Study Links Ultra-Processed Foods to Higher Risk of Early Parkinson’s Symptoms

A new study has found that consuming a diet high in super-processed foods may negatively impact your brain health. 

The research, published in Neurology, suggests that people who regularly consume packaged snacks and sweetened beverages are more likely to show very early signs of Parkinson’s disease, a neurodegenerative condition characterized by movement problems.

The finding adds to growing evidence suggesting ultra-processed foods—which have been significantly altered from their original form to enhance palatability and shelf life—may contribute to cognitive decline, including memory, attention, and learning issues. This study, however, is the first to specifically link ultra-processed foods to the development of Parkinson’s disease.

As Health has previously reported, rates of Parkinson’s disease have been increasing rapidly—faster than what can be explained alone by an aging population. Estimates suggest cases will rise 112% worldwide by 2050.

Scientists suspect that environmental and behavioral factors are to blame—and, perhaps, one of the biggest modifiable risk factors is diet.

“What you eat today can shape your brain health decades later,” Don Thushara Galbadage, PhD, MPH, a neurodegenerative disease researcher and professor of public health at Texas Christian University, told Health.

The researchers evaluated the health data of 42,843 people, with an average age of 48, who didn’t have Parkinson’s at the start of the study. Over the course of 26 years, the participants routinely underwent medical exams and completed health questionnaires. Every few years, they filled out food diaries.

The researchers then looked at who developed early signs of Parkinson’s disease. Roughly one-third of people with Parkinson’s disease experience a “prodromal phase” and develop a range of non-motor symptoms well before the classic motor symptoms appear, including:

• Constipation
• Depressive symptoms
• Body pain
• Impaired color vision
• Excessive daytime sleepiness
• Problems with sleep and smelling

In fact, constipation is one of the first prodromal signs and, according to research, can occur up to 20 years before the first motor symptoms.

The research team also calculated the amount of packaged sweets, snacks, sauces, spreads, artificially sweetened beverages, animal-based products like hot dogs, and other ultra-processed foods the participants consumed.

The results: People who ate 11 or more servings daily of ultra-processed foods—like a single can of soda, an ounce of potato chips, or a single hot dog—faced a 2.5-fold higher risk of having three or more signs of early Parkinson’s disease compared to those who ate three processed foods a day.

In addition, the more processed foods people ate, the more likely they were to develop any early signs (the one exception being constipation).

“This indicates that the food we eat can help in preventing the early symptoms of Parkison’s disease before an actual diagnosis is made,” Mary Ann Picone, MD, a neurologist and the medical director at Holy Name Medical Center’s Multiple Sclerosis Center, told Health.

The researchers emphasize that they found an association between processed foods and Parkinson’s disease, not a causal relationship. Furthermore, there may be some inaccuracies, as the participants self-reported their diets and may have underestimated or overestimated the number of processed foods they consumed.

At the moment, that’s exactly what scientists are trying to understand. The answer, according to the researchers, is likely complex and multifactorial.

Additives like artificial sweeteners may increase oxidative stress, evidence suggests.

Processed foods may also alter the gut microbiome, the community of microorganisms in the intestines, paving the way for Parkinson’s disease. “There is a strong connection between healthy bacteria in the gut and decreased inflammation noted in the brain,“ said Picone.

Additionally, overly processed foods may lead to neuron damage and increased inflammation, including in the brain. “Over time, this can accelerate neurodegenerative changes,” said Galbadage.

Together, he added, these changes may increase the risk of neurologic conditions like Parkinson’s disease, as well as:

• Dementia
• Cognitive decline
• Mood disorders
• Sleep disruptions

“The same underlying pathways, like chronic inflammation and metabolic stress, are believed to contribute,” said Galbadage.

Ultra-processed foods may affect other bodily systems, too, and contribute to cardiovascular diseases, metabolic dysfunction, and obesity, research shows.

The findings suggest it’s worth looking at how many processed foods you eat daily. Modifying risk factors, such as unhealthy eating, early on could delay symptom onset.

“Shifting from a fast-food-heavy diet to more whole, nutrient-rich foods during the prodromal phase could be a critical strategy in slowing disease progression,” Galbadage said.

The study didn’t single out one ingredient or additive to look out for but instead concluded that many different types of ultra-processed foods, from condiments to yogurt, were linked to a greater risk of Parkinson’s.

“It is not just about what we should be eating but what we should not be eating that matters, too,” Jessica Ng, MD, a neurologist with Stanford Medicine, told Health.

She hopes the findings change how doctors counsel patients and encourage people to adopt healthy eating patterns, such as the Mediterranean and MIND diets. 

Galbadage said you can start small by swapping a packaged snack for a piece of fruit or choosing water over soda. In general, he recommends opting for meals made from whole, minimally processed ingredients. When in doubt, he advised avoiding foods that come in a crinkly wrapper with a long list of ingredients.

Picone encourages her patients to stick to the perimeter of the grocery store. That’s “where you are likely to find fresh produce, meats, fish, and dairy rather than the middle where the packaged foods are located,” she said.

Added Galbadage: “Cutting back on these foods is a simple but powerful way to protect long-term brain health.”