What is the link between blood sugar and Parkinson's disease?
- Melody Mackeown
- 1 day ago
- 6 min read
A nutritional therapist explores how blood sugar, insulin, and metabolism may influence symptoms, brain health, and daily life with Parkinson’s disease.
In this article we will look at:
Parkinson’s disease is often described as a movement disorder, but it is much more than that. Many people living with Parkinson’s also experience fatigue, brain fog, reduced thinking speed, sleep problems, and mood changes. Increasingly, researchers are looking at whether some of these symptoms may be linked to metabolism, particularly how the body and brain handle glucose, or blood sugar.
This is a fascinating area because the brain is highly dependent on energy. It needs a steady supply of fuel to support movement, thinking, mood, and communication between brain cells. When blood sugar is unstable, or when brain cells struggle to use glucose efficiently, that may add to the burden already placed on the nervous system in Parkinson’s.
How does the brain use glucose?
The brain uses around 20% of the body’s daily glucose despite its relatively small size. It cannot store much energy, so it depends on a constant supply from the bloodstream.
That means the quality of the fuel matters as much as the amount. If blood sugar rises and falls sharply after meals, the body has to work harder to keep things balanced. Over time, repeated spikes and crashes can contribute to insulin resistance and make it harder for cells to use glucose properly.
In Parkinson’s disease, researchers have found signs of impaired glucose metabolism in the brain [1]. This suggests that neurons may not be using fuel as efficiently as they should. If that happens, brain cells may become more vulnerable to stress and less able to perform their usual roles.
What is the role of insulin in Parkinson’s disease?
Insulin is usually thought of as a hormone that helps regulate blood sugar, but it also has important jobs in the brain. It supports energy use, cell survival, and communication between neurons [2].
When insulin signalling is disrupted, brain cells may struggle to use glucose effectively. In Parkinson’s disease, this has led researchers to explore whether insulin resistance in the brain could be part of the disease process [3].
This does not mean Parkinson’s is simply “diabetes of the brain.” But it suggests that the same metabolic pathways involved in blood sugar control may also influence brain function. Research has linked impaired insulin signalling in Parkinson’s to:
Increased oxidative stress
Higher levels of inflammation
Mitochondrial dysfunction, which affects energy production
Greater vulnerability of dopamine-producing neurons
Problems with protein handling inside cells
These are important because dopamine-producing neurons are the cells most affected in Parkinson’s disease. If their energy supply is compromised, they may be less able to cope with everyday stressors.
How do blood sugar swings affect Parkinson’s symptoms?
When blood sugar rises quickly after a meal and then drops again, it can create a rollercoaster effect. For some people, this may show up as low energy, poor concentration, irritability, or a “foggy” feeling.
For people living with Parkinson’s, this may be especially relevant. The brain is already under metabolic strain, so unstable blood sugar may influence how symptoms such as fatigue or mental slowing are experienced.
Researchers are now paying closer attention to this relationship. In studies of Parkinson’s disease, glucose dysregulation has been linked with disease progression and altered brain metabolism [4]. That makes blood sugar an interesting area not only for general health but also for neurological resilience.
The gut, blood sugar, and Parkinson’s disease
Another reason this topic matters is the growing evidence around the gut-brain axis, which we explored in our earlier article Rethinking Parkinson’s disease: nutrition, lifestyle and the gut-brain connection.
Parkinson’s disease is increasingly understood as a condition that affects the body in multiple ways, not just the brain. Many people experience gut symptoms long before motor symptoms appear, and changes in the gut microbiome are now thought to play a role in disease development and progression.
This matters because diet influences both blood sugar and the gut microbiome. A dietary pattern that supports steady glucose levels may also help create a healthier gut environment. That could be important in Parkinson’s, where gut health, inflammation, and brain function are closely connected.
What is the best diet for blood sugar and brain health?
The good news is that the same eating habits that help balance blood sugar can also support brain health more broadly.
A more Mediterranean-style pattern is often a helpful starting point. This includes:
Plenty of vegetables and fruit
Beans, lentils and other legumes
Whole grains instead of refined carbohydrates
Nuts, seeds, and healthy fats such as olive oil
Fish and other good-quality protein sources
Fewer ultra-processed foods and sugary drinks
These foods are rich in fibre, magnesium, omega-3 fats, and B vitamins, all nutrients that support energy metabolism, nervous system function, and overall brain health.
They also help slow the release of glucose into the bloodstream, which may reduce the spikes and crashes that can leave people feeling tired or mentally flat.
Practical steps to support blood sugar in Parkinson’s disease
You do not need a perfect diet to make a difference. Small, consistent changes are often more realistic and more effective.
A few practical steps include:
Pair carbohydrates with protein, fat, and fibre
Choose minimally processed foods whenever possible
Limit sugary drinks and frequent sweet snacks
Try a short walk after meals to help glucose regulation
Keep mealtimes fairly regular
Support sleep and stress management, which both affect blood sugar control
These habits will not replace medical care, but they may play a supporting role.
A broader view of blood sugar and Parkinson’s disease
Parkinson’s disease is complex, and there is no single dietary solution. But the evidence is growing that metabolism matters, and that blood sugar balance may be one part of the picture.
For people living with Parkinson’s, paying attention to stable energy, nutrient intake, and gut health may be a helpful way to support both brain and body. It is not about chasing perfection or making drastic changes. It is about creating a more stable internal environment, one meal and one habit at a time.
That may not sound dramatic, but in a condition like Parkinson’s, small daily choices can add up.
Key takeaways
Parkinson’s disease is no longer understood as a condition that affects only the brain. Growing research is highlighting the role of metabolism, particularly how the body and brain handle glucose, in supporting overall neurological resilience.
For people living with Parkinson’s, or those concerned about their risk, stable blood sugar may be one piece of a much larger puzzle. Diet, gut health, and lifestyle all influence how efficiently the brain uses energy, and small, consistent habits often have a greater impact than dramatic changes.
What the evidence increasingly suggests is that nutrition is not a side note in Parkinson’s care, but a foundational area worth focusing on. Pairing carbohydrates wisely, eating minimally processed foods, and supporting the gut may all help create a steadier internal environment, one meal and one habit at a time.
Work with Melody
Melody Mackeown is a Nutritional Therapist specialising in Parkinson’s disease and digestive health. She holds a BSc in Psychology, an MSc in Personalised Nutrition, and a Dip ION from the Institute for Optimum Nutrition, London. She is registered with BANT and CNHC, and supports individuals living with symptoms of Parkinsonism, an existing diagnosis, or those concerned about their risk.
Melody works through the lens of personalised nutrition, drawing on functional testing where appropriate to build a tailored plan around each individual’s unique biochemistry, symptoms and goals.
"If you'd like to find out more about working with me, visit my profile."
References
Sian-Hulsmann J, Riederer P, Michel TM. Metabolic Dysfunction in Parkinson's Disease: Unraveling the Glucose-Lipid Connection. Biomedicines. 2024;12(12):2841. PMID: 39767747.
Mason AC, Fatih N, Sofat R, Rentsch CT, Smeeth L, Bhaskaran K, Chaturvedi N, Garfield V. Disentangling the relationship between glucose, insulin and brain health: a UK Biobank study. Diabetes, Obesity and Metabolism. 2025. PMID: 40387205.
Athauda D, Foltynie T. Insulin resistance and Parkinson's disease: A new target for disease modification? Progress in Neurobiology. 2016;145-146:98-120. PMID: 27713036.
Chen L, Wang C, Qin L, Zhang H. Parkinson's disease and glucose metabolism impairment. Translational Neurodegeneration. 2025;14(1):10. PMID: 39962629.
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