A preference for foods such as wholemeal pasta or cheese spread may be linked to autism through subtle effects on the immune system, a new study has suggested.
Researchers from Shandong University Qilu Hospital in China analysed genetic data that can give clues about people’s long-term eating habits.
This allowed them to explore whether lifelong dietary patterns are associated with autism.
Among nearly 200 foods examined, two stood out. Wholemeal pasta, which contains gluten, and cheese spread, which is rich in casein, a milk protein, were both linked to a higher likelihood of autism in the analysis.
Bananas showed the opposite pattern, with people more inclined to eat them appearing less likely to be autistic.
Summarising their findings, the researchers wrote: ‘Our study suggests that the intake of wholemeal pasta and cheese spread is a risk factor for autism spectrum disorder.’
Autism is often accompanied by digestive problems such as constipation, diarrhoea and abdominal pain, and some studies suggest differences in gut bacteria in autistic people.
Because of this, diet has become an area of growing interest – although experts say evidence that dietary changes improve autism symptoms remains mixed.
A controversial study has found that cutting out gluten and dairy could help manage autism traits
As a result, some families try altering what their children eat, including cutting out gluten and dairy.
These approaches are widely debated, and medical opinion is divided over whether they help autistic children in general or only a small subgroup with digestive problems.
In the new study, published in the journal Frontiers in Nutrition, researchers carried out two separate analyses.
First, they examined large genetic datasets to see whether people with a lifelong tendency to eat certain foods were more or less likely to be autistic.
The researchers stress this does not mean eating or avoiding specific foods causes autism, or that diet can prevent it. Autism is present from birth, even if it is not diagnosed until later in childhood.
The team also explored whether immune activity might help explain the links they observed.
They found signs that cheese spread, in particular, was associated with changes in immune markers linked to infection and inflammation, though the effects were small and complex.
In the second part of the study, researchers reviewed medical records from 78 autistic children aged between two and seven.
Experts believe that one of the causes of behavioural symptoms in autistic children can be underlying pain, stemming from gastrointestinal issues
With their parents’ support, around half followed a gluten- and dairy-free diet for between six months and a year, while the rest continued with their usual diet.
The researchers tracked changes in behaviour, including repetitive actions, speech patterns and social interaction. They also measured immune markers linked to sensitivity to milk and wheat.
By the end of the study period, there was no clear difference in standard autism symptom scores between the two groups. However, children who avoided gluten and dairy showed a marked drop in immune antibodies linked to milk and wheat.
The authors said this showed that diet could influence immune responses, writing that ‘adhering to a gluten-free, casein-free diet can effectively modulate food-specific immune responses.’
However, they cautioned that this does not mean diet is a treatment for autism. In the paper, they stressed: ‘Dietary modifications may help support the overall health of individuals with ASD but are not a direct treatment for ASD.’
Independent experts say studies like this can help spot patterns but cannot prove that foods cause autism or that changing diet is an effective therapy. They also warn that restrictive diets can carry risks if not carefully managed, particularly for young children.
The researchers themselves acknowledged the limits of their work, noting: ‘Due to the relatively small sample size of the current study, further validation in large, multicentre studies is needed.’
According to the National Autistic Society, more than one in 100 people in the UK are on the autism spectrum, including around 700,000 adults and children.
Autism is a lifelong developmental condition that affects how people communicate, interact and experience the world. It is not an illness, and autistic people are born autistic, even if signs are not recognised until later in life.
