If I have too much coffee at work, I know what’s coming — and it’s not pretty.
Imagine a hamster, hopped up on energy drinks, going nuts on a spinning wheel. That’s what my brain feels like if I overdo it on the java.
That feeling will go well into the evening, well past my normal bedtime, until I hate myself for thinking this time would be different because I must be building up a tolerance now.
Turns out that I — and many other people — may never be able to drink as much coffee as some of our co-workers.
Because there are two kinds of people in the world: slow and fast caffeine metabolizers. And I’m in the first group.
Read on to find out how all of this works — and what it means for you.
The science behind coffee consumption
There is a bounty of research into how humans process caffeine, as this New York Times article points out.
The basics come down to genetics.
CYP1A2 is a gene. It codes for an enzyme that helps break down caffeine. This gene comes in two versions, according to Nature. People with one or two copies of CYP1A2 (a.k.a. the “slow” gene) metabolize caffeine slowly, while people carrying one or two copies of the “fast” gene metabolize caffeine more quickly.
How coffee consumption impacts people depends on what version of the “caffeine gene” they carry.
The research into this started coming out about 10 years ago Ahmed El-Sohemy, a professor at the University of Toronto.
El-Sohemy and his team found that slow metabolizers who drank multiple cups of coffee daily were more likely to have suffered a heart attack, according to Nature. On the flip side, one to three cups of coffee each day actually seemed to protect fast metabolizers.
What type of metabolizer are you?
So, how can you determine if you’re a Usain Bolt of metabolizing coffee or a bit more of a sloth?
Likely, your body is giving you signs that can clue you into where you fall on the great coffee divide.
Slow metabolizers can get jittery and stay wired up to nine hours after drinking caffeine, according to Precision Nutrition. Meanwhile, fast metabolizers simply feel more energetic and alert for a couple hours.
“Want a quick and easy test of your coffee consumption? Ask yourself how you feel physically, mentally, and emotionally a few hours after you drink some… as well as if you miss your daily dose.”
— Brian St. Pierre for Precision Nutrition
For those who want another detective to scour their body for clues, there’s always the option of a genetic test. These tests can tell people which coffee-drinking camp they fall into — for a fee.
El-Sohemy is on the record as saying that this is “the only way to know” what type of metabolizer you really are.
Anahad O’Conner, who wrote the New York Times article referenced at the beginning of this post, took the test through FitnessGenes.
Why it’s good to know your optimal intake
We already know drinking too much coffee can be bad for your health if you’re a slow metabolizer — for example, by making you more prone to suffer a heart attack — thanks to professor El-Sohemy’s research.
But not knowing your coffee intake sweet spot may also have negative repercussions in the workplace. If you’re taking in more caffeine that you can handle, the proven benefits that many people experience from coffee may not apply to you.
And since slow metabolizers can feel those post-caffeine jitters for hours, you may find yourself spending your evenings tossing and turning, and ultimately getting too few hours of sleep.
Not getting enough zzz’s can result in poor health and, in the workplace, reduced efficiency, productivity, errors and accidents, according to Healthy Sleep, a resource from the Division of Sleep Medicine at Harvard Medical School and WGBH Educational Foundation.
On some level, you already know this, so when you come into work in the morning, exhausted, you reach for…yep, more coffee. Not ideal.
So, what’s a coffee lover to do with these conflicting messages of benefits and consequences?
Drink no more coffee than feels right for you — and if you sense that you’re a slow metabolizer, be smart about when and how much coffee you consume. Your body will thank you.