Two early-morning long blacks. A lunchtime flat white (especially if I’m near a cafe). And sometimes a sneaky pick-me-up afternoon espresso.
Time to come clean: that’s a typical day for me.
I guess to many of you that might seem like WAY too much caffeine. But I’m not too concerned because neuroscience shows that coffee has neuroprotective effects.
Neuroscience and coffee.
According to international statistics, the highest per capita coffee consumption in the world is among Finns with 12.0 kg in year 2007, followed by 9.9 kg among Norwegians, and 8.7 kg among Danes.
Some studies of Finnish coffee aficionados found that drinking two or three cups of coffee a day was associated with a decreased risk of developing Alzheimer’s disease.
A similar story was found when US neuroscientists followed a group of coffee-drinking 65 to 88 year-olds who were just starting to show the first signs of memory loss.
The coffee-drinking volunteers were assessed neurologically over the course of two to four years, but rather than relying on the recall or dietary surveys of coffee intake, volunteers blood caffeine levels were monitored at each visit to the lab.
The results were intriguing — moderate levels of caffeine in their blood (equivalent to about three cups a day) were associated with a reduced risk, or slower decline towards dementia.
And (this is the important bit) these were people who were already showing signs of memory loss, or cognitive decline. Coffee appeared to slow the dementia process.
US neuroscientist Dr Gary Arendash who conducted the blood caffeine study says,
“Coffee is inexpensive, readily available, easily gets into the brain, and has few side-effects for most of us. Moreover, our studies show that caffeine and coffee appear to directly attack the Alzheimer’s disease process.”
Dr Arendash is also studying the effects of caffeine on the brains of mice with Alzheimer’s disease. He’s found that adding caffeinated water to rodents’ diet results in big improvements. The mice perform better on short-term memory and thinking tests. But only if they get enough caffeine.
Dr Arendash is convinced that caffeine is protecting his brain:
“I drink five to six cups a day, religiously”
It seems it’s not just your brain that benefits from coffee. In other research published in the prestigious New England Journal of Medicine, coffee drinkers were less likely to die from the following:
- heart disease
- respiratory disease
- injuries and accidents
BUT it didn’t protect against cancer.
Coffee consumption was inversely associated with total and cause-specific mortality. Whether this was a causal or associational finding cannot be determined from the data.
Dr Neal Freedman the scientist who lead the latest study says,
“Coffee is one of the most widely consumed beverages … but the association between coffee consumption and risk of death has been unclear. We found coffee consumption to be associated with lower risk of death overall, and of death from a number of different causes,”
It’s worth pointing out that that this does not mean coffee stops you from dying … it’s not that simple. As Dr Freedman says,
“Although we cannot infer a causal relationship between coffee drinking and lower risk of death, we believe these results do provide some reassurance that coffee drinking does not adversely affect health.”
How does coffee protect the brain?
Coffee is a complex mixture of biologically active chemicals including:
- caffeine (of course)
- chlorogenic acid
In fact, coffee is the world’s major food sources of antioxidants which protect the cells from damage, disease and aging.
Caffeine acts on the brain by linking up to molecule on the surface a particular type of brain cell called a cholinergic neuron. The cell surface molecule modulates the neuroprotective effects of caffeine. And, caffeine also triggers the same molecule to decrease proteins known to gather in the brains of Alzheimer’s disease patients.
Interestingly, drinking tea shows no link with dementia or Alzheimer’s disease risk reduction (this was found in the Finnish study and in similar studies elsewhere). This could be due to lesser caffeine content in tea, or the fact that other components than caffeine in coffee confer the protective effect.
So, coffee protects the brain, but surely it can’t all be good news?
Coffee-lovers amongst are well aware of the stimulating effects of caffeine. We feel more alert, energetic and have greater powers of concentration (which is kind of the point, really!). But higher doses can cause negative effects such as anxiety, restlessness, insomnia, and a racing heart.
Also, coffee drinking can’t offset genetic risks. Alzheimer’s disease, for example, is incredibly complicated. Exercise, good nutrition, social connectedness and a variety of other lifestyle factors may be protective. BUT a person’s risk is also determined by genes. No one behaviour or ‘magic bullet’ — like coffee drinking — can erase that risk.
If you’re a coffee drinker. You know the drill – too much coffee too late in the day will wreck your sleep. And a poor night’s sleep isn’t so good for boosting your mental powers the following day.
So, when you next wander into your local cafe for your daily dose, do so without the guilt, perhaps cut down on coffee later in the day, and know you’re doing your bit to maintain your brain health and wellbeing.
Coffee consumption seems generally safe within usual levels of intake, with summary estimates indicating largest risk reduction for various health outcomes at three to four cups a day, and more likely to benefit health than harm.
In particular, coffee intake was inversely associated with all-cause mortality, incidence of and mortality from cardiovascular disease, and incidence of cancer, non-alcoholic fatty liver disease, cirrhosis, and diabetes.
Robust randomised controlled trials are needed to understand whether the observed associations are causal. Importantly, outside of pregnancy, existing evidence suggests that coffee could be tested as an intervention without significant risk of causing harm. Women at increased risk of fracture should possibly be excluded.
Image credit: @rsseattle flickr.
Some of this article was originally written for Starts at Sixty….but I’ve tweaked it for my blog.
About Dr Sarah
I’m an Oxford University-educated neuroscientist, presenter of ABC Catalyst, director of The Neuroscience Academy, and author of The Women's Brain Book. The neuroscience of health, hormones and happiness.
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