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It’s the world’s most widely consumed psychostimulant. What you need to know about your brain and coffee.

Every year, around 400 billion cups of coffee are consumed worldwide and with 42 coffee beans needed for every cup of espresso, that’s a lot of beans. No wonder in the States, coffee is the largest food import and the second most valuable commodity after oil.

We love our coffee, for its beautiful aroma, the taste, for making us feel good and of course for getting our neurons humming. We drink it; rub the grounds on our skin and some even choose to have coffee enemas but however you take your coffee what we look for is that extra little zing in our step and feeling of greater alertness. There is even some suggestion that coffee works as a cognitive enhancer.

The one thing guaranteed as a coffee drinker is that a short while after enjoying that first cup, you’ll be back for another. So let’s take a look at what keeps us coming back for more, discover whether the myths live up to the hype and determine if it is good for our brain.

Caffeine boosts memory after learning

One study published in Nature Neuroscience showed that consuming 200mg of caffeine (one strong cup of coffee) enhanced memory consolidation after learning some information for up to 24 hours in a group of people aged 18-30 years. The effect wasn’t seen with 300mg, so there appears to be a dose-effect. How this works isn’t known, it could be to do with paying better attention, or it might be something to do with lessening the forgetting effect. Either way, it’s encouraging to think we’re doing something good for our brain, though the results need to be verified with more research because the numbers of subjects in this study were small.

Caffeine boosts adrenaline and dopamine levels

It’s a good idea to go easy on your total caffeine consumption per day as too high a dose is linked to some unpleasant physiological symptoms and can play havoc with sleep patterns. That’s because caffeine stimulates the release of adrenaline, one of our stress hormones.

(As for those so-called energy drinks that contain high levels of caffeine, these have in a number of instances when consumed to excess proved lethal. Along with sugar-laden sodas, energy drinks deserve to be relegated to the unfit for human consumption bin. Yes, that’s my opinion, and I’m sticking to it.)

Dopamine is the brain chemical linked to our reward circuitry and associated with motivation and pleasure. Caffeine reduces the reuptake of dopamine by the brain so we feel good and naturally want to extend that feeling for longer. I’ll have another cup now, please.

How much coffee is safe?

Moderation is the way to go and individual tolerance varies. Sticking to about 300 – 400 mg of caffeine per day (that’s three to four cups) is fine for most people.

If you’ve ever experienced caffeine withdrawal symptoms, you’ll know just how unpleasant these are. They are a potent reminder that caffeine is indeed a drug with withdrawal leading not only to a nasty headache but also greater fatigue, an increase in blood pressure, a reduction in cerebral blood flow and difficulty in focusing.

Why does caffeine stop us from sleeping?

During the day our brain releases an increasing amount of an inhibitory neurotransmitter called adenosine. This works to gradually suppress neuronal activity preparing us for sleep at the end of the day. Staying awake too long is bad for cognition, memory and learning.

Caffeine works as an antagonist directly competing with adenosine receptors on our neurons thereby blocking adenosine from exerting its calming effect.

Sleep clears the adenosine out from the brain meaning we are then set up to be more alert again at the beginning of the day.

If caffeine is perpetually taking our adenosine parking spots the brain responds by creating more adenosine receptors (clever brain!) but that also means you have to drink more coffee to experience the same level of arousal. This is the same principle by which addictions to other drugs develop.

The half-life of caffeine is about six hours. This means the cup of coffee you drink at 3 pm will still have 50% of the caffeine exerting its alerting effect at 9 pm. Which is why If you’ve noticed caffeine interferes with your ability to sleep it’s recommended to keep your coffee drinking to the earlier part of the day.

Busy day? Try a coffee nap

While this might sound a complete oxymoron, it works.

The caffeine in our coffee takes about 20 minutes to kick in. So drink up and then set your alarm to take a 20-minute power nap to keep you in the light phase of sleep. On waking you then have the double bonus of the sleep’s cognitive refreshment plus the heightened alertness from the coffee. Ka-boom!

But remember the ideal time is probably shortly after lunch so as not to interfere with normal sleep.

You may have read that coffee is high in antioxidants and that’s true. However so are many other foods with a far higher nutritional value, so look for your antioxidants in those great cognitive boosters such as leafy greens and deeply pigmented berries.

Caffeine is neuroprotective

The good news is that some studies have demonstrated that drinking coffee is associated with a reduced risk of Alzheimer’s and Parkinson’s disease.

One such study showed that having higher blood caffeine levels was linked to a lack of progression to full-blown dementia in those subjects already identified with mild cognitive impairment.

Word of warning: while some studies have suggested coffee drinking to be neuroprotective this is NOT a cause and effect scenario. Drinking coffee won’t prevent you from developing a neurodegenerative disorder, but the good news is that drinking three cups a day (especially if you are a woman aged 65-80) has been associated with a lower risk for dementia.

It appears that a little of what you fancy can indeed do you good. The caffeine in your coffee (and tea) will help you stay alert and feel good, it may help you to learn more effectively and it may even help protect you against cognitive decline.

Which all sounds like a very good reason to sit back, relax and enjoy your morning cup of Joe.

Dr Jenny Brockis

Dr Jenny Brockis is a medical practitioner and internationally board-certified lifestyle medicine physician, workplace health and wellbeing consultant, podcaster, keynote speaker and best-selling author. Her new book 'Thriving Mind: How to Cultivate a Good Life' (Wiley) is available online and at all good bookstores.

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