Here’s something most Americans can agree on: mornings are better with a fresh, steaming cup of joe.
At some point or another, you may have wondered if caffeine is your friend or foe. The truth is: caffeine affects everyone differently, thanks in part to our genetics. And if you want an estimate of how much is right for you, it’s important to look at the whole story.
First, let’s break down why your genes play an important role.
A major gene at play is CYP1A2, which helps control how quickly our bodies metabolize (break down) caffeine. There is one variant of CYP1A2 that may predispose someone to be a “slow metabolizer” and two variants that may make someone more likely to be a “fast metabolizer.”
This helps explain why some people just can’t start their morning without two cups of coffee, while others get the jitters from just one cup.
Why does it matter which group you fall into? People who metabolize caffeine slowly may be more likely to feel its negative effects (as in, caffeine may be more of a foe for them). On the flip side, fast metabolizers may be able to tolerate higher amounts.
It’s worth noting that the CYP1A2 is only one of many genes involved in caffeine’s absorption from the GI tract, distribution throughout the body, metabolization, and excretion (removal). The CYP1A2 enzyme is specifically involved in removal of caffeine from metabolic pathways.
Is caffeine your friend?
In one study, coffee drinkers who metabolize caffeine slowly (those with the “slow” variant of the CYP1A2 gene) had a higher risk of non-fatal heart attacks than fast metabolizers¹. The opposite was true for the fast metabolizers: drinking one to three cups of coffee a day decreased their heart attack risk.
Finding happiness at the bottom of a cup
If you drink coffee every morning, you know it can be a little unpleasant to engage in conversation before you’ve had your first cup. Neuroscience helps explain why: caffeine enhances the effect of dopamine, known as the brain’s “feel-good” neurotransmitter23
But not all people experience the same pleasure. For some people, especially those who are caffeine sensitive, just one cup of coffee can bring on jitters and anxiety.
Getting that pre-workout boost
Caffeine is thought to improve endurance and reduce muscle fatigue, especially during cardio-heavy exercises like running and cycling45678.
It’s worth noting that a pre-workout coffee may not jibe with people who are caffeine sensitive (this depends of course on the strength of the coffee and amount of caffeine). For them, caffeine can cause a racing heart, dizziness, and frequent bathroom trips—all of which could obviously get in the way of a workout.
Or is caffeine your foe?
Getting in the way of those zzz’s
This can be especially true for slow metabolizers who consume caffeine later in the day. Because they break down caffeine more slowly, it stays in their system longer and they feel the effects longer.
If you’re a fast metabolizer (and consume caffeine on a regular basis), you might not have any problems enjoying an afternoon coffee or tea.
Feeling the pressure
For some people, consuming caffeine causes a temporary rise in blood pressure. Researchers have investigated whether this means that having caffeine everyday can cause chronic high blood pressure.
One factor at play could be how fast you metabolize caffeine. In one study, slow metabolizers who drank coffee were more likely to develop hypertension (high blood pressure) than fast metabolizers9. That’s not good news: hypertension is a major risk factor for heart disease.
The tell-tale signs of addiction
It technically acts as a drug, after all, even though it’s been consumed safely by humans for thousands of years across many cultures. Caffeine speeds you up by enhancing the brain’s natural stimulants. Over time, the brain’s chemistry can change because it gets so used to the regular doses of caffeine.
How to tell that you may be hooked? One sign of a built-up tolerance is feeling like you need an extra cup of coffee to get the usual perk. If you forgo caffeine for a day and get stuck with brain fog and a headache, that’s another sign.
So should you grab an afternoon coffee or skip it altogether?
Finding out which variant of the CYP1A2 gene you have can help you decide.
And here’s the good news: it’s easy to learn which variant you have. Find out with your Personal Nutrition Blueprint, an easy, at-home nutrition test. In your results, you’ll also learn if you have several other nutrition-related genetic variants, like one that may predispose you to lactose intolerance.
The bottom line: as with most nutrition research findings, there is no good or bad, friend or foe. One cup of coffee might be just right for you, while three cups a day might be perfectly OK for someone else.