Your Brain on Coffee?

Do you think of coffee as “the devil’s brew,” liquid gold, “god in a cup,” or just your morning wake-up call? Do you think it’s good for you or bad for you? Are you addicted to it? Are you trying to quit or cut back? How long since your last cup? Are you drinking coffee right now?

Coffee is widely consumed but just as widely misunderstood. Many myths about it have proven hard to dispel in spite of the research debunking them. Coffee is considered to be a stimulant that is addictive. You’ve probably heard someone comment about coffee being his or her drug of choice. Maybe you’ve said it yourself.

Caffeine passes through the blood brain barrier, so it directly affects the brain. Scientists can’t fully explain all the mechanisms involved, but there is growing consensus about several things.

1. Caffeine isn’t a stimulant the way cocaine or amphetamines are.

When caffeine enters the brain, it binds to and blocks adenosine receptors (without activating them). Adenosine is a neurochemical produced by neurons as they fire. As adenosine levels build up, you begin to feel sleepy or at least less energetic. With caffeine blocking the adenosine receptors, your nervous system doesn’t respond the way it normally would. Instead of feeling drowsy, you continue to feel alert.

 

2. Caffeine can become a habit, but it isn’t addictive in the strict definition of the term.

Another thing happens when caffeine blocks adenosine receptors: more glutamate and dopamine are released. These are both excitatory neurotransmitters that are also involved in memory and learning. Dopamine is part of the brain’s reward system. The hit of dopamine you get from caffeine is another reason you can become habituated to drinking coffee or other caffeinated drinks. You feel good and your brain urges you to do it again.

Caffeine can change brain structure in terms of the number of adenosine receptors. And some people experience withdrawal symptoms when they stop using it. However, not everyone experiences withdrawal symptoms—and some of those symptoms may be all in your mind. It turns out that reactions to caffeine vary widely and are influenced by both genetics and expectations. If one of your parents is sensitive to caffeine, you probably are, too. Likewise, if you have a parent with a high tolerance for caffeine, you probably do, as well.

3. Caffeine doesn’t keep most people who drink it up at night.

The half-life of caffeine is about five or six hours, although it varies from person to person and with different conditions (health, age, weight, body type, metabolism, pregnancy, etc.). As long as you don’t drink coffee late in the day, you probably will be able to sleep just fine. On the other hand, some people can fall asleep right after having a cup of coffee. In fact, one recommended method for boosting your energy mid-day is to have a cup of coffee and then take a nap. The combination of the two works better than either one alone. [I experienced this once, albeit unintentionally, and can vouch for the results.]

4. Caffeine does help you maintain your attention or focus on tasks, but only on routine tasks or activities that are kind of boring and not particularly challenging.

It can help you tune out distractions, which means it may be helpful for people with ADD or ADHD but not for people with OCD. Caffeine can help you work faster. However, if you want to focus on a creative activity or something that requires conscious (System 2) attention—“real thinking” or “pure thought,” as some refer to it—caffeine won’t be much of a help. It can even be a hindrance.

5. Caffeine can improve your long-term memory by helping your brain consolidate those memories.

The trick is to consume it after you learn something rather than before. This makes sense given caffeine’s effect of blocking adenosine receptors and allowing for the release of more dopamine and glutamate, both of which are involved in learning.

But wait…there’s more!

The conclusion of a 2010 detailed literature review by M.J. Glade revealed that a moderate amount of caffeine:

• Increases energy availability
• Increases daily energy expenditure
• Decreases fatigue
• Decreases the sense of effort associated with physical activity
• Enhances physical performance
• Enhances motor performance
• Enhances cognitive performance
• Increases alertness, wakefulness, and feelings of “energy”
• Decreases mental fatigue
• Quickens reactions
• Increases the accuracy of reactions
• Increases the ability to concentrate and focus attention
• Enhances short-term memory
• Increases the ability to solve problems requiring reasoning
• Increases the ability to make correct decisions
• Enhances cognitive functioning capabilities and neuromuscular coordination

The key for most people is moderation, which means limiting coffee consumption to about three eight-ounce cups a day. Not all eight-ounce cups of coffee contain the same amount of caffeine, however; nor do they contain the same amount of CQA (caffeoylquinic acid), the compound in coffee that may be responsible for some of its beneficial effects. Hopefully, we will eventually be able to get that information at our point of purchase. In the meantime, my brain says enough thinking and writing about coffee. It’s time to enjoy some!