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Cognitive health: Parkinson’s disease

Cognitive health: Parkinson’s disease

The first thing you may think of when you hear the words Parkinson’s disease is someone with shaky hands. However while its main symptoms affect the body, Parkinson’s is a long-term degenerative disease caused by a problem in the brain.

Named after the English doctor James Parkinson in the early 19th century, Parkinson’s is the fastest growing neurological condition in the world, and around 145,000 people are estimated to be living with it in the UK (i).

The National Institute of Health and Care Excellence (NICE) says Parkinson’s is a common condition in elderly people, with more than 17,000 new cases diagnosed in people aged 45 and older every year (ii). If you’re aged 50 - 69, your chances of developing it double every five years. Men aged 50 - 89 are also more than 1.5 times more likely to be affected by Parkinson’s than women (this, NICE explains, is the equivalent of 22 in every 10,000 women and 32 in every 10,000 men).

Or to put it more plainly, one in every 37 people is diagnosed with Parkinson’s at some point in their lifetime. And even if you don’t know a friend or family member who’s affected by it, you’ve probably heard of the boxer Muhammad Ali and the actors Michael J Fox and Alan Alda, all of whom have or have had Parkinson’s.

Most people with Parkinson’s develop symptoms in their 50s or older, but around one in 20 people with the condition first experiences symptoms before the age of 40. In other words, while Parkinson’s is largely seen as a condition that affects people when they’re older, it can sometimes affect younger people too.

What are the symptoms of Parkinson’s disease?

There are three main symptoms of Parkinson’s, all of which affect body movement:

  • Shaking (tremor) is arguably the best-known symptom, but while it’s one of the three main symptoms it doesn’t affect everyone who has Parkinson’s. Typically this shakiness is seen in the fingers, thumbs, hands and arms, but it can affect other body parts too. You may find it gets worse when you’re emotional, excited, tired or anxious. The shaking can subside when you’re using your hands (or whatever part of your body is affected). It can be more obvious, however, when you’re resting.

  • Slow movement – or bradykinesia – can make everyday tasks harder because you take longer than usual to do even simple things. Again not everyone with Parkinson’s is affected. For instance you may walk slowly with short, shuffling steps, you may take longer than usual to get up from your chair or you may have difficulties with co-ordination – all of these can, however, be mistaken for general signs of getting older.

  • Muscle stiffness (or rigidity) is when your muscles feel tense and inflexible. For instance, you could find it difficult to turn over in bed or to get up out of a chair. It can also cause problems with handwriting (which tends to become smaller), tying your shoe laces or doing up buttons, and you may not be able to swing your arms very much when you walk. If the muscles in your face are stiff you may find it difficult to make facial expressions or blink as often as normal. You could also experience muscle pain and cramps (dystonia).


There can be other causes of all of these main symptoms, which together are often referred to as parkinsonism. Besides Parkinson’s itself, these other conditions include:

  • Vascular parkinsonism, or arteriosclerotic parkinsonism, is found in people who have had a restricted blood flow to the brain – during a mild stroke, for example.

  • Drug-induced parkinsonism is caused by certain medicines, including neuroleptic drugs used to treat psychotic disorders. Once you stop taking the drug that’s causing the symptoms, the symptoms stop.

  • Other conditions that cause parkinsonism include multiple system atrophy, progressive supranuclear palsy, normal pressure hydrocephalus and rarer conditions such as Wilson’s disease.

What are the other symptoms and complications?

Besides the three main symptoms of Parkinson’s there are many other physical symptoms, including:

  • Problems with swallowing (dysphagia)

  • Speech difficulties (where speech becomes slow and monotonous)

  • Greater risk of falling (as a result of problems with balance and posture)

  • Freezing (where you suddenly feel you can’t move, like your feet are stuck to the ground)

  • Loss of sense of smell (this is often an early symptom that can start years before other symptoms develop)

  • Nerve pain

  • Frequent urination

  • Constipation

  • Sexual dysfunction

  • Excessive sweating

  • Sleep difficulties, which can lead to tiredness, fatigue and daytime sleepiness

  • Dizziness, fainting and blurred vision (usually caused by a sudden drop in blood pressure when you stand up from sitting or lying, for instance)

  • Producing too much saliva (drooling)

Some people with Parkinson’s also experience cognitive and mental health problems such as depression, anxiety, mild cognitive impairment and dementia (around half of people with Parkinson’s develop dementia at some stage (iii)). The condition is linked with compulsive behaviours too, such as compulsive eating, shopping, sex or gambling – though this is thought to be a result of taking some types of medication used to treat Parkinson’s (see dopamine agonists, below).

Meanwhile there’s evidence that people with Parkinson’s are more likely than normal to develop melanoma skin cancer, which means they should take extra care to protect their skin when out in the sun (iii).

What causes Parkinson’s disease?

Experts know what happens in the brain to cause Parkinson’s disease symptoms. What they don’t know, however, is why it happens, and why some people develop these changes in the brain while others do not.

The part of the brain affected is called the substantia nigra. Technically speaking this is a basal ganglia structure, and it’s found in the part of the brain called the midbrain. One of the main functions of the substantia nigra is to send messages to parts of the brain that co-ordinate movement. These messages are transmitted by chemicals called neurotransmitters, the main one being a chemical called dopamine.

If you have Parkinson’s, cells in the substantia nigra in your brain become damaged and die. And because Parkinson’s is a progressive condition, more and more of these cells become damaged and die over time. All of this means the substantia nigra produces less and less dopamine. Combine this with the fact that there are fewer cells in the substantia nigra, and the result is that messages from the brain to the muscles become slower and abnormal, which causes the range of symptoms seen in Parkinson’s.

But why are these particular brain cells affected in people with Parkinson’s? The truth is we don’t really know, though according to Parkinson’s UK researchers believe it’s a combination of age, genetic changes and environmental factors that cause the cells in the substantia nigra to die (iv).

  • Parkinson’s can run in families, but it’s very rare, and only a very small number of people have an increased risk of developing it because of their genes. So if you have Parkinson’s it’s highly unlikely you’ll pass it to your children. Similarly your chances of developing it if one of your parents has or had Parkinson’s are slim.

  • Environmental factors are toxins that may cause cells in the substantia nigra to die, and according to Parkinson’s UK there is some evidence this can happen (iv). There have, for instance, been theories that using herbicides and pesticides can lead to the development of Parkinson’s. However, according to the NHS, the evidence linking environmental factors to Parkinson’s disease is inconclusive (v).

What are the treatments for Parkinson's disease?

The good news is that, while we still don’t have a cure for Parkinson’s, we do have treatments that can help relieve the symptoms. This means someone with Parkinson’s today can have a good quality of life. And while admittedly the symptoms usually get worse over time – which can mean those affected could eventually need help with everyday activities – most people with Parkinson’s disease have a normal or near-normal life expectancy, thanks to the way treatments have advanced (vi).

If you’re diagnosed with Parkinson’s early on you may not need any treatment until your symptoms progress. Usually, this will include one or more medicines such as:

Levodopa: This is the most widely used medication for Parkinson’s and most people who are affected by the disease will eventually take it. Levodopa is converted in the brain to dopamine, and the vast majority of people with Parkinson’s find it improves their symptoms (iii). Over time, however, levodopa tends to work less effectively, which means the dosage is often increased every now and then. However this can cause problems in some people who take levodopa in the long term, including so-called ‘on-off’ effects (where you switch suddenly from being able to move and not being able to move) and uncontrollable jerky movements.

If you take levodopa, you may also need to take other medications to help it get to the brain where it’s needed, instead of being converted into dopamine in the bloodstream.

Dopamine agonists: Acting on the same receptors in the brain as dopamine, these have similar, but milder, effects compared with levodopa, and are often taken alongside levodopa (in which case a lower dose of levodopa can often be used). These medicines, however, have been linked to the development of compulsive behaviours.

Monoamine oxidase-B inhibitors: These medicines are sometimes used to treat people with early Parkinson’s disease. They work by blocking a chemical in the brain called MAO-B, which is involved in breaking down dopamine. This means any dopamine you produce will last longer.

Catechol-O-methyltransferase inhibitors: Typically prescribed for those who are in the later stages of Parkinson’s, these medicines stop levodopa being broken down by an enzyme called catechol-O-methyltransferase (COMT), so that more of each dose can get into the brain.

Surgery is also an option for some people. This type of surgery is called deep brain stimulation, which involves implanting a pulse generator into the chest that’s connected via one or two fine wires to the brain. Small electrical pulses then stimulate the part of the brain affected by the condition. It’s not suitable for everyone with Parkinson’s, but it can ease the symptoms in some people. Find out more about deep brain stimulation for Parkinson’s disease here

Meanwhile there are several therapies that can help people with Parkinson’s live as independently as possible and maintain their quality of life as their condition progresses. These include physiotherapy (to relieve muscle stiffness and joint pain), occupational therapy (to offer practical solutions to everyday problems) and speech and language therapy.

Diet and exercise for Parkinson’s

Besides medical and therapeutical treatments there are a few things you can do yourself to help manage your Parkinson’s symptoms – including making changes to your diet and taking regular exercise.

There’s no specific diet you should follow – just try to eat as balanced and healthy a diet as possible, making sure you get at least five portions of fruit and vegetables every day. This can help support your health in general and keep your weight within the normal range. Eating a good amount of fibre and drinking plenty of fluids can also help if you’re experiencing constipation, which often affects people with Parkinson’s. Increasing the amount of salt in your diet and eating smaller, more frequent meals may even help if you’re experiencing dizziness and feeling faint (vii).

However if you’re considering taking any nutritional supplements, check with your doctor or specialist first, since some – vitamin B6 and iron supplements, for example – can affect the absorption of some Parkinson’s medication (viii). Meanwhile, according to Parkinson’s UK experts suggest people with the condition should be taking a calcium and vitamin D supplement, especially those who aren’t getting enough vitamin D because they’re house-bound or immobile. This is because Parkinson’s symptoms have been linked with reduced bone density, which can make bones weaker and more likely to break (viii).

Exercising, on the other hand, may be the last thing you feel like doing if you have Parkinson’s. But according to Parkinson’s UK, doing two and a half hours of exercise a week may slow the progression of your symptoms. Meanwhile staying active could help you manage physical symptoms as well as others such as fatigue, mood and sleep problems (ix).

There’s no ideal exercise for everyone with Parkinson’s – just do whatever helps you feel and stay as fit as possible. However here’s what the experts at Parkinson’s UK advise, depending on the severity and stage of your symptoms:

  • If your symptoms are mild, focus on vigorous exercise such as running, cycling and circuit training (x)

  • If your symptoms are progressing, focus on exercise that takes effort and pushes you (xi)

  • If your symptoms are more complex, concentrate on everyday movements and activities you find difficult – getting up from a chair, for example (also try chair-based exercises) (xii)

Natural supplements for brain support

Few nutritional or herbal supplements are recommended for those with Parkinson’s (see above) or for its prevention. Some may even interfere with the absorption of some Parkinson’s medicines. For instance, St John’s wort, which has been used traditionally to relieve low mood, isn’t recommended for people with Parkinson’s at all because it can interact with some Parkinson’s medicines (xiii).

That said, there are several natural products that may help support general brain health – though if you have Parkinson’s and you’re considering taking any of them, it’s essential to check with your doctor or specialist beforehand.

Here are a few brain health supplements – read more about them and the scientific evidence that supports their use for cognition support in our guide to nutrition for the brain.

High-strength fish oils: Supplements made from oily fish that contain the omega-3 fatty acids EPA and DHA are thought to be good for your brain, so they may be particularly beneficial if you don’t like eating fish. One study has even suggested a protein in fish – called beta-parvalbumin – may help prevent Parkinson’s (xiv). If you’re a vegetarian or vegan you can now get these important omega-3s in a veggie/vegan-friendly formulation – look for omega-3 supplements that contain algae, which supply fish with omega-3s in the first place.

Turmeric (curcumin): Curcumin is one of the many active ingredients found in the curry spice turmeric, and may be helpful for cognitive decline. There is in fact some evidence that curcumin could help prevent the formation of a protein called α-synuclein, which may contribute to the loss of cells in the substantia nigra – though the research was carried out in a lab, which means it’s not as robust as a human trial (xv). You can add turmeric to your food, or take a turmeric supplement if that’s more convenient. Consider trying a good-quality supplement that provides a high percentage of curcuminoids (curcumin is a type of curcuminoid).

Ginkgo biloba: Nutritional therapists often use the herb ginkgo biloba to treat cognitive function in older people. So far, however, studies have only investigated the use of ginkgo in animal models of Parkinson’s.

Astaxanthin: Antioxidants may be helpful in supporting cognitive health, especially if your levels are already less than decent. Like gingko, however, studies investigating the use of astaxanthin in Parkinson’s have so far been limited to animal trials. A particularly potent antioxidant found in a type of freshwater algae, astaxanthin can be found in supplement form as well as in foods such as salmon, lobster, crawfish, rainbow trout and crab. As a supplement it is usually suitable for vegetarians and vegans (check the label – some capsules can contain non-vegetarian and non-vegan ingredients).

Iodine: If you’re deficient in this essential mineral it can lead to an underactive thyroid, which can affect your cognition. There is also some evidence – though it’s weaker than that for thyroid issues – that iodine deficiency may also be implicated in Parkinson’s (xvi). You can get iodine in fish, eggs and other dairy products, as well as in nutritional supplements such as multivitamins.

Zinc: This essential nutrient is found in high levels in the brain. Some researchers have also suggested that if you have low zinc levels, your risk for Parkinson’s may be increased (xvii). You can get zinc in foods such as meat, nuts and dairy products, or if you don’t get much in your diet try a zinc supplement or multivitamin that has good zinc levels.

Vitamin C: Vitamin C is widely found in foods, yet some people may not be getting enough of it in their diets. Some scientists even believe it may help with cognitive functioning, plus there’s also some evidence that a diet rich in antioxidants such as vitamin C and vitamin E may lower the risk of developing Parkinson’s (xviii). You can get vitamin C supplements in many forms, including tablets, capsules and powder.

Magnesium: Found in foods such as dark chocolate, nuts, seeds, legumes, milk, oily fish, red meat and leafy green vegetables, magnesium may be beneficial if you want to give your brain a boost. However, despite the fact that it’s in many different foods, some people may have low levels of magnesium. If you want to try a supplement, look for magnesium in a more absorbable form, such as magnesium citrate.

Green tea: If you like drinking green tea, your brain may already be getting a supply of certain helpful compounds. A review of studies into green tea with a special focus on Parkinson’s disease even suggests green tea may protect against damage in the brain – but the researchers claim more research is needed to identify the amount of green tea you need to get the benefits (xix). If you’re not a fan of the taste of green tea you can try a supplement – choose a product with a good level of active antioxidant ingredients called polyphenols.

There’s lots more to discover about issues that affect the brain in the cognitive health section of our health library.


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Disclaimer: The information presented by Nature's Best is for informational purposes only. It is based on scientific studies (human, animal, or in vitro), clinical experience, or traditional usage as cited in each article. The results reported may not necessarily occur in all individuals. Self-treatment is not recommended for life-threatening conditions that require medical treatment under a doctor's care. For many of the conditions discussed, treatment with prescription or over the counter medication is also available. Consult your doctor, practitioner, and/or pharmacist for any health problem and before using any supplements or before making any changes in prescribed medications.

Our Author - Christine Morgan


Christine Morgan has been a freelance health and wellbeing journalist for almost 20 years, having written for numerous publications including the Daily Mirror, S Magazine, Top Sante, Healthy, Woman & Home, Zest, Allergy, Healthy Times and Pregnancy & Birth; she has also edited several titles such as Women’ Health, Shine’s Real Health & Beauty and All About Health.

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