A common food in 70 percent of American diets may be fueling mental illness, dementia and autism.

A major new review has linked ultra-processed foods (UPFs) – which includes everything from chips to protein bars – to rising rates of neurological disorders.

Researchers believe the hidden culprit could be microplastics, tiny plastic particles now found in soaring levels inside UPFs — and increasingly, in the human brain.  

Studies have shown UPFs are more susceptible to microplastics as contamination can occur during processing and packaging of the foods – which are often in plastic wrappers and containers. 

Co-lead author of the new paper Dr Nicholas Fabiano, from the University of Ottawa, said: ‘We’re seeing converging evidence that should concern us all. 

‘Ultra-processed foods… contain significantly higher concentrations of microplastics than whole foods. 

‘Recent findings show these particles can cross the blood-brain barrier and accumulate in alarming quantities.’

Another author of the article, Dr Wolfgang Marx from Deakin University’s Food & Mood Center, said there is ‘remarkable overlap’ in the way UPFs and microplastics harm mental health. 

Ultra-processed foods (UPFs) – which includes everything from chips to protein bars – has been linked to rising rates of neurological disorders (stock image)

Dr Nicholas Fabiano, from the University of Ottawa, said: ‘We’re seeing converging evidence that should concern us all

He explained: ‘This hypothesis is particularly compelling because we see remarkable overlap in biological mechanisms.

‘Ultra-processed foods have been linked to adverse mental health through inflammation, oxidative stress, epigenetics, mitochondrial dysfunction, and disruptions to neurotransmitter systems. 

‘Microplastics appear to operate through remarkably similar pathways.’

In the new article, published in Brain Medicine, the authors reviewed studies that looked at the relationship between ultra-processed foods, microplastics and mental health. 

One of the studies included in the article was a recent one published in The British Medical Journal. It found people who consumed UPFs had a 22 percent higher risk of depression, a 48 percent higher risk of anxiety and a 41 percent higher risk of poor sleep – which can cause a cascade of poor health outcomes itself. 

And another study included found microplastics and nanoplastics induce oxidative stress on the central nervous system, which may cause cellular damage and increase the vulnerability to neurological disorders.  

Based on the authors’ review of the current data, they concluded the high levels of microplastic contamination in ultra-processed foods could be why they have such detrimental impacts on health. 

Scientists think ultra-processed foods damage your gut, and that can in turn damage with your brain. 

This connection — called the gut-brain axis — means when your gut’s out of whack, your mood and mental health can take a hit too.

Research has also shown that these junk foods are full of artificial sweeteners, which may throw off the way your brain cells talk to each other and disrupt hormones. 

On top of that, microplastics in the foods could be linked to depression and anxiety, with researchers warning they might harm brain development, trigger inflammation, and disrupt sleep and mood. 

Ultra-processed foods contain high concentrations of microplastics. Contamination can occur during processing and packaging of the foods – which are often in plastic wrappers and containers.

Microplastics are small plastic pieces that are less than 5mm in size and insoluble in water

The microplastics in UPFs could also be fueling a rise in dementia, researchers of a separate study believe.

A study from earlier this year – that was not included in this week’s article review – analyzed brain tissue from 54 autopsies and discovered every brain had microplastics in it – equivalent in mass to a plastic spoon. 

The researchers found individuals diagnosed with dementia exhibited up to 10 times more microplastics in their brain tissue compared to those without this condition. 

Although the study does not directly connect them, it does show a relationship between the accumulation of microplastics and neurological disorders. SAYS WHO

An author of that study said microplastic levels in the human brain have increased by 50 percent over the past eight years – and rates of dementia have also increased, with cases expected to nearly double by 2030. 

Microplastics can cross the blood-brain barrier, a protective shield that typically prevents harmful substances from entering the brain. 

Once inside, these tiny particles may trigger inflammation, disrupt neurological signaling, and potentially contribute to the development of neurological disorders. 

While scientists are still investigating the direct impact of microplastics on human health, animal studies have shown that exposure can lead to behavioral changes, memory impairment, and reduced motor coordination. 

Another separate 2022 study found people who ate the most UPFs had a 25 percent faster rate of executive function decline and a 28 percent faster rate of overall cognitive impairment compared to people who are the least amount of processed food.

Researchers believe the high content of sugar, salt and fat in UPFs promotes harmful inflammation throughout the body, including the brain, which could harm cognition and memory. 

Another neurological condition on the rise that could be tied to microplastics in UPFs is autism, which affects one in 31 kids in the US. This is a dramatic increase from one in 150 children two decades ago.

Researchers have posited UPFs can negatively impact the gut microbiome, and an off-balance microbiome has often been often in children with autism.

There is also some evidence UPFs can alter gene expression that leads to changes in brain development and function. 

Processed foods can also be high in levels of heavy metals, including mercury and lead, which may contribute to or exacerbate symptoms of autism.

There is no known cause of autism.   

While preliminary research has been conducted on the association of microplastics and autism, scientists say there is not enough information to draw conclusions and more research needs to be done. 

To address the issue of microplastics, the authors of the most recent article proposed the Dietary microplastic Index (DMI). A system that would quantify exposure to microplastics through food consumption and assess the microplastic content and risk of accumulation based on the foods people eat. 

Dr Stefan Bornstein, who authored a peer-reviewed research paper on removing microplastics from the body, said: ‘While we need to reduce our exposure to microplastics through better food choices and packaging alternatives, we also need research into how to remove these particles from the human body.’

In his paper, he posits that a process called apheresis could remove microplastics from the body. This is a medical procedure that removes specific components of blood from the body – like plastics – and returns the remaining components – such as the building blocks that make up blood.