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

But beyond these general principles, many of you are curious about various claims that you have heard about particular foods or supplements to avoid for PD, particular foods or supplements to take for PD and specific diets to follow. There are many assertions out there about what is good or not good for PD, and it is hard to know what to believe or whether to change your diet based on these reports.

In this series of blogs, I am delving into some of these topics and analyzing what we know and what we don’t know as it relates to nutrition and PD. (As always, please consult your health care team to find out what is best for your particular situation.)

I divided my coverage of nutrition for Parkinson’s into three main topics to make it easier to digest (pun intended!):

• Part One: What we know and don’t know about avoiding particular foods/supplements.
• Part Two: What we know and don’t know about taking particular foods/supplements.
• Part Three: What we know and don’t know about adhering to particular diets.

Part One: What we know (and don’t know) about avoiding particular foods and supplements

Alcohol

Because people with PD may have an unsteady gait and balance impairment, they need to be more thoughtful about their alcohol intake than the general population. People should take a common-sense approach of limiting alcohol in mild PD, and being extra cautious if there are balance issues from PD. Social drinking for people with mild PD and no balance or gait issues is considered to be fine.

Protein

Some people with PD experience what is referred to as the “protein effect” in which dietary protein can interfere with absorption of levodopa. Protein and levodopa use the same transporter to cross the small intestine wall.  Therefore it’s possible that dietary protein can interfere with absorption of levodopa including beef, chicken, pork, fish and eggs.

The protein effect is suspected when a person has an unpredictable response to levodopa doses – some doses may work well while others do not. There are many potential causes for this problem and you can review a comprehensive discussion of this issue by viewing this APDA Webinar, Enhancing Communication About Off. To determine if the protein effect is responsible for an erratic response to medication, you will likely need to do some trial and error experimentation, for example, by withholding dietary protein until the end of the day to determine if medication responses are more reliable.

If protein does not appear to interfere in levodopa absorption, then there is no need to adjust or change your protein intake. If however, you discover that protein does in fact interfere with your levodopa absorption, there are two ways to adjust your diet in response:

• Ingest your daily protein at the end of the day, so that you do not have the protein effect during your active time
• Divide your protein evenly throughout the day – that way your medication absorption should theoretically be similar throughout the day. The APDA Living Well Every Day webinar includes a discussion of the protein effect and how to estimate the protein content of different foods, thereby helping you to design a diet with consistent amounts of protein throughout the day

Of course, if you are not currently taking levodopa, then you can carry on with your normal intake of protein.

Iron

Iron supplements can bind with levodopa and thereby reduce the amount of medication that is absorbed in your system. If you require iron supplementation because of another medical condition, discuss this with your doctor so you can determine how to most effectively get the iron you need while not impacting your PD medications.

Tyramine

Patients who are taking medications for PD that are classified as monoamine oxidase (MAO)-B inhibitors (rasagiline, selegiline, and safinamide) are often concerned about having to adhere to a particular diet which is low in the amino acid tyramine. This is because patients who are taking non-selective MAO inhibitors (that inhibit both MAO-A and MAO-B) for reasons other than PD, such as depression, do have to be concerned about adhering to that diet (which can be difficult, as many foods contain tyramine). When MAO-A is inhibited, the body can no longer break down tyramine effectively. Elevated levels of tyramine can then cause spikes in blood pressure and other negative effects. To be clear, there are no medications indicated for PD that inhibit MAO-A. However, at high doses, MAO-B inhibitors can begin to inhibit MAO-A as well. When MAO-B inhibitors are taken at the recommended doses for PD, tyramine is broken down effectively and dangerous levels are not reached.

Because of this, a diet low in tyramine is not required for those taking MAO-B inhibitors at the recommended doses for PD. For example, the package insert for rasagiline (Azilect) reads:

Dietary tyramine restriction is not required during treatment with recommended doses of Azilect.

There is a caveat to this statement however which reads:

However, certain foods that may contain very high amounts (i.e., more than 150 mg) of tyramine that could potentially cause severe hypertension because of tyramine interaction (including various clinical syndromes referred to as hypertensive urgency, crisis, or emergency) in patients taking Azilect, even at the recommended doses, due to increased sensitivity to tyramine.

It’s important to note that 150 mg of tyramine is a lot and most foods that contain tyramine do not contain this high of an amount. Some foods however, if eaten in large enough quantities may reach these levels, and these include aged cheeses, cured meats, and beer on tap. Avoiding these foods is reasonable for someone on an MAO-B inhibitor.

Vitamin B6 and B12

Vitamin B6 interacts with both carbidopa and levodopa. Current understanding is that Vitamin B6 drives the conversion of levodopa to dopamine and carbidopa irreversibly binds Vitamin B6. For most people, eating a healthy diet and taking standard doses of oral carbidopa/levodopa will result in an appropriate balance between these compounds, normal levels of Vitamin B6 in the system, and good PD symptom control. 

However, if nutrition is poor or if a person takes high doses of oral carbidopa/levodopa, Vitamin B6 levels could be too low. Of note, those on carbidopa/levodopa intestinal gel or Duopa may be more at risk for Vitamin B6 deficiency than those on oral carbidopa/levodopa. Signs of Vitamin B6 deficiency can include anemia, depression, confusion, and even seizures. Vitamin B6 can also cause peripheral neuropathy which can result in numbness, tingling, and pain in the feet as well as balance issues. If there is any concern, Vitamin B6 levels in the blood can be checked and supplementation can be given.

Rarely an excess of Vitamin B6 in the system (by taking too much of a Vitamin B6 supplement for example) might drive too much levodopa conversion to dopamine in the periphery before it gets to the brain leading to poorer PD symptom control. Practically, this is only a concern if a person is taking levodopa without carbidopa. Overall, Vitamin B6 deficiency is more of a potential issue than Vitamin B6 excess.

Vitamin B12 is another key vitamin that shares metabolic pathways with Vitamin B6. Vitamin B12 deficiency is common in the aging population in general and may be even more common in people with PD. Vitamin B12 deficiency can cause a whole host of symptoms including fatigue, signs of peripheral neuropathy (numbness, tingling, pain, balance issues), memory problems, depression, and irritability. This article highlights the relationship between Vitamin B6, Vitamin B12, and Parkinson’s disease.

The bottom line is – talk with your neurologist about possibly checking your Vitamin B6 and Vitamin B12 levels. If they are low, talk with your doctor about how to take the appropriate supplementation. 

Dairy

Population studies have shown a slightly elevated risk of PD in people who report high consumption of dairy, as compared to people who report low consumption of dairy. The reason for the association between increased risk of PD and dairy is not known. It is important to note that these studies do not address the effects of dairy on people who already have PD.

These studies demonstrate an association (meaning a small elevated risk of PD and dairy coexists) – but not a causation (that consuming dairy causes the elevated risk.) There may be an innocuous link between dairy and PD that explains the connection (e.g. just for argument’s sake – no data exists to suggest this – people who carry a genetic predisposition to PD also carry a genetic predisposition to enjoying dairy.) but that has yet to be discovered.

Two theories that have been suggested but not proven to explain the connection are that 1) dairy may contain a pesticide that contributes to PD risk or that 2) dairy may lower uric acid in the body, a substance which may be protective of PD.

On the other side of the argument is the fact that dairy serves as an excellent source of calcium, vitamin D and other essential nutrients. Calcium and vitamin D are vital to support bone strength which is necessary to decrease the probability of fractures in people with PD who may be prone to falls. Vitamin D deficiency specifically has also been linked to PD, so all things considered, it may be detrimental to people with PD to eliminate a dietary source of calcium and vitamin D.

The bottom line is that there is currently not enough information to make a particular dietary recommendation concerning dairy for people with PD.

Stay tuned next week for a discussion about what we know (and don’t know) about taking particular foods/supplements that are often talked about for people with PD.

Tips and Takeaways

• It is hard to sift through all the information on the internet about foods and supplements to avoid in people with PD. There are a lot of claims about nutrition and PD out there so it is important to consult credible sources.
• There are foods and supplements that are best avoided by people taking levodopa in order to maximize medication absorption.
• People taking monoamine oxidase-B inhibitors for PD such as rasagiline, selegiline and safinamide, do not have to adhere to a specific diet, but should avoid foods that are very high in tyramine such as aged cheeses, cured meats and beer on tap.
• Diets high in dairy have been associated with a slightly increased risk of PD. However, dairy products also have health benefits. All things considered, there is not enough information to recommend eliminating dairy products for people with PD.
• Discuss nutrition questions and concerns with your health care team to determine what choices are best for your personal situation.