A frequently suggested blog topic is the role of nutrition in the management of Parkinson’s disease (PD). (Feel free to suggest your own topic). For a general overview of nutritional tips for someone with PD, I encourage you to view an excellent APDA webinar entitled Living Well Every Day, that is archived on our website. The webinar presents strategies, based on firm scientific evidence, that help support a healthy lifestyle for people with PD.

For the past two weeks, I have been addressing nutritional issues as they relate to PD. In Part One of the series, I addressed whether or not to avoid particular foods/supplements based on what we currently know (or don’t know.)  Part Two focused on whether or not to take particular foods/supplements based on what we currently know (or don’t know). Today I will address diets that are sometimes suggested for people with PD (and that are also currently quite popular among people with and without PD) and I’ll discuss what we know and don’t know about their relationship to PD.

To cut to the chase, there is no one diet that is recommended for people with PD. However, the following specific diets are often asked about:

*As always, be sure to talk to your healthcare team before making and significant changes to your diet.

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Popular Diets and their effect on those with Parkinson’s disease

Gluten-free diet

The internet is full of claims that people with PD can benefit from a gluten-free diet. Many of these claims refer to a case report in which a man with signs and symptoms of PD but without gastrointestinal issues was found to have an unexplained folate deficiency, which led to a diagnosis of celiac disease. The treatment of celiac disease is adherence to a diet without gluten. Following a gluten free diet improved this man’s vitamin deficiency and his PD symptoms.

There is a wide constellation of other symptoms that can be caused by celiac disease including diarrhea, constipation, bloating, stomach cramping, fatigue, osteoporosis, and joint pain. Some of these symptoms are also common in people with PD and it would not be unreasonable to test for celiac disease in people with PD who have these symptoms. If vitamin deficiencies are found and malabsorption from the gut is suspected, then testing for celiac disease makes sense as well. Diagnosis of celiac disease can be made via a blood test to see if particular antibodies are found, followed by an endoscopy with biopsy to see if there is damage to the wall of the small intestine.

If a person is discovered to have celiac disease, then by all means he or she should follow a gluten free diet. The medical literature does not suggest however, that everyone with PD should adhere to a gluten-free diet without additional investigations. If you are concerned that you have symptoms suggestive of celiac disease, discuss them with your general doctor or neurologist who can order the appropriate testing if warranted. Otherwise, there is no need to go gluten free.

Ketogenic diet

A ketogenic diet is a high fat, moderate protein and very low carbohydrate diet that forces the body to burn fat as opposed to carbohydrates. It is used clinically to control seizures in children with very difficult-to-control epilepsy.

There have also been some studies to suggest that the ketogenic diet may have a neuroprotective effect, which led to the interest in studying the diet in PD. A recent study compared a low fat versus a ketogenic diet in PD. Interestingly, both diets resulted in improvement of motor scores, whereas the ketogenic diet showed improvement in non-motor scores as well.

It must be noted that the ketogenic diet is very restrictive and therefore very difficult to follow. In addition, it can pose health risks as well, especially to the elderly. It requires ingestion of high levels of fat which is linked to increased cholesterol and heart disease. It also requires a very limited ingestion of foods such as fruits and grains – foods that provide nutrients and fiber. With such a limited array of permissible foods, there is a risk of nutrient deficiencies. Constipation, which is often a non-motor feature of PD can be exacerbated as well with a ketogenic diet. Because of the restrictive nature of the diet, it can lead to weight loss, an effect that is not typically desired in the PD population which can have difficulty maintaining weight.

At this point, more data is needed about the benefits of the ketogenic diet for PD to determine if they outweigh the potential risks.

Mediterranean diet

A Mediterranean diet is a diet traditionally eaten in Mediterranean countries characterized by large amounts of plant-based foods including vegetables, fruits, whole grains, legumes and nuts, moderate amounts of low-fat proteins such as chicken and fish, and fats centered around olive oil.

The Mediterranean diet has been shown to lower the risk of heart disease. Studies have also shown an association between the Mediterranean diet and a lower risk of developing Alzheimer’s disease as well as . A recent study demonstrated that adherence to a Mediterranean diet is also related to a lower probability of developing prodromal PD. Prodromal PD refers to a clinical situation at which an individual does not meet the motor criteria of PD, but does have a constellation of non-motor features (including REM behavior sleep disorder, constipation, depression and anxiety) that indicate a higher than average risk of developing motor PD in the future. This finding is intriguing as it may suggest that following a Mediterranean diet could delay the onset of PD.

Although more research is needed to understand the relationship between the principles of the Mediterranean diet and PD risk, its association with brain health and good health in general, makes it a good diet to model when considering food choices for someone with PD.

The MIND diet

Some proponents of brain health suggest a hybrid of the Mediterranean diet and the DASH (Dietary Approaches to Stop Hypertension) diet which together is referred to as the MIND diet (The Mediterranean-DASH Intervention for Neurodegenerative Delay). The MIND diet has been associated with a lower risk of Alzheimer’s disease as well as lower risk and slower progression of parkinsonism in the elderly. Practically, there is much similarity and overlap between the Mediterranean and MIND diets.

The MIND diet is based on ten food groups to eat and five to avoid. The ten to eat include:

• Green leafy vegetables
• All other vegetables
• Berries
• Nuts
• Olive oil
• Whole grains
• Fish
• Beans
• Poultry
• Wine (no more than one glass a day)

The five to avoid are:

• Butter/margarine
• Cheese
• Red meat
• Fried foods
• Sweets

These principles are very similar to the Mediterranean diet and the MIND diet is another reasonable model to follow for someone with PD.

Tips and Takeaways

• There is no one diet that is proven best for people with PD.
• If a person has celiac disease and PD, they should follow a gluten-free diet. Discuss with your neurologist or primary care doctor to determine if you should be tested for celiac disease. If you do not have celiac disease, there is no evidence that a gluten-free diet is necessary.
• Due to the potential risks and the very restrictive nature of the diet, more data is needed before a ketogenic diet for PD can be recommended.
• The Mediterranean diet, which is rich in plant-based foods and olive oil has shown both heart and brain health benefits and is associated with lower rates of PD.
• The MIND diet is also a reasonable diet for someone with PD to follow.
• Talk to your healthcare team about your nutrition concerns and work together with them to ensure you are following a dietary plan that is best suited for you and your particular needs.