Two weeks ago Dr Amen, a brain disorder specialist, was on the Diary of a CEO podcast for a second time. And for a second time he told host, Steven Bartlett, to avoid drinking coffee.
The first time he linked it to Alzheimer’s Disease, the second time to Dementia.
The first time I let it fly… but now it’s time to set the record straight!
What is the consensus view of coffee’s impact on health?
In the first episode Dr Amen appears on the Diary of a CEO podcast, when Dr Amen speaks badly of caffeine, Steven Bartlett replies initially by saying
‘You are the first person I’ve ever spoken to who has a comprehensive and very believable hypothesis that caffeine has a side effect. I’ve asked my guests over and over again because people refer to caffeine as this miracle drug that comes with no cost.’
Some of these previous guests Steven speaks of are listed below with their views on coffee:
Tim Spector OBE. Epidemiologist, medical doctor and science writer. 5th October and Episode 209.
'Coffee is definitely a health food... all studies are showing, consistently, that you'll have less heart disease and will live longer if you drink coffee'.
‘Coffee can save your life.’
Matthew Walker. Author, scientist and professor of neuroscience and psychology at the University of California. Episode 228.
'The health benefits associated with coffee are undeniable - it's so strikingly clear that drinking coffee is so good for you.'
Max Lugavere. Health and science journalist and New York Times best-selling author of Genuis Foods. Episode 223.
'It honestly is hard to find a downside to coffee'.
After interviewing such prominent experts in the world of health and hearing them explain so emphatically how good coffee is for you, it was no wonder Steven was so surprised to hear Dr Amen is against it.
Does caffeine cause Alzheimer’s disease?
In the Diary of a CEO (DOAC) podcast episode 236 Dr Amen says
‘Low blood flow is the number one brain imaging predictor of Alzheimer’s. How do you get low blood flow? Caffeine.’
It seems that Dr Amen is claiming that caffeine (and he goes on to say coffee) is a cause of Alzheimer’s Disease (AD). Let’s see what the research says…
In August 2023 a study published in the Journal of Agricultural and Food Chemistry explained a mechanism through which espresso coffee offered protection against neurodegenerative disorders such as AD. It gets pretty technical, but it basically explains how tau proteins are involved in AD and how coffee and caffeine have biological properties which means they bind to tau fibrils protecting the brain.
In June 2023 a study published in Biomolecules (PMID: 37371547) discussed using caffeine for the prevention of Alzheimer’s Disease!
In June 2022 a review published in Molecules (PMID: 35744865) examined the neuroprotective effect of caffeine in AD. In their review of previous studies, they concluded by saying they ‘found strong evidence based on in vivo and in vitro studies that caffeine has some positive effects’ against AD.
There is definitely research demonstrating that caffeine reduces blood flow to the brain. But the most recent study showed that caffeine increases blood flow in the brains of mice at certain times of the sleep-wake cycle and so supporting brain health:
‘Increased blood flow during sleep caused by chronic caffeine may have implications for its potential neuroprotective effects through vascular mechanisms of brain waste clearance.’ – PMID 37780231 – September 2023.
Maybe coffee does affect blood flow to the brain, but assuming that causes AD is a leap too far.
I wonder if it’s something to do with hormesis? Hormesis is where your body adapts to a small amount of stress by getting stronger. Even exercise is a form of hormesis! As are cold exposure, sauna, fasting and many other things linked to keeping you healthier and disease free for longer.
Caffeine perhaps can (sometimes) restrict blood flow to the brain. But given all the positive studies on coffee and AD, the more likely outcome of this is that this small amount of stress on the brain has a hormetic response and makes your brain tougher and stronger and so more resilient to AD!
Does caffeine cause dementia?
In his second appearance on the DOAC podcast, Dr Amen this time indirectly says caffeine can cause dementia.
The section starts with Dr Amen explaining how the worst things for your brain are head injuries and sugar, before he then goes on to lump caffeine in with them.
Dr Amen: “Caffeine restricts blood flow to the brain.”
Steven Bartlett: “Do you think there’s a link between caffeine consumption and a shrinking brain?”
Dr Amen: “Yes”
Steven Bartlett: “Is a shrinking brain associated with dementia?”
Dr Amen: “I haven’t read any research that says there’s a connection between caffeine and dementia.”
“There’s a connection with sleep problems and dementia, and there’s a connection between caffeine and sleep problems.”
Wow, that’s quite a leap!
Blood flow to the brain we’ve tackled in the previous section.
When he says he hasn’t read any research connecting caffeine and dementia, what he means is he hasn’t read any negative research… but there is a TON of positive research. There have been many positive connections made between caffeine and dementia in research.
It’s unarguable that caffeine is associated with sleep problems… if consumed in ridiculously high quantities and too late in the day (for you personally). Read my previous article ‘How much coffee should you drink for maximum health benefits?’ to learn what the optimal amount and timing of coffee and caffeine is to achieve maximum health benefits while avoiding any negative effects.
But what isn’t fair is using that as a basis to claim that caffeine and coffee cause dementia. Besides, it’s not caffeine’s fault if we insist on abusing it by a) inventing energy drinks and b) by glorifying them to children!
Back to the point, does coffee cause dementia?
Conveniently, a systematic review was published in 2020 which considered 61 different studies looking at caffeine’s impact on cognitive decline and dementia (PMID: 33185612).
They concluded that
‘Our findings indicate that caffeine beneficially affects cognitive function and risk of dementia’
They also explain how the source of caffeine is key with a greater positive effect from caffeine in coffee and tea. They also discuss how you need to have enough caffeine to get the benefits, but not too much making it even more critical you consume the optimum amount of coffee – see my previous article on the optimal dose of coffee.
Perhaps the most exciting part for us at Exhale is that the review explains how coffee is especially protective of the brain because of its antioxidant effects caused by its polyphenols such as chlorogenic acid.
This is another reason why at Exhale we source, roast and lab test to find the highest levels of polyphenols and so maximising it’s antioxidant power. Read our lab tests to see how just one brewed cup of Exhale Coffee has the same antioxidant power as 1.8kg of blueberries or 55 oranges!
The research seems clear to me - coffee doesn't cause Alzheimer's or dementia and may actually help them. It would be great to see Dr Amen separate out caffeine consumption in coffee from the caffeine in energy drinks which may have a different effect (I didn't research that for this blog).
Conversations like this would have a far bigger impact on the health of the population if instead they were focused on using science-based evidence to help steer people towards having a healthier relationship with coffee and caffeine. Which is why it’s our mission at Exhale to educate on how to get the many health benefits of coffee that have actually been demonstrated by science, while avoiding any possible negative effects.
Finally, it would be awesome to also hear a distinction made between the quality of coffee we consume instead of throwing out the good with the bad!