You could drink more coffee than average if you have these special bits of DNA

Each day, the average American drinks about 300 milligrams (mg) of caffeine.

That's the amount of caffeine you'll find in about three cups of coffee.

But some people can drink more than that without feeling as jittery.

If you get a genetic test, like from 23andMe, you can find out if your genes give you this magical ability (or curse, depending on how you look at it).

The test shows you four particular gene variants that studieshaveshown are responsible for regulating caffeine in the body.

Here's what the results of a 23andMe test tell you about these caffeine genes.

First, some facts about caffeine. A cup of coffee has about 95 mg, while a cup of tea has 47 mg, and a bottle of soda has 44 mg.

Caffeine keeps you alert by blocking a sleep-inducing molecule in your brain. But your body eventually breaks down the caffeine with enzymes produced by the liver.

Source: Tech Insider

One of those enzymes is called CYP1A2, and it's encoded by the CYP1A2 gene.