Diets for Parkinson’s — research explained

Claire Bale
Oct 16, 2018 · 5 min read

If you have Parkinson’s, there is no specific diet you should follow. Getting the right nutrition is vital but it’s also individual and will depend on a range of factors including your weight, activity levels, any other health issues you have and the medications you take. So it’s really important to speak to your doctor or nurse before making any significant changes.

In this blog, we’re going to take a look at some of the diets we are most often asked about by people with Parkinson’s and what emerging research tells us about their potential benefits for people with the condition.


Mediterranean

Mediterranean diets are high in vegetables, fruits, legumes, nuts, beans, cereals, grains, fish, and unsaturated fats such as olive oil. They usually include a low intake of meat and dairy foods.

What does the research say?
A comprehensive study published in the British Medical Journal reviewed data from 12 separate studies (together involving over 1.5 million people) focused on Mediterranean diet, life expectancy, and incidence of chronic diseases.

This study found that following a Mediterranean diet is linked to improved health and reduced risk of cardiovascular diseases (like heart disease and stroke), cancer, Parkinson’s and Alzheimer’s. It also suggested that the more closely you follow a Mediterranean diet the stronger these protective effects.

Ketogenic

The ketogenic diet is a specialist medical diet that is much higher in fats and lower in carbohydrates than a typical diet. This forces the body to shift its usual energy source from glucose (sugar) to fats, or ketone bodies. It can be helpful for people with severe epilepsy but is now being investigated for other conditions.

What does the research say?
Studies conducted in cells and animal models suggest that a ketogenic diet may have protective effects on the brain, including on the dopamine-producing brain cells that are known to be damaged and lost in Parkinson’s. These protective effects may be due in part to improved health and function of the mitochondria — the energy-producing batteries that power cells.

Results from one very small pilot study in 7 people with the condition, showed that 5 were able to follow a ketogenic diet for 28 days and showed some improvement in symptoms. Unfortunately, there have so far been no large, long-term studies in people with Parkinson’s which means we don’t know whether this diet is practical, safe or effective in the long term.

Intermittent fasting

Intermittent fasting is an umbrella term for various diets that cycle between a period of fasting and non-fasting during a defined period — one of the most popular is called the 5:2 diet in which people eat normally five days a week, and significantly cut their calorie intake on the other two.

What does the research say?
Studies in rats and mice suggest that restricted calorie diets or intermittent fasting regimes help to protect brain cells from damage that is believed to be involved in conditions like Parkinson’s.

These diets trigger a range of biological changes in the body. One that may be at the root of this protection is a hormone called ghrelin — which is produced when the stomach is empty and known as the ‘hunger hormone’. Experiments suggest that ghrelin can protect brain cells in a dish from dying when they are exposed to chemicals that mimic the damage caused in Parkinson’s.

So far, there haven’t been any research studies looking at either calorie restriction or intermittent fasting in people so we don’t know how practical, safe or beneficial this type of diet may be for people with the condition.

Low or restricted protein

A low-protein diet involves eating less high protein foods including dairy products, eggs, beans, pulses, fish, and meat, and eating more low-protein food such as cereal products (e.g. bread, rice, and pasta), fruit, and vegetables.

What does the research say?
For some people with Parkinson’s, protein seems to interfere with how well levodopa is absorbed by the body and can cause fluctuations in symptoms. As a result, a large number of studies have investigated whether reducing protein intake or controlling when people eat protein in the day (protein redistribution) may be helpful for those people.

A recent review of all these studies found that low protein or redistributed protein diets can be beneficial for people with Parkinson’s who experience fluctuations in the effectiveness of their medication due to dietary protein. However, there can be side effects including increasing dyskinesia (uncontrolled movements) and weight loss which need to be carefully monitored.

Gluten-free

The gluten-free diet excludes the protein gluten, which is found in wheat, barley and rye. In people who have coeliac disease, gluten sensitivity or a gluten allergy, this protein can cause inflammation in the gastrointestinal tract (with accompanying abdominal bloating, nausea and diarrhoea).

What’s does the research say?
There is currently no evidence from research in either the lab or in people to suggest that a gluten-free diet has benefits for people with Parkinson’s.

The only relevant research report concerns a gentleman with Parkinson’s who had silent coeliac disease. People with this ‘silent’ form have an intolerance or allergy to gluten but do not experience the typical gastrointestinal problems and so often go undiagnosed. When this man went gluten free he experienced a significant improvement in his Parkinson’s symptoms — so it may be that others with silent coeliac disease could also benefit.


What have we missed?

We’ve tried to cover the main diets that we are asked about in relation to Parkinson’s, and that have at least some research evidence behind them, but if we’ve missed one then let us know in the comments below and we’ll add it if we can.


Want to read more?

You can read more about nutrition in Parkinson’s, and how researchers are using a new approach to investigate the influence of diet and lifestyle factors, in our previous blog about nutrition.

This blog is not meant as health advice. You should always consult a qualified health professional or specialist before making any changes to your medications or lifestyle.

Parkinson’s UK

Get the latest research news, discover more about Parkinson’s and read about how others are getting involved. For information and support, visit www.parkinsons.org.uk

Claire Bale

Written by

Head of Research Communications and Engagement, Parkinson’s UK

Parkinson’s UK

Get the latest research news, discover more about Parkinson’s and read about how others are getting involved. For information and support, visit www.parkinsons.org.uk

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