Ask an Expert: Yolanda Wang, Registered Dietician, Discusses Evidence-based Nutrition for People with Parkinson’s

Yolanda is a Registered Dietitian (RD) and an American College of Sports Medicine (ACSM) certified personal trainer. As a University of British Columbia (UBC) alumnus with a Dietetics Major and Kinesiology Minor, she is passionate about working with clients to develop a healthy and satisfying lifestyle. She works on the research and program delivery side at the Brain Wellness Program (BWP) under the supervision of Dr. Silke Cresswell, providing nutrition education and cooking together with participants. Before joining the BC Brain Wellness team, she worked as a dietitian in acute care, gestational diabetes clinics, and long-term care facilities, and as a personal trainer at UBC Recreation Center. She is excited to introduce the nutrition piece to the comprehensive lifestyle and wellness projects at BWP.

Does diet impact either the symptoms or progression of Parkinson’s disease (PD)? If so, how?

Diet or food behaviours could impact certain symptoms of Parkinson’s disease, such as constipation, gas and bloating, fatigue, unintended weight loss, orthostatic hypotension (low blood pressure), and daytime sleepiness. This is done by adjusting the content, timing, and volume of food and drink depending on the specific issues the individual is facing. The considerations for content include fibre, fluid, caffeine, protein, fat etc.; the consideration for timing is mostly about scheduling the meals and snacks to avoid food-drug interaction, promote energy levels for daily activities and exercises, and promote recovery from exercises, etc.; as for food volume, it’s usually about finding the appropriate volume to ensure adequate energy, while avoid causing nausea or low blood pressure.

This is not a one-way influence, as PD could also impact food behaviours and nutrition needs in various ways. This includes reducing the food intake due to hyposmia (decreased sense of smell), hypogeusia (decreased sense of taste), depression, difficulty chewing and swallowing, delayed gastric emptying, constipation, or dementia, as well as increasing or decreasing energy output due to tremor, bradykinesia, dyskinesia, or rigidity. The accessibility of nutritious food and the ability to prepare nutrition-adequate and enjoyable meals may also be impacted. Without proper management, this will in turn, further impact the symptoms and disease progression of PD.

There’s currently no strong evidence from experimental studies supporting specific diets, food, or nutrients for the prevention or slower progression of Parkinson’s, and thus, we cannot conclude what foods or diet will reduce the risk or progression rate of PD. However, several observational studies show the associations between certain dietary patterns, especially Mediterranean and MIND diet (combines the brain-healthy foods of the Mediterranean diet and the heart-healthy elements of the DASH diet, which was created to lower blood pressure), and reduced risk or severity of PD.

Figure 1. Summary of the complex interactions of dietary patterns and food choices with socioeconomic factors, PD-related malnutrition, disease pathophysiology, symptoms and quality of life. From Tosefsky, K. N., Zhu, J., Wang, Y. N., Lam, J. S. T., Cammalleri, A., & Appel-Cresswell, S. (2024). The role of diet in Parkinson's disease. Journal of Parkinson's Disease, 14(Suppl. 1), S21–S34. https://doi.org/10.3233/JPD-230264 

What role does inflammation play in Parkinson’s, and how can diet help to reduce inflammation in the body?

The mechanism of PD development is not well understood. Experts and researchers have suggested the model of the gut-brain axis, where the disruption of the regular gut microbiome leads to local inflammation and increased gut permeability (leaky gut), which lead to systemic inflammation in the body and eventually cause neuroinflammation and neurodegeneration in the brain.

There is some indirect evidence to support the logic of the model, such as the altered gut microbiome composition, increased inflammation markers in blood circulation, and higher gastrointestinal comorbidities among people with PD. However, more research is needed to understand or prove the mechanisms.

The current evidence on dietary patterns and PD (mentioned above) aligns with this model, as Mediterranean-style diets encourage the intake of foods high in anti-inflammatory components and discourage the intake of foods considered pro-inflammatory.

How does gut health influence Parkinson’s, and are there specific dietary changes that can support a healthier gut microbiome for those with the disease?

Gut health may impact brain health through the gut-brain axis, the model mentioned above. Several studies have shown similar patterns of changes in microbiota among people with PD, which include the decrease of short-chain fatty acid-producing bacteria. Short-chain fatty acids (SCFA) play an important role in maintaining gut wall integrity. Decreased SCFA could contribute to increased gut permeability and inflammation in PD. The composition of gut microbiota was also shown to be related to certain PD symptoms, including consistency of bowel movement and constipation.

What is clear is that increased fibre intake, with proper hydration, can alleviate constipation, which may then improve nausea, low appetite, as well as medication absorption.

What is unclear (but is of interest), is the impact of dietary patterns, probiotics, or prebiotics on the composition of the gut microbiome, and its impact on PD.

Individuals with PD are advised to be careful about protein intake and medication timing. Can you explain why this is and what can be done to ensure they consume adequate protein throughout the day?

Our body uses similar mechanisms to absorb and deliver levodopa and protein. When taken around the same time, protein can impact the absorption and effectiveness of levodopa. Therefore, we usually recommend taking the levodopa-containing medication 30-60 minutes BEFORE a meal/snack with high protein, allowing the medication to be delivered to our brain or “kick-in”, and 1.5-2 hours AFTER a high-protein meal, as a balanced meal usually takes longer to digest (compared to fast-relieving medication). The length of these breaks may be longer or shorter depending on the individual’s digestion and metabolic rate. I recommend my clients to experiment with it to see the best break length between medication and high-protein food.

Our protein needs vary. The general protein recommendation for most adults is 0.8 grams per kilogram of body weight. This is not individualized advice. The protein needs as we age may increase due to reduced absorption, certain chronic diseases, and to prevent muscle wasting, but they may decrease due to certain conditions, such as kidney disease. Please consult your healthcare provider if you have concerns about protein intake.

Most people can reach their protein needs by including protein-rich food in all their meals and having balanced meals, with protein food counting for ¼ of the volume (refer to Canada's Food Guide).

For people with low appetite or who take longer to digest/absorb meals, try small frequent meals/snacks with protein that range around medication time. For example, if I have levodopa every three hours at 7, 10, 13, 16, 19, and 22 o’clock, I can have small meals or large snacks at 8, 11, 14, 17, 20, and before bed if needed. This way, we can get consistent energy and protein intake without the stress of having a large volume of food/protein all at once.

People with motor fluctuations (medication does not work predictively and effectively) may benefit from a protein redistribution diet, where individuals eat low-protein meals during the daytime when they perform most of their daily activities and have a high protein intake during evening time to reach the protein requirement of the day. This is still an effective way to ensure proper protein intake.

Are there any popular diets (i.e. keto, Paleo, Mediterranean, plant-based/vegan) that people with Parkinson’s should avoid?

From previous answers, we know that there’s no strong evidence to support a specific dietary pattern in terms of reducing the risk of Parkinson’s, apart from the general consensus on the Mediterranean, MIND diet, and diets with higher quality according to the Healthy Eating Index. These diets usually are high in fruit and vegetables, whole grains, plant-based protein, and healthy fat. While they usually recommend reduced intake of certain foods, such as red meat, sweets, and fast foods, they do not require a complete restriction of certain food groups.

Like most dietitians, I won’t recommend a client to go on a restrictive diet (a diet that eliminates one or multiple food groups) unless there is a large amount of evidence suggesting health benefits for the client’s specific condition, or the client has personally tried and benefited significantly from the diet. When deciding whether to try such a diet or not, think about the risks versus benefits. What is the evidence supporting the benefits of a diet, and what are the risks associated with such a diet? For most of the restrictive diets, evidence of their benefits on PD is scarce.

There are a few studies showing potential benefits from following a ketogenic diet on the motor and non-motor symptoms, however, these studies were done on a small group of participants, with different study designs, and have different outcome focuses. Therefore, the benefits of a ketogenic diet are inconclusive. Some potential risks with restrictive diets in general include nutrition deficiency, weight loss, disordered eating, increased time commitment, and affected social well-being. Some people living with PD may already struggle with nutrition adequacy, weight maintenance, or stress management, so a restricted diet might not be a good option in these cases.

If someone is following such a diet, I highly recommend they work with their healthcare team to check nutrition adequacy regularly.

What tips do you have for dealing with loss of appetite in people with PD, due to either symptoms or medication?

Loss of appetite could be related to loss of smell or taste, reduced motility of the digestive system, nausea, apathy, depression, or increased difficulties with eating. Depending on the cause, one may try one or a few of the suggestions below to address the issue:

• Find your motivation to eat, either to get strength for your favourite exercise, to hang out with your family, to play with grandchildren, or to maintain your activities of daily living.
• Explore the texture and presentation of the meals. We love food for more than just the smell or taste. If food becomes “boring” to you due to the lack of taste, try to include various textures (crunchy, crispy, creamy, etc.) and colours, and play with it for plating.
• Try ginger to alleviate the nausea. You can put ginger in a ginger date smoothie or pour hot water over ginger slices, perhaps with lemon juice and honey, to make ginger lemon tea.
• Have small frequent meals throughout the day. With reduced motility of the digestive system, it may take longer to digest food, which can make you feel full easily and have no appetite for more. If you can’t have a large amount in three meals, make it six small meals instead, and give your body time to digest before adding more in.
• Choose high-energy foods – especially those that are high in fat. Fat will provide more than double the energy of sugar or protein with the same amount of food. Therefore, if you get full easily or do not have the strength to eat more food, choose items such as nuts, seeds, nut butter or seed butter, avocado, vegetable oil, full-fat dairy instead of low-fat, or even ice cream! Some of these might not usually be considered “healthy”, however, if you are suffering from rapid weight loss, then these would be “healthier” for you than low-energy foods for weight maintenance purposes.
• Try nourishing fluids, such as smoothies, blended soup, milk or milk alternatives, and oral nutrition solutions (Boost or Ensure). If chewing takes too much effort, fluids might go down easier than solid food. Making sure you are getting the nutrients and energy you need from fluids is an efficient way to get both hydration and nutrition checked.
• You can also try your favourite foods: anything that you can eat works! This could be ice creams, chocolate, pudding, or mashed potatoes, etc.

Do you recommend any dietary supplements for people with Parkinson’s? If so, which ones?

There’s not enough evidence to support the general recommendation of vitamin or mineral supplements. This does not mean that no nutrition supplement will help. We just haven’t found any. People may have heard or read anecdotal stories about how other people living with PD benefit from XX supplement. It might be true for them, and it may or may not work for you. Again, I don’t actively recommend any vitamin or mineral supplement, unless I know the person is deficient or at risk of deficiency, yet cannot meet the needs by food alone (food restriction, low food intake, impact absorption, etc.). In those cases, the supplement can be helpful and essential.

For other clients, if they have a supplement of interest, I would share the information I know on the supplement (or refer them to a pharmacist), explain any potential risk, and let them decide whether to try it or not. Some clients like to experiment on themselves with supplements; if it’s within the safe dosage, and if purchasing the supplement does not cause a financial burden, then it is their personal choice, and I will not intervene. It is recommended to check with their doctor before taking any new supplement to avoid drug interactions.

Older adults may be at higher risk for certain nutrition deficiencies, such as vitamin B12, folate, vitamin D, iron, etc. If you suspect you may be at risk, ask your doctor for a relevant test. If the results show a deficiency or overload, work with your healthcare team to adjust your diet or supplement accordingly.

What are the best dietary strategies to help deal with fatigue and low energy levels that are often experienced by people with Parkinson’s?

• Snacks between meals – eat every two to three hours for a consistent supply of energy (avoid protein around levodopa intake, still enjoy food with more sugar and fat – like fruit, crackers with creamy dip, etc.).
• Adequate protein intake to sustain muscle mass and maintain strength.
• A moderate amount of caffeine as a central nervous system stimulant. This may help with sleepiness during the day and increase workout performance if taken before exercise.
• Simple sugar for a quick energy surge. Although foods with complex carbohydrates (such as whole grains, fruits, and vegetables) are recommended for stable blood sugar and a consistent source of energy, there are times when we need a fast energy source, such as before an intense workout or during or after a long hike.

There are so many opinions about diet and nutrition, especially in our ever-connected digital world. How can people with Parkinson’s ensure they are receiving high-quality, evidence-based information about this topic?

Look for reliable sources, such as government websites, relevant organizations, and people with valid credentials, such as registered dietitians.

You can also look for information that is backed up with peer-reviewed papers. However, this cannot guarantee that the information is not biased, as a lot of nutrition-related topics are controversial, and studies may have conflicting results. One paper may not tell you the whole truth.

Would you recommend people with PD work with a dietician? If so, how can they get connected to resources and dieticians in their community?

People who live with PD and have diet or nutrition-related issues or questions could benefit from talking to a dietitian. However, there are also many people living with PD who already have their own dietary routine that works really well for them and may not need a dietitian’s consultation. If you are unsure, you are always welcome to talk to an RD and figure it out. You can also complete a validated nutrition screener to see if you are at malnutrition risk (see the Screen-8 tool at https://bit.ly/screen8tool and the Screen-14 tool at https://bit.ly/screen14tool. Guides on how to use these tools may be found at https://bit.ly/nutritionscreenguides).

• For free one-on-one nutrition counselling for people living with PD in BC from the BC Brain Wellness Program (self-referral form - priority given to those with higher nutrition risks), visit: https://bit.ly/BWPnutritioncounselling 
• For group nutrition and cooking classes available for anyone living in BC who is interested, visit: https://bit.ly/BWPnutritionclasses

Anything else you would like to add?

Everyone’s journey is different, and their health and nutrition priorities can be very different too. I acknowledge that sometimes working with a dietitian alone cannot address the nutrition problem. Some people may need reminders to eat, others may have trouble chewing or swallowing, and some people may need extra support, time, or strength to prepare the meal. Many healthcare workers, including people at the Brain Wellness Program, hope to form a network and community that delivers person-centred, team-based care to work better together with people living with PD and caregivers.

I also want to acknowledge that food is not just about nutrition. It can be what brings people together, childhood memories, the treat of the day, and language of care. I hope this can be a reminder for whoever is reading this article to continue to connect, talk, share, and create memories over food!

Additional Resources and Further Reading

Older Adult Nutrition Screening – Resources for Older Adults | https://bit.ly/4ebhSAY 

Rusch, C., Flanagan, R., Suh, H., & Subramanian, I. (2023). To restrict or not to restrict? Practical considerations for optimizing dietary protein interactions on levodopa absorption in Parkinson's disease. NPJ Parkinson's Disease, 9(1), 98. https://doi.org/10.1038/s41531-023-00541-w 

This content was published in the Winter 2024 edition of our quarterly magazine, Viewpoints. The content was accurate as of this publication date.