Treating autism by targeting the gut

June 19, 2017, Frontiers
Credit: CC0 Public Domain

Experts have called for large-scale studies into altering the make-up of bacteria in the gut, after a review showed that this might reduce the symptoms of Autism Spectrum Disorder (ASD). Until now, caregivers have relied on rehabilitation, educational interventions and drugs to reduce ASD symptoms, but now researchers suggest that treating this condition could be as simple as changing their diet.

A review of more than 150 papers on ASD and gut bacteria found that since the 1960s, scientists have been reporting links between the composition of bacteria in the gut and autistic behaviour. The review highlights many studies showing that restoring a healthy balance in can treat ASD symptoms.

"To date there are no effective therapies to treat this range of brain developmental disorders", explains Dr Qinrui Li of Peking University, China. "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 link between the gut and ASD is well-known among sufferers: problems like diarrhoea, constipation and flatulence are commonly reported. The root of gastro-intestinal problems like these is an imbalance of "good" and "bad" bacteria in the gut.

A cheap and effective treatment?

Many of the papers reviewed support the idea of a gut-brain axis - a way in which factors in the gut can affect processes in the brain. So these gastro-intestinal problems may have a more sinister side. The overgrowth of bad bacteria in the gut inevitably leads to an overproduction of by-products - including toxins. These can make the gut lining more permeable. Then toxins, by-products and even undigested food can get into the bloodstream and travel to the brain.

In a child under three years old, whose brain is at the height of development, the presence of these chemicals can impair neuro-development, leading to ASD.

What causes infants to develop an imbalance in the gut microbiota?

"ASD is likely to be a result of both genetic and environmental factors" explains Dr Li. "The 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 in an infant's gut, so are risk factors for ASD".

However, the researchers found a significant body of evidence that reverting the to a healthy state can reduce ASD symptoms.

"Efforts to restore the gut microbiota to that of a healthy person has been shown to be really effective" continues Dr Li. "Our review looked at taking probiotics, prebiotics, changing the diet - for example, to gluten- and casein-free diets, and faecal matter transplants. All had a positive impact on symptoms ".

These include such things as increased sociability, a reduction in repetitive behaviour, and improved social communication: all hugely beneficial to the life of an ASD sufferer.

The message of this review is one of positivity. This could well be a breakthrough in the treatment of this disorder. However, the researchers believe that the studies are too few and too small, and that new clinical trials are needed to take this research to the next level.

"We are encouraged by our findings, but there is no doubt that further work needs to be carried out in this field" says Dr Li. "We need more well-designed and larger-scale studies to support our theory. For now, behavioural therapies remain the best way to treat ASD. We would hope that our review leads to research on the link between the gut microbiota and ASD, and eventually a cheap and ".

Explore further: Intestinal bacteria alter gut and brain function

More information: Qinrui Li et al, The Gut Microbiota and Autism Spectrum Disorders, Frontiers in Cellular Neuroscience (2017). DOI: 10.3389/fncel.2017.00120

Related Stories

Intestinal bacteria alter gut and brain function

March 1, 2017
Research from McMaster University has found that bacteria in the gut impacts both intestinal and behavioural symptoms in patients suffering from irritable bowel syndrome (IBS), a finding which could lead to new microbiota-directed ...

Food and antibiotics may change microorganisms in gut, causing IBS

January 27, 2017
A recent review of research suggests that changes to the microorganisms (microbiota) in the gastrointestinal (GI) tract may be a cause of irritable bowel syndrome (IBS). The review article is published in the American Journal ...

How our gut bacteria affect cancer risk and response to treatment

May 11, 2017
The trillions of bacteria living in our gut (called the gut microbiota) can help determine our risk of cancer, as well as how we might respond to cancer treatment.

New research links Gulf War Illness to gastrointestinal disturbances

March 23, 2017
A new study from the University of South Carolina has found a gastrointestinal link that could help explain many of the health issues facing those with Gulf War Illness (GWI) as well as opening new pathways to treatment options ...

Gut bacteria may play a role in Alzheimer's disease

February 10, 2017
New research from Lund University in Sweden has shown that intestinal bacteria can accelerate the development of Alzheimer's disease. According to the researchers behind the study, the results open up the door to new opportunities ...

New research suggests more sensitive approaches to detect and monitor inflammatory bowel disease

May 15, 2017
A University of Manchester test on the mucus lining of the intestine, performed in mice, has found changes in bacteria that could lead to inflammatory bowel disease 12 weeks earlier than previously possible through looking ...

Recommended for you

Scientists just beginning to understand autistic adults' unique health needs

May 11, 2018
In the 1990s, the prevalence of autism spectrum disorder (ASD) among children rose sharply. These children are now entering adulthood, yet physicians and scientists know very little about the health outcomes they might face. ...

Meet Nao, the robot that helps treat kids with autism

May 9, 2018
(HealthDay)—It may seem counterintuitive, but a robot might help kids with autism interact better with humans.

New study links strong pupillary light reflex in infancy to later autism diagnosis

May 7, 2018
A new study published in Nature Communications shows that infants who are later diagnosed with autism react more strongly to sudden changes in light. This finding provides support for the view that sensory processing plays ...

Scientists find possible autism biomarker in cerebrospinal fluid

May 2, 2018
Autism diagnosis is slow and cumbersome, but new findings linking a hormone called vasopressin to social behavior in monkeys and autism in people may change that. Low vasopressin in cerebrospinal fluid was related to less ...

New research shows that children with autism are able to create imaginary friends

May 2, 2018
Playing with an imaginary companion (IC) helps children learn essential social skills such as empathy with other people. It is often believed that autistic youngsters are incapable of creating pretend play pals—a further ...

EEG signals accurately predict autism as early as three months of age

May 1, 2018
Autism is challenging to diagnose, especially early in life. A new study in the journal Scientific Reports shows that inexpensive EEGs, which measure brain electrical activity, accurately predict or rule out autism spectrum ...

2 comments

Adjust slider to filter visible comments by rank

Display comments: newest first

dirk_bruere
not rated yet Jun 19, 2017
This was previous viewed as pseudo-science
Gigel
not rated yet Jun 19, 2017
One can imagine what food preservatives could do to a healthy organism vie the gut-brain link. One day those substances will be banned.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.