A healthy diet may help ease early Parkinson’s symptoms, research suggests.
Although typically associated with tremors, many patients endure constipation, fatigue and depression up to a decade before their movement is affected.
After analysing more than 47,000 people over three decades, scientists from Harvard found eating a diet rich in fruit, vegetables and whole grains in middle age may cut the onset of early symptoms by a third (33%).
“While this study does not show cause and effect, it certainly provides yet another reason for getting more vegetables, nuts and legumes in your diet,” said study author Dr Samantha Molsberry.
“More research is needed to determine whether eating a healthy diet could delay or even prevent the development of Parkinson’s disease among people who have these preceding symptoms already.”
More than 145,000 people over 20 in the UK are thought to have been living with Parkinson’s in 2018. In the US, nearly 1 million people have the disease.
Parkinson’s comes about when nerve cells that produce the chemical messenger dopamine, which regulates movement, die off.
Patients typically develop tremors, slow movement and loss of balance when 80% of dopamine is lost.
In the early stages of the disease, they may notice a reduced sense of smell, insomnia or dizziness.
With no cure, treatments aim to ease symptoms and improve a patient’s quality of life.
To better understand how early symptoms could be relieved, the Harvard scientists asked more than 47,000 middle-aged people about their diet every four years, starting in the 1980s.
In 2012, the same participants were asked whether they had two conditions that are common among those who go on to be diagnosed with Parkinson’s – constipation and rapid eye movement sleep behaviour disorder.
The latter can cause patients to act out dreams by flailing their arms or shouting.
Between 2014 and 2015, 17,400 of the participants were asked about five more symptoms that can precede Parkinson’s: loss of smell, impaired colour vision, excessive daytime sleepiness, pain and depression.
The scientists looked at how closely the participants’ eating habits followed either the alternate Mediterranean diet or the Alternative Healthy Eating Index (AHEI), which is based on foods that are known to ward off chronic disease.
The alternate Mediterranean diet is similar to the much-praised eating plan but excludes dairy and any processed grains.
Both diets are rich in fruit, vegetables, whole grains, nuts and legumes, while discouraging red meat.
The participants were divided into five groups based on how closely they adhered to the eating habits.
Results – published in the journal Neurology – revealed those who most closely followed the alternate Mediterranean diet were 33% less likely to have three or more early Parkinson’s symptoms than those in the lowest adherence group, with similar findings also occurring for those on the AHEI.
This remained true after the scientists adjusted for other factors that can affect symptom risk, like physical activity, smoking and weight.
The scientists concluded eating more vegetables, nuts and legumes, while drinking moderately, was associated with a lower risk of developing three or more early Parkinson’s symptoms.
Moderate alcohol consumption was defined as no more than one drink a day for women and a maximum of two a day for men.
“We need to emphasise that, while these symptoms are associated with an increased risk of Parkinson’s disease, especially in combination, experiencing any or several of these symptoms does not necessarily mean that a person will eventually develop Parkinson’s disease,” said Dr Molsberry.
Constipation is often a result of insufficient water or fibre in a person’s diet, as well as sometimes being a side effect of certain drugs.
Fatigue is also relatively common, with many people suffering sleepless nights for a variety of reasons.
The scientists also pointed out the participants were not asked about any preceding symptoms at the start of the study. Some may have therefore already changed their diet as a result of these warning signs.