Researchers are exploring the role of the microbiome in autism. Probiotics help introduce more good bacteria into your system and may help reduce GI symptoms associated with autism.

Our bodies are home to trillions of microbes — collectively called our microbiome. The microbiome is made of thousands of different species of bacteria, and its specific makeup plays an important role in your health.

When there’s too much of a certain kind of bacteria, or too little of another, it can lead to gastrointestinal (GI) issues and other health problems. It may even affect the central nervous system (the brain and spinal cord).

A growing body of research has been exploring the gut-brain connection and its role in autism. Researchers are looking at the early development of the microbiota during the gestational period and early infancy. They’re also looking at other factors, like the use of antibiotics, that could affect the microbiome’s composition.

Probiotics are one proposed therapy to help improve the balance of bacteria in the microbiome. Another is microbiota transfer therapy (MTT), a type of fecal transplant.

Research into the role of the microbiome in neurological disorders like autism is still in its early stages. Most of the existing studies have been done in either animal studies or small clinical trials. But, results have been encouraging and suggest the need for further research.

Within the last decade, our understanding of the gut-brain axis has increased significantly. But much is yet to be learned. Long-term, randomized clinical trials are necessary before researchers can narrow in on whether treating the microbiome will have therapeutic or protective effects.

This is made difficult by the fact that the composition of the microbiome is influenced by so many factors, which can change throughout the lifespan.

Some of the factors that influence early-life microbiome composition include:

  • genetics
  • maternal or infant antibiotics
  • maternal diet and exercise
  • maternal weight
  • breast or formula feeding and formula composition
  • method of delivery (vaginal or cesarian)

How is gut health linked to the brain?

According to a 2022 study, there’s a bidirectional link between the gut and the brain. Recent findings demonstrate that gut microbiota may influence numerous neurological disorders, including autism.

Early research indicates that an imbalance of gut microbiota may be a risk factor for:

  • Parkinson’s disease
  • Alzheimer’s disease
  • autism
  • multiple sclerosis (MS)
  • stroke

Gastrointestinal (GI) problems are one of the most prevalent symptoms in autistic people. Estimates suggest that about 70–80% of autistic people experience GI conditions, such as:

  • abdominal pain
  • constipation
  • diarrhea
  • vomiting

In a 2020 study, 255 young autistic children (ages 2 to 3.5) were compared to 129 neurotypically developing children of the same age. Overall the autistic children were 2.7 times more likely to have GI symptoms compared to their typically developing peers.

One small observational study based on parent reports indicates a possible association between the number or severity of GI problems in autistic children and certain behavioral symptoms. This could include:

  • self-injury
  • aggressive behavior
  • stereotyped behavior
  • sleep problems

Probiotics are live beneficial bacteria that are consumed as food or supplements. Probiotics may help increase the number of good bacteria in your gut and help improve the balance of your microbiome.

Giving probiotics to autistic children may help improve GI problems.

Research suggests that rebalancing the composition of the gut microbiota might help improve symptoms like anxiety and social or behavioral issues. But various methods of intervention require more research. Therapies to improve the balance of the microbiome include:

  • probiotics
  • dietary interventions
  • prebiotics
  • antibiotics
  • microbiota transfer therapy

According to a review of research, probiotics containing Lactobacillus, particularly, Lactobacillus plantarum, may reduce symptoms like anxiety and social or behavioral problems in children with autism.

A note on neurodivergent people

It’s important to note that there’s no “cure” for autism, as it’s a neurodevelopmental disorder rather than a disease.

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Probiotics have a long history of relatively safe use, particularly in healthy people. But detailed research is lacking on the safety of probiotics, so there’s not much information on the frequency or severity of side effects.

According to the National Center for Complementary and Integrative Health (NIH), potential risks of probiotics in the general population might include:

  • infection
  • production of harmful substances by the probiotic microorganisms
  • developing a resistance to antibiotics

People with severe illnesses or compromised immune systems may be at greater risk for probiotic side effects.

Discuss probiotic use with your doctor before starting supplementation.

  • Researchers are exploring the connections between autism, GI disorders, and the gut microbiome.
  • Probiotics are a good source of healthy bacteria and may help balance your microbiome.
  • More research is needed before any recommendations can be made about the effect of probiotics on autism.