children have low levels of omega-3 fatty acids.
Some research has claimed that increasing levels of omega-3, either through diet or supplements, can aid autistic children with social communication when used alongside behavioural therapy, although this connection is still relatively unclear.
One nutrition regime which is sometimes used with autistic children is the GAPS (gut and psychology syndrome) diet, which is based around foods including fish, meat, shellfish, eggs, hard cheeses, nuts, white beans, fermented foods, fruit and non-starchy vegetables. Silvija Ābele, a nutritionist who researches the GAPS diet, says that the diet involves a number of foods which are rich in omega-3, such as oily fish.
“The brain needs omega-3 in order to function optimally,” says Ābele. “Everyone benefits from adding good fats into the diet but especially children and adults with autism spectrum disorder, ADHD, anxiety, panic attacks and depression.”
Don’t eat gluten
Dr Adrien Eshraghi of the University of Miami believes that one of the causes of behavioural problems in autistic children can be underlying pain, stemming from gastrointestinal problems. “It’s understandable that if you have very bad belly pain, and you cannot express yourself, this will manifest itself as inappropriate behaviour,” he says.
One commonly tried nutritional intervention which may help to reduce this discomfort, is to eliminate gluten. Dr Eshraghi explains that some studies have shown that autistic children do not metabolise gluten in the right way, ultimately impairing the production of a crucial chemical called glutathione which is involved in immune system function.
“Glutathione is a strong antioxidant,” Dr Eshraghi continues. “And we know that autistic kids have a high level of oxidative stress and inflammation in their body which contributes to these gastrointestinal issues. Eliminating gluten can help the body to produce more glutathione.”
Don’t eat porridge
As well as the GAPS diet, another dietary regime which has been studied in autistic children is the so-called specific carbohydrate diet. This is based on evidence that autistic children can find complex carbohydrates – such as oats and starchy vegetables like potatoes – difficult to digest due to the composition of their gut microbiome.
“Complex carbohydrates are very difficult to digest for an unhealthy gut,” says Ābele.
She explains that with many of the body’s key digestive enzymes not working properly, molecules which are the byproducts of undigested carbohydrates can end up floating around in the large intestine where they are fermented by pathogenic bacteria into toxins.
Because many autistic children also suffer from a leaky gut, where the small intestine is more permeable than it should be, these toxins then leach back into the blood where they can ultimately trigger symptoms such as bloating or pain.
Ābele says that removing these carbohydrates, either temporarily or permanently, can give the gut a chance to recover.
Do eat fermented foods
As well as excluding complex carbohydrates, the GAPS diet also encourages the consumption of fermented foods which can be a natural source of probiotics, potentially helping to shift the composition of the microbiome to a less inflammatory state.
“Fermented foods are possibly of some benefit,” says Prof Adams. “There have been about 10 studies of probiotics, and they seem to help a little bit.
Do take supplements
Some companies are already developing specific microbiome-targeting drugs with the aim of reducing irritability traits in autistic children, including aggression and tantrums, which researchers have suggested may be linked to the consequences of a leaky gut. A US company called Axial Therapeutics has developed an experimental product, which they describe as a tasteless and odourless powder that can be mixed with soft food and taken orally. It is designed to bind to toxins in the gut and help absorb them before they can leak back into the bloodstream. The company is currently testing it in ongoing clinical trials in autistic children in the United States, Australia and New Zealand.
Dr Tallman Ruhm’s paper also noted how different research groups have been investigating the possible benefits of various dietary supplements including vitamin D, vitamin B12, folate and carnitine for autistic people. Prof Adams says that the carnitine research is based around growing interest in the role of mitochondria, the cellular power plants which generate energy, in autism and related neurodevelopmental conditions.
In the past 12 years, scientists have accumulated various clues suggesting that mitochondria may function differently in some autistic people. A 2015 study from researchers at Drexel University College of Medicine detected low levels of mitochondrial activity in a third of autistic children, while a research collaboration from Swiss, Belgian, Dutch and American scientists in 2016 found that people with mitochondrial disease may have an elevated risk of autism or autism traits.
Carnitine is of interest, being one of the key nutrients for proper mitochondrial function, helping to transport fatty acids into mitochondria where they are used to generate energy. “We did a randomised, controlled study [in 2018] showing carnitine [along with a gluten-free, casein-free, and soy-free diet and other vitamin, mineral and fatty acid supplements] is helpful to autistic children,” says Prof Adams. “A second study then doubled the dose and gave supplements for twice as long and found even more benefit. With many autistic children, the mitochondria don’t work very well because of bad gut bacteria producing toxins which poison them. So they need extra support to function and produce energy for the body and brain.”
