No one diet (or exercise or medication regimen) will suit everyone with Parkinson's disease (PD) and no specific combination of foods has been proven to slow the progression of PD. Simply put, there is no single "Parkinson's diet." Doctors do however recommend a healthy, balanced diet that includes a variety of fruits and vegetables. Proper nutrition is important for people with PD. It can maximize general health and help ease certain non-motor symptoms, such as constipation and low blood pressure. And for some people, dietary adjustments (particularly around protein intake) may ensure PD medications, such as levodopa, work optimally.

(Read more and watch a video about diet and Parkinson's.)

Here we discuss a few of the specific diets about which we often get questions. Be sure to discuss any plans to change your eating habits with your personal physician and registered dietitian, if you have one. (Your doctor can refer you to a dietitian, or you can search online for one in your area.)

Ketogenic Diet
The ketogenic diet is high in fat and low in carbohydrates and protein. Reliance on this diet forces the body to shift its usual energy source from glucose (sugar) to fats, or ketone bodies, which some believe are a more "efficient" fuel.

The diet has been used to treat medication-resistant epilepsy for many years and pre-clinical work supports its potential use in Parkinson's.¹ As for mechanisms of benefit in PD, researchers posit that ketone bodies work as antioxidants and bypass a defect in the mitochondria (the cells' powerhouses) to fuel the body's energy production.² (MJFF also supported pre-clinical work to evaluate whether the ketogenic diet could decrease alpha-synuclein, the sticky protein that clumps in the brains of people with PD.)

Use of this diet in people with Parkinson's is limited to anecdotal reports and one case study in which five volunteers followed a ketogenic diet for 28 days. Trial participants had an improvement in their ability to perform daily activities and their motor symptoms, but a placebo effect could not be ruled out.³ It's also worth mentioning that since the ketogenic diet is low in protein, which interferes with the absorption of levodopa, some benefit could perhaps be attributed to improved levodopa absorption rather than an effect on the brain per se. (Read more about the interaction between levodopa and protein.)

A physician and dietitian must help implement this diet, monitor bloodwork and evaluate for side effects, including dehydration, low glucose and kidney stones. It's a strict regimen that can be tough to follow and could put you at risk for certain nutritional deficiencies.⁴ Modified forms of this diet include the Atkins and Grain Brain regimens. (Both emphasize higher fat and lower carbohydrate consumption but they differ in the types of recommended fats.)

Gluten-free Diet
The gluten-free diet excludes the protein gluten, which is found in wheat, barley and rye. In people who have celiac disease, gluten sensitivity or a gluten allergy, this protein can cause inflammation in the gastrointestinal tract (with accompanying abdominal bloating, nausea and diarrhea). It also could lead to non-specific symptoms, such as headaches, joint pain, and even mood and memory changes.

At this time, no pre-clinical or clinical evidence exists to support the use of a gluten-free diet for Parkinson's disease. Still, some individuals with Parkinson's who try this diet report benefit on certain symptoms, and one man who had "silent celiac disease" experienced significant improvement in his PD when gluten was removed from his diet.⁵ Sticking to this diet can be difficult and may put you at risk of certain vitamin deficiencies.

Mediterranean Diet
The Mediterranean diet focuses on fruits, vegetables, legumes and whole grains. For protein, fish is a staple; dairy and poultry are relied upon less heavily and red meat is to be consumed a few times per month at most. The diet stresses intake of "healthy fats," such as those in nuts and olive oil. Red wine, in moderation and generally with meals, is an option.

This diet is linked to lower levels of low-density lipoprotein (LDL) cholesterol, and has been associated with decreased risk for Alzheimer's dementia, heart disease and certain forms of cancer. A 2007 population study showed this diet was correlated with a lower risk of PD.⁶ A 2012 case-control study corroborated this and demonstrated the diet may delay the age of onset in people with Parkinson's. It may be that this diet exerts anti-inflammatory and/or antioxidant effects, but further research is necessary to evaluate potential mechanisms and benefits in PD.⁷

MIND (Mediterranean-DASH Intervention for Neurodegenerative Delay) Diet
The MIND diet is a combination of the Mediterranean and DASH (Dietary Approaches to Stop Hypertension) diets. It emphasizes 10 foods -- leafy greens, other vegetables, berries, poultry, fish, olive oil, beans, nuts, whole grains and wine -- in specific recommended daily and weekly amounts.

This diet has been associated with lower rates of Alzheimer's dementia, but hasn't been specifically studied in Parkinson's.⁸

Key Takeaways

• There is no single "Parkinson's diet." 
• Dietary recommendations should be based on an individual's medical conditions and medications, activity level, etc. 
• Treat diet like medication -- don't make significant changes without first discussing with your physician and dietitian. 
• Additional research is necessary to understand more about the basic mechanisms of these diets and how they could benefit symptoms and potentially disease progression in PD. 

Read MJFF's guide to diet and Parkinson's.

* NOTE: The medical information contained in this article is for general information purposes only. The Michael J. Fox Foundation has a policy of refraining from advocating, endorsing or promoting any drug therapy, course of treatment, or specific company or institution. It is crucial that care and treatment decisions related to Parkinson's disease and any other medical condition be made in consultation with a physician or other qualified medical professional.

References

1. Shaafi S, Najmi S, Aliasgharpour H et al. The efficacy of the ketogenic diet on motor functions in Parkinson's disease: A rat model. Iran J Neurol. 2016 Apr 3; 15(2): 63-9. 
2. Gasior M, Rogawski M and Hartman A. Neuroprotective and disease-modifying effects of the ketogenic diet. Behav Pharmacol. 2006 Sep; 17(5-6): 431-9. 
3. VanItallie TB, Nonas C, DiRocco A et al. Treatment of Parkinson disease with diet-induced hyperketonemia: A feasibility study. Neurol. 2005 Feb; 64(4): 728-30. 
4. Hartman A and Vining E. Clinical aspects of the ketogenic diet. Epilepsia. 2007 Jan; 48: 31-42. 
5. Di Lazzaro V, Capone F, Cammarota G et al. Dramatic improvement of Parkinsonian symptoms after gluten-free diet introduction in a patient with silent celiac disease. J Neurol. 2014 Feb; 261(2): 443-5. 
6. Gao X, Chen H, Fung T et al. Prospective study of dietary pattern and risk of Parkinson disease. Am J Clin Nutr. 2007 Nov; 86(5): 1486-1494. 
7. Alcalay R, Gu Y, Mejia-Santana H et al. The association between Mediterranean diet adherence and Parkinson's disease. Mov Disord. 2012 May; 27(6): 771-4. 
8.  Morris M, Tangney C, Wang Y et al. MIND diet associated with reduced incidence of Alzheimer's disease. Alzheimers Dement. 2015 Sep; 11(9): 1007-1014.