Researchers looked at 29 large studies involving over 1.3 million people to understand how different foods might affect the chances of developing Parkinson’s disease. They found that eating lots of dairy products like milk and cheese may slightly increase risk, while eating legumes and nuts appears to lower it. Following a healthy diet overall was linked to a 37% lower risk of Parkinson’s disease. The study suggests that what we eat plays an important role in brain health, though more research is needed to fully understand these connections.

The Quick Take

  • What they studied: Whether eating certain foods or following specific eating patterns affects the risk of developing Parkinson’s disease, a brain condition that affects movement and coordination.
  • Who participated: Over 1.3 million people from 29 different long-term studies across multiple countries. Researchers followed these people over many years to see who developed Parkinson’s disease and what they ate.
  • Key finding: People who ate the most dairy products had about 26% higher risk of Parkinson’s disease compared to those who ate the least. However, people who followed healthy eating patterns had 37% lower risk. Eating beans, nuts, and legumes appeared protective.
  • What it means for you: If you’re concerned about Parkinson’s disease risk, focusing on overall healthy eating patterns—with plenty of vegetables, fruits, whole grains, and legumes—may be beneficial. However, this doesn’t mean you must avoid dairy entirely; the findings suggest moderation may be wise, especially for milk. Talk to your doctor about your individual dietary needs.

The Research Details

This was a meta-analysis, which means researchers combined results from 29 different long-term studies to find patterns. Each of these studies followed thousands of people for many years, recording what they ate and tracking who developed Parkinson’s disease. The researchers looked at how much of each food people ate and compared disease rates between those who ate the most versus the least.

The scientists used special statistical methods to look for dose-response relationships—basically, whether eating more of something increased or decreased risk in a predictable way. They also separated results by sex to see if men and women showed different patterns. All studies included were prospective cohort studies, meaning researchers followed healthy people forward in time rather than looking backward at people who already had the disease.

This approach is powerful because it combines evidence from many studies, making the findings more reliable than any single study. By looking at actual eating patterns in real people over many years, researchers can spot connections that might not show up in shorter studies. The dose-response analysis helps determine whether small amounts of a food have different effects than large amounts.

The researchers used a standard tool called the Newcastle-Ottawa scale to check the quality of each study they included. They only included studies that followed people forward in time (prospective studies), which is stronger evidence than studies that look backward. The large number of participants (over 1.3 million) makes the findings more reliable. However, because people self-reported what they ate, there’s always some room for error in dietary information.

What the Results Show

The analysis revealed surprising findings about dairy products. People who consumed the most dairy had a 26% increased risk of Parkinson’s disease compared to those who ate the least. Low-fat dairy showed a 30% increased risk, and milk specifically showed a 23% increased risk. For every additional cup of milk per day, risk increased by about 13%. For every additional 100 grams of dairy per day (roughly 3.5 ounces), risk went up by 5-7%.

In contrast, legumes and nuts showed protective effects. People who ate the most legumes and nuts had a 29% lower risk compared to those who ate the least. When researchers looked at overall eating patterns, those who followed healthy diets (rich in vegetables, fruits, whole grains, and legumes) had a 37% lower Parkinson’s risk. Those who followed unhealthy dietary patterns had a 40% increased risk.

Interestingly, the dairy-risk connection was stronger in men than in women. Men showed much stronger associations between dairy consumption and Parkinson’s risk, while women’s risk increased less noticeably. The researchers found both linear relationships (more dairy = more risk in a straight line) and some nonlinear patterns, suggesting the relationship is complex.

Cheese showed a 4% increased risk per 10 grams consumed daily. Yogurt showed some increased risk in men but not in women. The healthy dietary pattern finding was particularly striking—it included diets rich in vegetables, fruits, whole grains, legumes, and fish while low in red meat and processed foods. The unhealthy pattern included processed foods, red meat, and refined grains. Both patterns showed dose-response relationships, meaning the more strictly people followed either pattern, the stronger the effect.

Previous smaller studies had suggested connections between diet and Parkinson’s disease, but results were mixed. This comprehensive analysis confirms and strengthens those findings. The dairy-Parkinson’s connection is particularly interesting because dairy is usually considered part of a healthy diet due to calcium and vitamin D content. This study suggests that while overall healthy eating patterns protect against Parkinson’s, dairy products may be an exception—or at least should be consumed in moderation. The protective effect of legumes and nuts aligns with previous research on plant-based foods and brain health.

The main limitation is that people reported their own eating habits, which can be inaccurate. People might forget what they ate or estimate portion sizes incorrectly. The studies came from different countries with different food supplies and preparation methods, which could affect results. Parkinson’s disease develops slowly, so it’s hard to know exactly when it started or whether diet years earlier was most important. The studies couldn’t prove that dairy causes Parkinson’s—only that there’s an association. Other factors like genetics, exercise, and environmental exposures also play roles in Parkinson’s development. Additionally, the reasons why dairy might increase risk aren’t fully understood.

The Bottom Line

Based on this evidence, consider emphasizing whole plant foods, legumes, nuts, vegetables, and fruits in your diet while moderating dairy intake, particularly milk. This aligns with Mediterranean and DASH diet patterns, which showed protective effects. However, don’t eliminate dairy entirely—calcium and vitamin D are important for bone health. Instead, aim for moderation and consider alternative sources like fortified plant-based milks, leafy greens, and supplements if needed. These recommendations are moderate-to-strong based on the large sample size, though more research is needed to understand why dairy shows this association.

This research is most relevant for people with family history of Parkinson’s disease, those over 60 (when Parkinson’s typically appears), and anyone interested in brain health through nutrition. It’s also important for healthcare providers counseling patients about disease prevention. However, people with calcium deficiency, osteoporosis, or other conditions requiring adequate dairy should discuss individual needs with their doctor. This research shouldn’t cause alarm in current dairy consumers but rather encourage thoughtful dietary choices.

Parkinson’s disease develops over many years, so dietary changes would need to be maintained long-term to potentially see benefits. Don’t expect immediate changes—brain health improvements from dietary modifications typically take months to years to manifest. The studies followed people for many years, suggesting that consistent eating patterns over time matter more than short-term changes.

Want to Apply This Research?

  • Track daily dairy intake (cups of milk, ounces of cheese, servings of yogurt) alongside weekly legume and nut consumption (servings per week). Monitor overall diet quality by tracking adherence to healthy eating patterns—count daily servings of vegetables, fruits, whole grains, and legumes.
  • Set a specific goal like ‘reduce milk to 1 cup per day’ or ‘add 3 servings of legumes weekly’ rather than making vague changes. Use the app to log meals and receive feedback on whether you’re moving toward a healthier overall pattern. Create reminders for legume-based meals and track substitutions (like plant-based milk alternatives).
  • Review dietary patterns monthly rather than daily, since the protective or risk effects develop over long periods. Track trends in overall diet quality scores rather than obsessing over individual foods. Consider periodic check-ins with a dietitian to ensure nutritional needs are met while adjusting dairy intake.

This research shows associations between diet and Parkinson’s disease risk but does not prove that dairy causes Parkinson’s or that dietary changes will prevent it. Parkinson’s disease is complex and involves genetics, age, and environmental factors beyond diet. This information is for educational purposes and should not replace professional medical advice. If you have concerns about Parkinson’s disease risk or are experiencing symptoms, consult with a healthcare provider or neurologist. Before making significant dietary changes, especially if you have existing health conditions or take medications, discuss with your doctor or registered dietitian to ensure your nutritional needs are met.