Prof. Dr. Bas Bloem (1967) is professor of neurological movement disorders at Radboud university medical center and is the world’s leading Parkinson’s expert. As an ambassador for ParkinsonNL, he is committed to raising awareness about Parkinson’s and the importance of scientific research. In 2022, Bas Bloem and his team received the NWO Stevin Prize for the social impact of the research he conducts into Parkinson’s disease.
Parkinson’s disease is the fastest growing neurological disorder today. More than 60,000 Dutch people now have Parkinson’s. Worldwide, a more than doubling is expected by 2040. “Although age is the biggest risk factor, it is a major misconception that only the elderly develop Parkinson’s disease. Young, old, man, woman: the disease spares no one,” says Bloem. “A third of people are younger than 65 when diagnosed. The peak of the disease is in people in their sixties and seventies. These are people who are in the middle of life. They have children and grandchildren, want to travel, want to enjoy themselves. That makes its impact so great.”
What exactly happens in the brain when you suffer from Parkinson’s?
“A lot of things, but the most important thing is that a dopamine deficiency occurs because a certain area in the brain – the substantia nigra – dies at an accelerated rate. You could see dopamine as the gasoline of the engine in the brain; when it is deficient, all kinds of brain functions are disrupted. One of the first, lesser-known symptoms of Parkinson’s is loss of smell. This occurs in 70 to 90 percent of patients. REM sleep disorders also occur at an early stage. These symptoms often exist years before the diagnosis of Parkinson’s is made.
Only when 60 to 70 percent of the black core is affected do other Parkinson’s symptoms become noticeable. Think of moving slowly, walking differently and the well-known ‘Parkinson’s mask’, where the face is less mobile. Dopamine deficiency also causes less visible symptoms, such as depression, anxiety and serious sleep problems. The impact on your life is therefore great. Fortunately, people can live a very long time with Parkinson’s disease, it does not kill you immediately. But the disease is experienced as a death sentence. It robs you of hope and perspective. You lose your zest for life.”
Medicines do not cure or slow Parkinson’s, but they can reduce symptoms.
“That’s right. Parkinson’s disease cannot be cured. The treatment is aimed at optimizing functioning. Physiotherapy focuses on safer movement, speech therapy helps with speech problems and occupational therapy provides support to enable you to carry out normal daily activities independently for longer. Dopamine replacements such as levodopa only suppress the symptoms. In addition, prevention of the disease is of course incredibly important. That’s why we need to better educate people about the benefits of exercise, healthy eating, drinking four cups of coffee a day and preventing concussions and other head injuries.”
One of the things you insist on is sufficient exercise. What does exercise do against Parkinson’s?
“Exercise helps to suppress the symptoms, just like medicine. There are also indications that the brain of athletes creates new connections between the affected brain areas and the healthy cerebral cortex. This gives hope that people can slow down the disease a little by exercising more. Moreover, we think that you could reduce the risk of developing Parkinson’s by exercising a lot if you are not yet ill. Furthermore, stress reduction is very important for people with Parkinson’s, which is why yoga and meditation are good.
Making music and other forms of art also seem to help, although we don’t yet understand exactly why. While people with Parkinson’s are very ‘adherent to therapy’, sustainable exercise proves difficult for currently healthy people with a genetic risk of Parkinson’s or for people with the first early symptoms of Parkinson’s, such as loss of smell, constipation or disturbed REM sleep. More than half of them do not exercise or exercise insufficiently. That is why we used part of the Stevin Prize that we won with our team to motivate people at increased risk to exercise more. We use an advanced app on the smartphone to promote movement and track steps, and the same smartphone also measures tremors and slowness. In this way we want to further deepen our understanding of Parkinson’s. The great thing is: everything can be measured remotely.”
You mention constipation as a risk factor?
“Yes, a disturbed microbiome may also play a role in the development of Parkinson’s. Almost all people with Parkinson’s have lazy intestines. To combat this constipation, they should drink two liters of water a day. If they don’t do this, the poop will accumulate in the intestines and ferment there. Those bacteria neutralize the medicines and that is of course not good. Many patients say that they drink enough. I always say: fill two empty coke bottles with water and put them on the counter. Only then do they realize that they do not always get those two liters.
Eating enough fiber is also important. Multiple studies show that the Mediterranean diet, which is rich in fruits, vegetables and whole grains, can have a beneficial effect. We are starting a new nutritional study this year to demonstrate this even more clearly. Nutrition is important for all your bodily functions. That is why it is so bad that a hamburger sandwich is cheaper than healthy food. I would like to see the impulse bins in the supermarket filled with organic snack tomatoes instead of all kinds of unhealthy junk.”
Speaking of organic: you see a clear link between pesticides and Parkinson’s?
“It is becoming increasingly clear that there is a link between the increase in the disease and exposure to pesticides. There are several studies that suggest a link between the most widely used and most controversial pesticide glyphosate and Parkinson’s. And yet in the Netherlands we spray 700,000 kilos every year on our fields and grasslands. They have conducted research in France, Canada and the US to see in which areas Parkinson’s is more common. These areas overlap very much with agricultural areas and in France, for example, with wine-growing areas.
The influence of glyphosate does not stop at the fence of a pasture. It spreads through the air. Researchers have found the toxin in nature reserves, drinking water sources and even in baby diapers. It just comes into your house. We breathe it in. And yet we cannot say with certainty whether glyphosate is safe for users or residents of agricultural plots, for example.”
You do not agree with the current method of research into pesticides?
“The entire admission policy is not sufficiently focused on safety with regard to developing Parkinson’s. Existing laboratory tests for determining neurological effects only study external characteristics in laboratory animals. They expose a mouse to a drug and then see whether it does not develop cancer and continues to hop around happily. Parkinson’s only occurs after serious damage has occurred in the brain, you do not immediately see anything on the outside. You therefore have to look in the relevant brain areas. Does the drug damage the substantia nigra?
That needs to be tested for. Pesticide manufacturers can say that they fall below the safety standard, but that standard is incorrect. And that’s where the problem lies: manufacturers keep slowing things down and conducting inadequate research. The safety of a drug should be demonstrated before any money can be made from it. Isn’t it crazy that that has now been reversed?”
The European food safety authority EFSA extended the approval of glyphosate for ten years last year. Does that make you despondent?
“No, I am an inveterate optimist. If we can provide evidence of the harmful effects in the coming years, glyphosate or other pesticides can be banned at that time. I’m on a mission to end Parkinson’s. And independent research into the effect of pesticides can help with this. We are doing everything we can to have this research carried out without interference from manufacturers.”