What does coffee really do in your body?

Most of you are probably too young to be drinking coffee every morning, but you may have witnessed adults in your family get really cranky when they don’t get their morning cup. For people in professions that require them to be up late at night (like us journalists!), coffee is even more important.

It is often said that coffee keeps you awake. That’s true, but do you know how?

It all comes down to a chemical called caffeine that coffee contains. Caffeine is also present in tea, soft drinks and energy drinks. The trouble with consuming too much caffeine is that you get addicted to them, just as any other drug. That explains the crankiness. Sugar content is also another problem.

Nevertheless, caffeinated beverages are among the most popular in the world, presumably because of how alert it makes us.

How does caffeine do this?

Caffeine is something of a trickster. It has a structure that is similar to another chemical called adenosine. Now adenosine is a natural substance found in our body which plays an important role in making us sleepy. When adenosine molecules bind to adenosine-receptors on nerve cells, the brain’s activity slows down (making you sleepy) and blood vessels widen (allowing more oxygen to reach you while asleep).

Now when we consume coffee, caffeine molecules begin circulating in our body. Because caffeine has a structure similar to adenosine, it fools the adenosine-receptors on the nerve cells into thinking that it is adenosine. The caffeine hence bind to these receptors just as adenosine would.

Soon, adenosine runs out of receptors to bind to as caffeine has taken its place instead. Though caffeine looks like adenosine, it does not have the same sleepy properties as its look-alike. Since fewer receptors in our nerve cells have adenosine bound to it than usual, we feel more alert and our brain activity is in fact faster than normal.

The pituitary gland in our brain senses that something is going on, and as in the case of stressful situations, it reacts by secreting hormones that signal the adrenal glands to produce adrenaline. Adrenaline increases the flow of oxygen to muscles and generally makes us more alert and active. Voila! The coffee has done its job.

The first President of the United States of America and coffee have an interesting connection. If you can do a bit of research and find out what the link is, tell me at

nandita.j@thehindu.co.in

and I’ll tell you if you got it right.