Altering gut bacteria to treat autism

After a review of more than 150 papers on autism and gut bacteria, scientists from the US and China have suggested that alteration of the gut microbiome may reduce symptoms of the disorder. 

Since the 1960s, scientists have been reporting links between the composition of bacteria in the gut and autistic behaviour. Now, the team behind the review – which also highlights many studies showing that restoring a healthy balance in gut bacteria can treat Autism Spectrum Disorder (ASD) symptoms – have called for large-scale studies into the effects of altering the makeup of bacteria in the gut.

Dr Qinrul Li, from Peking University, China and first author of the study published in Frontiers, said: “To date there are no effective therapies to treat this range of brain developmental disorders. The number of people being diagnosed with ASD is on the rise. As well as being an expensive condition to manage, ASD has a huge emotional and social cost on families of sufferers.”

The team of researchers suggest instead of rehabilitation, educational interventions and drugs to reduce Autism Spectrum Disorder (ASD) symptoms, it could be as simple as a change in diet.

Gut health

The link between the gut and ASD is well known, with sufferers commonly reporting constipation and diarrhoea. The cause of many gastrointestinal problems is an imbalance of ‘good’ and ‘bad’ bacteria. The researchers suggest that an increase in bad bacteria in the stomach can lead to an overproduction of toxins, which affects the permeability of the gut lining. These toxins, undigested food and by-products can then make their way into the bloodstream and affect a child’s developing brain.

Dr Li, said: “ASD is likely to be a result of both genetic and environmental factors. The environmental factors include the overuse of antibiotics in babies, maternal obesity and diabetes during pregnancy, how a baby is delivered and how long it is breastfed. All of these can affect the balance of bacteria in an infant’s gut, so are risk factors for ASD.”

The researchers’ review found that taking probiotics, prebiotics, a change in diet – gluten or casein–free – and faecal transplants all had a positive impact on symptoms. These included increased sociability, a reduction in repetitive behaviour and an improvement in social communication.

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