Dr Laurie Mischley investigates how the PRO-21 diet correlates with a slower progression of Parkinson's symptoms to help maintain quality of life

Parkinson's is frequently described as a condition that progresses over time. However, a clinical study from a research team in Seattle, USA, led by Dr Laurie Mischley, indicates that a targeted dietary plan may help slow this negative progression. The findings offer a practical avenue for proactive lifestyle changes, demonstrating a measurable link between specific nutritional habits and an extended number of years with a good quality of life. This comprehensive overview of the research comes with sincere thanks to community member Mogens Weinreich for writing up these insights, bringing them to our attention, and encouraging wider participation in the ongoing study. Dr Mischley has focused much of her career on tracking the progression of the condition. In 2017, she developed the Patient-Reported Outcomes in Parkinson's Disease scale, known as PRO-PD, which allows individuals to track 35 symptoms of the condition via an online questionnaire. Validated by the Journal of Movement Disorders, this freely available application measures quality of life, where a score below 1,000 points represents a good to excellent daily experience, whilst scores above 1,500 points indicate a poor quality of life. The data collected from participants revealed a very large variation between individuals. While some people experience rapid progression within a few years of diagnosis, others maintain a good quality of life for more than two decades. This variation prompted Dr Mischley to investigate the specific lifestyle and dietary habits associated with these differing outcomes, leading to a study published in the journal Nutrients in July 2025 titled "Beyond MIND and Mediterranean Diets: Designing a Diet to Optimize Parkinson's Outcomes". Using data from over 2,200 participants, Dr Mischley designed the PRO-21 diet, a 21-point checklist tailored specifically around the data collected from people with Parkinson's. While general diets like the MIND or Mediterranean protocols are recognized for their protective effects on brain cells and share common elements like nuts, olive oil, vegetables, and fish, the PRO-21 diet was developed to address specific dietary variables unique to this population. The data analysis suggests that every single point on the scale matters when evaluating long-term outcomes. Participants who scored between six and nine points experienced an average of 10 good years before their quality of life scores crossed the 1,000-point threshold. This timeline rose to an average of 14 years for those scoring between 10 and 14 points. Most notably, those who achieved 15 or more points by closely adhering to the dietary plan experienced an average of 18 high-quality years. The statistics suggest that high adherence to these recommendations correlates with an additional eight to ten years of well-being compared to following the guidelines sporadically. The Breakdown: What to Choose and What to Avoid The protocol emphasizes clean, nutrient-dense, plant-forward choices while highlighting items that correlate with a faster rate of symptom progression. To build up points in the encouragement category, the data points toward buying organically grown food whenever possible, primarily because organic choices are not treated with synthetic pesticides, which act as environmental toxins that should be avoided. Preparing meals from scratch at home is also beneficial, as it avoids ready-made meals that are often industrial products of varying nutritional quality. Spices should be used liberally, as they have been shown to contain many beneficial components that contribute to a nutrient-rich diet. For specific daily and weekly amounts, the diet awards points for consuming half a cup of nuts or four tablespoons of nut spread daily, two tablespoons of olive oil daily, and one cup or two medium pieces of fresh fruit daily. It also awards points for half a cup of fresh vegetables five or more times per week, four ounces of seafood or shellfish two or more times per week, eight ounces of wine two or more times per week, and eight ounces of coffee two or more times per day. Conversely, points are awarded in the avoidance category only if you have consumed the item less than once in the past month. The study highlights that land-animal meats such as pork, beef, and chicken correlate with poorer outcomes, alongside fried foods like corn chips, potato chips, French fries, and donuts. Participants also scored points for avoiding juice (defined as one eight-ounce glass), sodas whether diet or regular, and added sugar, meaning you can truthfully state "I avoid sugar". Refined grains, including pasta, bread, pastries, crusts, and crackers, are linked to faster progression, along with canned foods like tomato sauce, beans, citrus, vegetables, and soups. Artificial sweeteners such as aspartame, acesulfame K, and saccharin, which are frequently found in chewing gum and diet drinks, are also on the elimination list. Crucially, the entire family of animal dairy products, including milk, cheese, yoghurt, cream, butter, and ice cream, showed a particularly strong correlation with rapid symptom progression and should be avoided. How to Get Involved and Take Control Transitioning to a whole-food, plant-based or vegan lifestyle represents a major shift in daily habits, but the compiled data suggests a clear correlation with better long-term quality of life. While current medications focus primarily on symptom management, the PRO-21 diet offers an evidence-based lifestyle tool to help manage how the condition progresses over time. To participate and utilize these findings, you can get involved by downloading the free PRO-PD tracking app on your iPhone or Android smartphone. By tracking your symptoms, using the PRO-21 checklist to evaluate your dietary choices, and focusing on nutrient-rich options, you can actively manage your health journey. Contributing your experiences through these ongoing questionnaires also helps expand this global dataset, providing researchers with more data to refine these protocols for the wider community.