Recent study by NNI shows coffee consumption reduces Parkinson’s disease risk in people genetically predisposed to the ailment.

Coffee lovers must be rejoicing now that a study by the National Neuroscience Institute (NNI) has shown that downing just two cups of kopi a day can reduce the risk of Parkinson’s disease (PD) by four to eight times in people with Asian gene variants linked to the condition.

What is PD?

PD is a progressive disorder that affects the nervous system. Although it is most commonly associated with tremors — rhythmic shaking of a limb, often at the hand or fingers — it can manifest in other ways: slowed movements, loss of automatic movements, rigid muscles, and poor balance.

PD is the fastest growing neurodegenerative condition around the world. A recent study by NNI showed that 26 per cent of the local older population exhibit mild Parkinsonian signs.

Research impetus

Professor Tan Eng King, Deputy Chief Executive Officer (Academic Affairs) and Senior Consultant, Department of Neurology, NNI, and the study’s principal investigator, shared that caffeine is known to decrease inflammation of neurons in the brain. “Coffee and tea are the most widely consumed beverages globally and here in Singapore,” he added. “Because these beverages have been linked to neuroprotection, this provided the impetus for us to investigate its interaction with Asian-specific PD-linked gene risk variants in our population.”

The key question, Prof Tan said, is whether caffeine consumption can reduce the PD risk posed by these genetic variants. If the study showed that link, then lifestyle modification can be added to the arsenal of weapons to combat PD. “Tea and coffee are readily available and culturally accepted in most Asian societies, and consuming caffeine within normal limits offers an easy, pleasant and sociable way for people to potentially reduce their risk of PD.”

Read more: Tremors are a sure sign of Parkinson’s disease, true or false? Click here to find out. 

Study details

There are two known Asian gene variants that occur most frequently in East Asians. Up to 10 per cent of the Singapore population carry one of these variants. The study, which involved 4,488 subjects, showed that people carrying these variants have a 1.5 to 2 times higher risk of developing PD.

The subjects’ average daily caffeine intake was 448.3mg among PD cases and 473.0mg in the healthy controls. This amount of caffeine is found in four to five cups (235ml per cup) of Western-style brewed Arabica coffee beans or two cups of traditional Singapore kopi made from Robusta coffee beans, which have higher caffeine content than Arabica coffee beans. (400mg of caffeine a day is generally regarded as safe for most healthy adults.)

Higher doses of caffeine appeared to confer stronger neuroprotection, but even subjects who drank less than 200mg of caffeine per day still reduced their PD risk. In fact, tea and coffee drinkers who carry the PD gene lower their risk of getting PD to below that of non-caffeine drinkers who do not carry the gene.

Results of the study were first revealed at the 10th Singapore International Parkinson Disease and Movement Disorders Symposium, which was held in September 2023.

Next steps

So if a person does not have the gene variants, will dosing on coffee keep PD at bay? Based on current epidemiological evidence, it is useful to take coffee and tea in moderate amounts regardless of PD risk; in those at high risk such as gene carriers, it is even more useful. Prof Tan added that the epidemiological observation does not differentiate whether it is the caffeine only or caffeine plus something else, such as other antioxidants, in coffee and tea that is giving the protection.

But the next step for him and his team, shared Prof Tan, was “to conduct biological studies in human cell and animal models to decipher the underlying mechanisms, and also to conduct more clinical studies to examine the caffeine interaction with other genetic variants”. He would also like to conduct further studies that follow patients over a longer period of time. “This will help to determine the exact relationship between doses of caffeine consumption and progression of PD and other related diseases. With more information, we can then provide better management protocols for patients and those at risk of getting PD,” he said.

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