Why is coffee sooooooo good?
I love coffee. It’s delicious, aromatic and warming. And it comes in so many varieties! Lattés, Americanos, Iced…Alcoholic! But most importantly, it provides that much appreciated, and sometimes essential, pick-me-up when the day is beginning to drag.
And I’m not alone.
The component of coffee that gives us that ‘buzz’ is caffeine, and caffeine is the world’s most popular psychoactive drug. ‘Psychoactive’ describes a group of drugs that cause a temporary increase in mental function, and stimulates activation in the cells in the brain. When coffee is consumed, it can therefore increase cognition (e.g. problem solving, alertness and attention) as well as memory.
The effects of coffee might also be long-term – there is increasing evidence that regular consumption of moderate amounts of caffeine (3-5 cups of coffee a day) over many years can prevent age-related cognitive decline, and as I mentioned in my previous post Alzheimer’s Disease – Explained!, there is also some evidence that suggests caffeine can reduce the risk, or delay the onset of, Alzheimer’s Disease.
So what is happening in the brain when you drink a cup of delicious coffee?
Our brain cells have many different ‘detectors’ or ‘receptors’ that are specific to particular signals in the brain, so that they know how to react in response to different situations. One of these signals (or ’neurotransmitters’) is a chemical called Adenosine. When Adenosine attaches to the receptors that are designed to detect it (unsurprisingly called ‘Adenosine receptors’), activity within the cell is inhibited.
Inhibiting cell function in the brain sounds like it might be a bad thing, but actually activity in the brain needs to be ordered and carefully regulated in order to communicate meaningful information. That means that there must be a balance between stimulation and inhibition.
Caffeine is also able to attach to Adenosine receptors, but as it is not Adenosine, it does not have the same effect on the cell. Because caffeine is attached to the receptors, it is ‘blocking’ (or ‘antagonising’) the attachment of Adenosine. As the inhibitory Adenosine signal can no longer be detected, this causes increased cell stimulation and activity.
This increased activity has been found to be present in the parts of the brain that have been linked with cognition and attention, and may be why we may experience clearer thinking and feel more awake after a strong cup of the good stuff.
Blocking Adenosine receptors also causes an increase in another neurotransmitter, Dopamine. Dopamine acts as a reward system in the brain, so when it is increased we feel pleasure and are compelled to repeat the behaviour that gave us that good feeling (i.e. running down to our favourite café and sipping on a steaming cup of java).
But it’s not all good news
So its sounds like coffee, and importantly caffeine, is some kind of wonder drug that makes us happier and cures all ailments! Right?
Well, not exactly. While there is a lot of evidence for the positive effects of both caffeine and coffee, much of this research has been carried out in rats and mice as it is difficult, and ethically questionable, to manipulate the amount of coffee a group of people drink daily over the course of their adult lives. Simply, we just don’t know enough – how much is a useful amount of caffeine? How much is too much (caffeine overdose does exist and can be very dangerous)? When is the best time to start drinking it?
Too much caffeine early in life can also be damaging; caffeine easily crosses into the placenta, where it can have large effects on the developing foetus, as it cannot yet be efficiently processed. Even in teenagers the brain is still developing, and too much caffeine has been found to increase anxiety and change the number of Adenosine receptors found in the brain (albeit in rodents).
However, with all its cognitive perks in healthy adults, and the joy that comes from drinking it, it looks like coffee is going to be enjoyed in its many delightful forms, and will stay one of the most popular drugs in the world!