One popular type of food linked to early symptoms of Parkinson's disease

People who eat more such as cold breakfast cereal, biscuits and hot dogs are more likely to have early signs of disease, a study found. The neurodegenerative disease causes symptoms including involuntary shaking, slow movement, and stiff muscles. It affects around 153,000 people in the UK.

Experts looked at the diets of more than 42,000 people and whether they had signs of prodromal Parkinson's disease, which is the earliest stage. Early symptoms include constipation, , excessive daytime sleepiness and reduced ability to smell. The research found that people who ate 11 or more servings of ultra-processed foods per day were 2.5 times more likely to have three or more signs of early Parkinson's disease, compared to those who ate fewer than three servings.

Study leader Dr Xiang Gao, from Fudan University in Shanghai, , 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."

The researchers stressed that their study did not prove that ultra-processed foods caused the increased risk of early symptoms, but it showed an association.

Dr Gao added: "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 research was published online in Neurology, the medical journal of the American Academy of Neurology.

Commenting on the findings, British experts also noted that the study did not look directly at risk of being diagnosed with Parkinson's disease, just some of the early symptoms linked to it.

Professor Jules Griffin, director of the Rowett Institute at the University of Aberdeen, said it was not clear whether "it's really ultraprocessed food that is the culprit or poor diets in general".

Many ultra-processed foods are also high in saturated fat, sugar and salt, which have all been linked to an increased risk of dementia.

Prof Griffin added: "The study adds to a growing body of evidence that diet has a major role in brain health and complex brain diseases like Parkinson's, and just like we give out advice for healthy eating for type 2 and we should be doing the same for a healthy and functioning mind."

Dr Katherine Fletcher, research lead at Parkinson's UK, said: "Research into diet and nutrition is crucial, as there is growing evidence that, for some individuals, Parkinson's may originate from changes in the .

"Ongoing studies are exploring alterations in the gut microbiome in Parkinson's and investigating potential interventions to address these changes and as well as investigating diet and supplements to help manage symptoms."