Why Some People Drink More Coffee—It’s in Their Genes

If you’ve ever wondered why some friends can chug multiple espressos without blinking while one cup leaves you jittery, science may have part of the answer—and it’s not just habit or willpower. A major study suggests your DNA plays a real role in how much coffee you crave.

According to researchers at the Erasmus University Medical Center in the Netherlands, who studied over 18,000 people, your tendency to drink more coffee is linked to specific genes that affect how quickly your body processes caffeine. Two key genes, CYPIA1 and NRCAM, were found to influence both coffee intake and caffeine tolerance.

How Your Body Breaks Down Caffeine

Caffeine isn’t just sitting in your system doing nothing—it’s being actively broken down, mostly in the liver. This process relies on certain enzymes, which are proteins that help chemically transform substances in your body. The speed and efficiency of these enzymes determine how long caffeine stays active and how intense its effects feel.

The Role of Liver Enzymes and Genes

Different people produce varying levels of these caffeine-metabolizing enzymes. That variation is tied to your genetic code. The Dutch study identified that the genes responsible for producing these enzymes include CYPIA1 and NRCAM. These genes don’t just affect enzyme production—they also correlate with how much coffee individuals tend to consume on a regular basis.

What the Study Found

In their survey of 18,000 participants, researchers observed that those with more active forms of the CYPIA1 and NRCAM genes were more likely to drink greater amounts of coffee. Importantly, these same individuals reported fewer negative effects even when consuming larger quantities of caffeine. The findings were published in the May 5 issue of the UK journal Molecular Psychiatry.

Why This Matters for Coffee Drinkers

This research helps explain why caffeine affects people so differently. It’s not merely about personal preference or acquired tolerance—it’s also hardwired into your biology. Your genetic makeup influences how quickly your liver breaks down caffeine, which in turn shapes how much coffee you’re comfortable drinking and how you experience its effects.

Frequently Asked Questions

What genes are linked to coffee consumption?

The study identified the genes CYPIA1 and NRCAM as being associated with both the amount of coffee people drink and their tolerance to caffeine. These genes influence the production of liver enzymes that break down caffeine.

Does genetics determine how much coffee I can drink?

Yes, to an extent. Genetic variations affecting liver enzymes—particularly those governed by the CYPIA1 and NRCAM genes—can influence how quickly your body metabolizes caffeine, which impacts how much coffee you’re likely to consume and how you feel after drinking it.

Why do some people feel fine after several coffees while others get jittery?

This difference is partly due to genetic factors that affect how efficiently your liver enzymes process caffeine. People with more active caffeine-metabolizing genes often tolerate higher amounts of coffee with fewer side effects.

How was the coffee and genetics study conducted?

Researchers at Erasmus University Medical Center in the Netherlands analyzed data from 18,000 participants. They looked at genetic markers, coffee consumption habits, and self-reported responses to caffeine to identify links between specific genes and coffee intake.

Where can I read the original coffee genetics study?

The study was published in the British journal Molecular Psychiatry on May 5. It details the genetic analysis of over 18,000 individuals and the identified links between the CYPIA1 and NRCAM genes and coffee consumption patterns.

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