Could a healthy diet keep Parkinson’s at bay?
Triggers for the neurological condition may be hidden in the gut, says Professor David Dexter
Can changing your diet cut your chances of developing Parkinson’s? Research from Harvard seems to suggest so. The findings, published in the journal Neurology, claim that eating a healthy, Mediterraneanstyle diet – high in fruit, veg, whole grains, nuts and legumes and low in red meat – can affect early symptoms associated with an increased risk of developing the disease.
For the study, every four years more than 47,000 people were asked about their diet, starting in the 1980s when they were middle-aged. It is part of wider research into the connections between diet and this progressive neurological condition, for which there is still no cure.
Parkinson’s develops when nerve cells in the brain stop working properly and are lost over time. Some brain cells produce a chemical called dopamine, which allows messages to be sent to the parts of the brain that coordinate movement. Without enough dopamine-producing cells, messages cannot get through and mild physical symptoms of Parkinson’s, such as tremor (shaking), slowness of movement and rigidity (muscle stiffness), appear.
But the loss of other cells using different chemical trigger symptoms, such as constipation, depression and sleep problems, can occur before these movement problems. Parkinson’s has more than 40 symptoms, each of which can affect people differently.
About 145,000 people live with Parkinson’s in the UK, but more than one million people are affected – either by living with the condition or as a friend, colleague or family member of someone who is. So finding anything that can help control the effects is crucial.
There are a variety of pharmaceutical treatments that can increase the amount of dopamine in the brain, act as a dopamine substitute and stimulate the parts of the brain where it operates, or block the action of other factors (enzymes) that break it down. But not all these drugs suit everyone, and many may work only for a while. Some can have severe side-effects, such as compulsive behaviour. The most well-known, levodopa, increases the amount of dopamine in the brain – but needs to be given in increasing doses as dopamine-producing brain cells are lost.
That’s why looking at lifestyle interventions, such as diet, is important – and this research is very interesting. What it shows is that eating a diet full of antioxidants and foods that are known to have an antiinflammatory effect and are found in a Mediterranean-style diet can decrease the risk of developing early symptoms.
In 2012, the participants were asked whether they had two conditions common in people later diagnosed with Parkinson’s disease: constipation and REM (rapid eye movement) sleep behaviour disorder, which includes physically acting out dreams during sleep.
Around two years later, 17,400 of the participants were asked about five more symptoms that can precede the disease: loss of sense of smell, impaired colour vision, excessive daytime sleepiness, body pain and depression.
The more closely participants kept to a Mediterranean-style diet, the less likely they were to show the early symptoms of sleep disturbances, constipation, loss of sense of smell and excessive daytime fatigue.
Those in the highest group for adherence were 33 per cent less likely to have three or more preceding symptoms than those in the lowest group, after researchers adjusted for factors such as physical activity, smoking and BMI.
With Parkinson’s, cell loss follows a pattern: it begins in the lower brainstem – which is why sensory and gut symptoms show up first, as this is where the relevant neurological connections occur – before moving higher up the brain structure.
So does the Mediterranean diet simply protect the brain cells directly, or is there an effect via the gut? We’re not sure yet. But research – some funded by Parkinson’s UK
– has shown us some parts of the picture: we know that Parkinson’s is associated with gut bacteria that can trigger inflammation, and that these bad bacteria are inhibited by food found in a Mediterranean-style diet. We’re funding clinical trials that will tell us whether getting rid of bad bacteria in the gut will slow the progression of the condition in people with diagnosed Parkinson’s.
A Mediterranean diet with emphasis on fibrous vegetables such as onions and asparagus can foster the right kind of gut bacteria. You can also supplement your diet with naturally occurring antioxidants and anti-inflammatory agents. Flavonoids, found in foods such as turmeric, which I take myself every day, are a good example.
You also need to ditch the sugary, high-fat foods – just as you would to lower your risk of heart disease. Too much sugar can cause type 2 diabetes – another risk factor for Parkinson’s.
In addition, the high cholesterol that furs up the arteries in your chest, is doing the same thing in your brain and restricting oxygen supply. A good rule of thumb is that if something in your diet is not heart-healthy, it is not good for your brain either.
The next question is when to change your diet to decrease the risk of Parkinson’s. This is tricky. If you show symptoms – such as a tremor
– in your sixties, the processes that cause the condition may have been triggered 10 to 15 years earlier. So to steal a march on the condition altogether, changes to your diet should be made from your thirties.
But that doesn’t mean it’s too late to improve your diet if you’re older, or even once you have the condition. Reducing inflammation and protecting the brain with antioxidants could potentially slow progression, but it will be a while before results from clinical trials confirm this.
While much of Parkinson’s is still a puzzle, and your genes also count, following a healthy diet as early as you can is a good place to start.
If a food isn’t hearthealthy, it’s not good for your brain, either