People who regularly eat ultraprocessed foods have nearly triple the risk of developing Parkinson’s disease, a study suggests.

Research conducted by Chinese scientists revealed that individuals consuming 11 or more servings of ultraprocessed foods daily were 2.5 times more likely to show early indicators of Parkinson’s disease, a progressive movement disorder, compared to those who ate three or fewer servings. 

However, even three or fewer raised the risk by up to 60 percent, depending on the specific food.

One serving includes items like a can of soda or a tablespoon of ketchup; however, foods typically deemed healthy, such as salads and sliced meats, can also fall into the ultraprocessed category. 

The earliest signs of Parkinson’s disease in the study included sleep issues, fatigue, constipation and a reduced ability to smell. 

These symptoms come before tell-tale signs like tremors and balance issues and can start decades before diagnosis. 

In a recent medical journal article, the researchers proposed that artificial additives in these foods, such as emulsifiers, sweeteners, and preservatives, might trigger inflammation and oxidative stress. This harms neurons in the brain responsible for dopamine production, a neurotransmitter essential for movement control. 

Additionally, the foods quickly get absorbed into the bloodstream and attack the microbiome, a community of ‘friendly’ bacteria that live in the gut and communicate with the brain. Harmful bacteria creates inflammation in the brain that destroys dopamine-producing neurons. 

The experts believe cutting down on ultraprocessed food consumption may slash the risk of developing Parkinson’s years or decades before it would be diagnosed. 

Researchers in China found consuming 11 servings of ultraprocessed foods per day raised the risk of developing early Parkinson’s signs by 2.5 times (stock image)

Symptoms of Parkinson’s include uncontrollable tremors, slow movements and muscle stiffness

Outside researchers, however, cautioned that these early signs are not definitive indicators a patient will go on to develop Parkinson’s. 

Dr Xiang Gao, study author from Fudan University in China, said: ‘Eating a healthy diet is crucial as it has been associated with a lower risk of neurodegenerative diseases and the dietary choices we make today can significantly influence our brain health in the future.

‘There’s growing evidence that diet might influence the development of Parkinson’s disease. Our research shows that eating too much processed food, like sugary sodas and packaged snacks, might be speeding up early signs of Parkinson’s disease.’

Parkinson’s is diagnosed in about 90,000 Americans every year and is caused by the death of nerve cells in the brain that produce dopamine, which controls movement.

The condition is also on the rise in the US and UK, which is thought to be caused by a rapidly aging population, environmental toxins and lifestyle choices like smoking.

In the UK, there are about 18,000 new diagnoses every year in people 45 and older.  

Parkinson’s disease is a progressive movement disorder in which the brain can’t produce enough dopamine, a neurotransmitter that controls movement. A lack of dopamine leads to issues like tremors, falls, trouble swallowing and mobility issues.

The new study, published Wednesday in the journal Neurology, followed 42,853 people who did not have Parkinson’s at the start of the study. They were then followed for up to 26 years.

Participants underwent regular medical appointments and filled out diaries every two to four years detailing what they ate and how often. 

Researchers divided foods into four categories: unprocessed or minimally processed foods, processed culinary ingredients, processed foods and ultraprocessed foods. 

Ultraprocessed foods included were: sauces, spreads, or condiments; packaged sweets; snacks or desserts; artificially or sugar-sweetened beverages; animal-based products; yogurt or dairy-based desserts; and packaged savory snacks.

One serving was considered one can of soda, one ounce of potato chips, one slice of packaged cake, one hot dog or one tablespoon of ketchup. 

Early Parkinson’s symptoms evaluated were sleep behavior disorders, constipation, depressive symptoms, body pain, impaired color vision, excessive daytime sleepiness and reduced ability to smell.

The researchers found consuming 11 servings of ultraprocessed foods every day raised the risk of developing at least three early Parkinson’s symptoms by 2.5 times compared to people who consumed three or fewer servings. 

Additionally, even three or fewer servings raised the risk. Sauces and condiments had the smallest increase at 17 percent while packaged sweets raised the risk 60 percent.  

Dr Gao said: ‘Choosing to eat fewer processed foods and more whole, nutritious foods could be a good strategy for maintaining brain health.

‘More studies are needed to confirm our finding that eating less processed food may slow down the earliest signs of Parkinson’s disease.’

The researchers believe additives in ultraprocessed foods like emulsifiers and sweeteners promote oxidative stress, an imbalance between disease-fighting antioxidants and harmful free radicals.

Free radicals attack the body’s cells and tissues. In Parkinson’s disease, they damage neurons that produce dopamine, a neurotransmitter that regulates movement. 

Actor Michael J Fox (pictured here) was diagnosed with Parkinson’s disease at just 29 years old. He now advocates for more research into the condition

Ultraprocessed foods are also thought to induce inflammation in the brain, which further attacks the neurons responsible for dopamine production.

The study’s main limitation was that participants self-reported their ultraprocessed food intake, so it’s possible they may not have accurately calculated or remembered how many servings they had. 

Dr Katherine Fletcher, research lead at Parkinson’s UK, said: ‘Research into diet in general is difficult as people often will inaccurately self-report what their diet comprises. This could be down to forgetting to fill in the diary at the time, to subjective interpretation of amounts of UPFs.

‘The study group also lacked ethnic and socio-economic diversity, which is vital when looking to better understand factors that contribute to the causes of a health condition.’

Dr Daniel J van Wamelen, clinical senior lecturer in neuroscience and Honorary Consultant Neurologist at King’s College London, noted while the results are ‘interesting,’ more definitive research is still needed.  

He said: ‘It is important to highlight that the symptoms examined in this study are possible early signs of Parkinson’s disease, not definitive indicators that someone will go on to develop it. The study did not track whether participants were diagnosed with Parkinson’s later on.

‘Many of the individual symptoms noted, such as sleep disturbances, constipation, and mood changes, are common in the general population. While the study found that people who ate more ultra-processed foods tended to report more of these non-motor symptoms, it did not find a direct increase in the risk of Parkinson’s disease itself. 

‘The connection to Parkinson’s disease should be viewed with caution until more definitive evidence becomes available.’