Updated: Apr 30
The evidence that coffee is neuroprotective is strong, and the ideal time to drink two or three cups one to two hours after you wake up and before 4pm.
When I moved to New Zealand 12 years ago, I was surprised at the abundance of coffee shops. My wife loves coffee, so she was amazed at the range of choices and discovered flat whites.
I soon learned that coffee culture in New Zealand is more than a way to get a caffeine fix. Coffee is a social experience. Kiwis often meet for coffee in cafes, where they catch up with friends, but it is also entrenched in work culture. Work meetings often appear as 'Let's grab a coffee' invites.
Coffee plays a central role in people's lives, which is great when you drink coffee – but I didn't. The few times I tried, it tasted too bitter, and the aftertaste would linger for hours. I wasn't a fan.
I’ve changed my mind. Why? I followed the science of the health benefits of coffee. I’m a neuroscientist studying the early effect of Parkinson’s disease, a degenerative disorder that affects the nervous system and causes movement problems.
It occurs when the neurons responsible for producing dopamine die off. Dopamine is an important neurotransmitter involved in movement and memory, enabling you to feel pleasure, satisfaction and motivation. As the levels of dopamine decrease, people with Parkinson's disease experience tremors, stiffness, and difficulty with coordination and balance. They may also have trouble with speech, loss of smell, sleep problems and depression.
During my research, I learned that people drinking coffee were less likely to develop Parkinson's disease. This was not a single hot-off-the-press news article of the latest research. Study after study demonstrated that coffee drinkers develop Parkinson's disease later than non-coffee drinkers.
This inverse relationship between the consumption of caffeine and the development of Parkinson's disease was first tested in 1975. Since then, other clinical studies have documented improvements in motor deficits in Parkinson's patients who drink coffee.
Reaching for that coffee when you get out of bed may be tempting, but waiting for the second hour after waking up will make you feel more alert for longer.
Intrigued by overwhelming evidence, I did the only thing a scientist could do. I started drinking coffee.
There is still a perception that coffee is a pleasure we could do without, and some research advising against caffeine and bad news about coffee always generates headlines. But though the underlying mechanisms are still an active and emerging field of research, the evidence for caffeine's neuroprotective potential is robust, along with evidence of it reducing the risk of Type 2 diabetes, liver cancer, cirrhosis, gallstones, depression, melanoma, and prostate cancer.
Drinking two or three cups of coffee daily not only reduces the risk of Parkinson's disease but also caffeine also has additional neuroprotective capabilities that can reduce disease progression.
The lifetime risk of developing Parkinson's disease for the general population is 1 to 2 per cent. The risk increases with age, with the highest risk being in individuals over the age of 60. Additionally, men are slightly more likely to develop Parkinson's disease than women.
Study outcomes vary in how much risk reduction is associated with coffee drinking. Overall, these studies suggest that regular coffee consumption is associated with a lower risk of developing Parkinson's disease, with risk reductions ranging from 30 per cent to 80 per cent. Practically all studies show a risk reduction for Parkinson's.
Clinical trials with Parkinson's patients have shown caffeine consumption decreased motor symptoms (lower resting tremor and the severity of it) and fatigue. Some caffeine studies even suggest a possible improvement in cognitive impairments in patients with Parkinson's disease.
Mouse studies further reinforce that caffeine delays the onset of Parkinson's disease in a dose-dependent manner. However, evidence suggests it is more beneficial in men than women, with no advantages for women undergoing hormone replacement therapy. Drinking coffee is, therefore, not one size fits all for Parkinson's disease.
How might caffeine work? Research shows the beneficial effects of caffeine are caused by a series of events that counter the role of adenosine receptors, which promote sleep-wake regulation and help reduce inflammatory responses.
During the day, the amount of adenosine in our central nervous system increases. Adenosine molecules bind onto adenosine receptors, whose activation makes us feel tired. Caffeine, however, blocks adenosine receptors, inhibiting this natural mechanism and reducing tiredness. This also prolongs the presence of dopamine in our brains by slowing down its natural breakdown, which plays a role in its neuroprotective effects against Parkinson's.
But timing is everything. Reaching for that coffee when you get out of bed may be tempting but waiting for the second hour after waking up will make you feel more alert for longer.
This is because when we wake up, the hormones that promote alertness and focus, cortisol, are produced at high amounts 45 minutes after waking up. Drinking coffee while cortisol levels are still high competes with cortisol and lessens its effect. This tricks the body into thinking it needs less cortisol to feel alert so it will produce less in the future. Tolerance to coffee increases, so more coffee is needed to feel awake to compensate for the decreased cortisol production. That's how we can become dependent on caffeine.
Caffeine stays in your body for four to six hours, so drinking coffee after 4pm is not a good idea. It will interfere with the body's natural circadian rhythm, making it harder to sleep. The ideal time to drink coffee is one to two hours after you wake up and before 4pm.
Even though much is left to unravel about caffeine and Parkinson's disease, there is good evidence that having that daily coffee is one of the things everyone can do, along with getting enough sleep, eating well, and getting regular exercise. So enjoy that hot brew this morning … or any time before 4pm.
© Mikayla Ibarra & Dr Victor Dieriks