Ultra-Processed Foods in The Spotlight: Diet Linked to Early Parkinson's Symptoms

A study of more than 42,000 people showed that those who consume a lot of ultra-processed foods, such as snacks, soft drinks and ready-made meals, are more likely to show early signs of Parkinson's disease, such as constipation, sleep disorders, depression and body aches. Although the study does not prove that these foods cause the disease, it suggests that reducing consumption may help protect brain health.

Parkinson's disease is a neurological disorder that affects movement control, usually manifesting with tremors, stiffness and slowness. However, before these motor symptoms appear, many people experience non-motor signs, such as sleep disorders, constipation, depression and loss of smell, which can appear years before the official diagnosis.

This study investigated whether there is a link between frequent consumption of ultra-processed foods and early signs of Parkinson's disease.

Ultra-processed foods (UPFs) are industrial products with many artificial ingredients, such as colorings, preservatives and sweeteners, and usually include snacks, soft drinks, stuffed biscuits and frozen ready-made meals. These foods are convenient, but their frequent consumption has been linked to several health problems.

Researchers followed more than 42,000 healthy people for several years, including 25,095 women (58.6%) with an average age of 47.8 years, analyzing their eating habits and non-motor symptoms associated with Parkinson's, such as sleep disturbances, constipation, loss of smell, daytime sleepiness, body pain, difficulty seeing colors and symptoms of depression.

The results showed that those who consumed more ultra-processed foods had a significantly higher chance of experiencing three or more of these early symptoms of Parkinson's, compared to those who ate fewer of these products.

Even when the researchers analyzed only some symptoms or removed constipation from the count, the results continued to point to a strong association with high consumption of ultra-processed foods.

Furthermore, when each symptom was assessed individually, it was also noted that people who ate more of these foods had more sleep disorders, constipation, body aches and depressive symptoms.

In summary, the study suggests that a diet rich in ultra-processed products may be related to the appearance of early signs of Parkinson's disease, even before motor symptoms manifest.

Although these results do not prove a cause and effect relationship, they indicate that reducing the consumption of these foods may be an important strategy for taking care of brain health in the long term. More research will be needed to confirm this link and understand whether changing diet can help prevent the progression of the disease.

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Long-Term Consumption of Ultraprocessed Foods and Prodromal Features of Parkinson Disease

Peilu Wang, Xiao Chen, Muzi Na, Mario H. Flores-Torres, Kjetil Bjornevik, Xuehong Zhang, Xiqun Chen, Neha Khandpur, Sinara Laurini Rossato, Fang Fang Zhang, Alberto Ascherio, and Xiang Gao 

Neurology. June 10, 2025 issue 104 (11)

https://doi.org/10.1212/WNL.000000000021356

Abstract:

Consumption of ultraprocessed foods (UPFs) has been associated with a higher risk of various chronic diseases, but its relation to prodromal Parkinson disease (PD) remains unclear. We aimed to assess the association between long-term UPF consumption and nonmotor features suggestive of prodromal PD. This longitudinal analysis included participants without a history of PD from the Nurses' Health Study and Health Professionals Follow-Up Study. UPF consumption was assessed using repeated food frequency questionnaires (1984–2006) and grouped based on Nova classification. Participants provided data on probable REM sleep behavior disorder (pRBD) and constipation in 2012. Between 2014 and 2015, a subset of participants provided data on 5 additional nonmotor features, including hyposmia, impaired color vision, excessive daytime sleepiness, body pain, and depressive symptoms. The primary outcome was the combination of all 7 prodromal features and further categorized as 0 (reference), 1, 2, and ≥3 features. The secondary outcomes were all features except constipation, a combination of 3 commonly recognized features (constipation, pRBD, and hyposmia), and individual features. Multinomial logistic regression was used to estimate the association of UPF consumption with the combination of prodromal features. The association between UPF consumption and each individual feature was further examined using logistic regression. The study analyzed 42,853 participants (25,095 women [58.6%]; mean [SD] age, 47.8 [5.2] years). Comparing extreme quintiles of UPF consumption, the multivariable-adjusted odds ratio (OR) for having ≥3 vs 0 prodromal features was 2.47 (95% CI 1.89–3.23, ptrend < 0.0001) for cumulative average intake and 1.50 (95% CI 1.18–1.89, ptrend = 0.0009) for baseline intake. Similar results were observed for combinations of all features except constipation (OR 2.00, 95% CI 1.29–3.11, ptrend < 0.0001) and combinations of 3 features (OR 2.47, 95% CI 1.41–4.34, ptrend = 0.008). In addition, higher UPF consumption was associated with increased odds of individual prodromal features, including pRBD, constipation, body pain, and depressive symptoms.

Long-term UPF consumption was positively associated with nonmotor prodromal PD features. More studies are warranted to confirm whether lowering UPF consumption may prevent the occurrence of nonmotor symptoms that often precede PD diagnosis.