This is Your Brain on Coffee

By LT Ingram, Northwestern '21, 04/01/2021

Coffee, the perfect way to start the morning. You are likely familiar with the burst of energy and mood boost that comes with drinking coffee. But have you ever wondered how this happens? Join me for a brief tour of the effects of coffee on the brain, which will hopefully provide some answers for why coffee makes you feel the way it does.

Why does coffee give me energy and help me stay awake?

The caffeine within coffee is a valuable source of energy for college students, night workers, and new parents alike. Caffeine is the stimulant that is responsible for coffee’s ability to increase alertness and ward off sleep. The reason caffeine is able to do this is due to its chemical mimicry of adenosine. Adenosine is one of the key neuromodulators in the human body that is able to signal when we’re running out of energy and need to sleep. Adenosine results from the breakdown of Adenosine Triphosphate(ATP), which is the main source of energy for your cells. After ATP is used up by the cells, it breaks down into adenosine and enters the bloodstream. As more adenosine builds up over the course of the day due to cells continuing to use energy, it begins to activate adenosine receptors. When activated these receptors are activated, feelings of drowsiness set in. However, when caffeine is consumed, due to the similarity in its molecular structure, caffeine is able to bind to the receptors and prevent adenosine from attaching and signaling drowsiness. Caffeine doesn’t do anything to remove the adenosine or prevent it from building up. This is why the dreaded caffeine crash occurs, as once the caffeine wears off, the adenosine is able to bind again and signal drowsiness. Only sleep is able to clear out adenosine, so after fueling yourself with cold brew to pull an all nighter to cram for an exam, make sure you get some sleep. Your body and brain will thank you.

Why does coffee make me feel happier? Why do I get grumpy when I don’t drink it?

Roughly 30 minutes after you first consume coffee, you may feel like your mood lifts up and it's not just your imagination. Dopamine is a neurotransmitter that is responsible for pleasure. It’s one of the main neurotransmitters responsible for the famed runner’s high. It also gets released when we eat food we enjoy, so that’s why digging into a bowl of ice cream makes us feel so much better. Drinking coffee doesn’t increase the amount of dopamine our body produces. Instead, it prevents the reuptake of dopamine by the neural cells through blocking the dopamine transporter. This means dopamine has more time to attach to receptors and activate them, producing a pleasurable feeling. Overtime, your body adapts to this shift in its dopamine receptivity and may modify its own dopamine production to be lower. This is why caffeine withdrawal can make people irritated and grumpy, because they are having lower than normal dopamine activity, as they’ve come to rely on coffee to produce their dopamine. If you’re planning to lower your caffeine intake, make sure to do it gradually to avoid feeling irritated and to avoid headaches.

Can coffee help me stay healthy in the long run?

Besides the immediate effects of improved mood and alertness, drinking coffee can improve your brain health. Coffee is rich in polyphenols, a type of organic compounds. Polyphenols have anti-inflammatory benefits, which can help prevent neurodegenerative diseases such as Alzhemier’s and dementia. This is thought to occur through the inhibition of neuro-toxic proteins build up, such as beta-amyloid. When these proteins build up, they form plaques and tangles which block the communication between neurons. The extent of the protective factor of coffee has varied from study to study, but many found a roughly 20 percent decrease in risk, with some finding up to 65%. Coffee consumption has been linked to lower levels of Parkinson’s disease, which results due to the death of dopamine expressing neurons in a region called the substantia nigra, which is responsible for motor control. Coffee drinkers have been shown to have a much lower risk for Parkinson’s, but only those who drank caffeinated coffee. As a result, it appears to be a combination of the coffee’s beneficial compounds and caffeine that help reduce the risk. Next time someone tells you you’re drinking too much coffee, tell them it's for the benefit to your health. After all, who can argue with wanting to be healthier?