Coffee and fruit juice make a surprisingly good pairing. Espresso and orange juice, iced coffee and watermelon juice, coffee with coconut water and lime, just about every signature beverage in the national and world rounds of the Barista Championship, the combinations are endless and endlessly delicious. But another fruit and coffee combo may have an added benefit beyond flavor. Drinking grapefruit juice with coffee may prolong the caffeine buzz.
As reported by Food & Wine, the interaction may work similarly to how grapefruit juice affects medications like Selective Serotonin Reuptake Inhibitors (SSRIs). Grapefruits contains hundreds of chemical compounds and at least one—though it isn’t clear which—binds to enzymes in the intestinal tract, resulting in a slower absorption of SSRIs.
Similarly, grapefruit juice is believed to slow the absorption of caffeine. In particular, it blocks the CYP1A2 enzyme, which is responsible for breaking down caffeine. With that enzyme blocked, caffeine metabolizes more slowly, allowing it to hang out in the body longer.
The exact amount grapefruit juice affects absorption is up for debate. Per F&W, a 1993 study found that grapefruit juice resulted in “a small but significant decrease in oral caffeine clearance.” But a 1996 study came to a contradictory conclusion, that “a normal-sized glass of grapefruit juice does not appreciably alter caffeine metabolism.”
It may be the case that the effect varies, because the individual response to caffeine is itself variable. Still, for those looking to get the most out of their caffeine intake without having to increase it, maybe this has some juice and is worth exploring. Also, it’s about to be summer and espresso and grapefruit juice with a splash of some nice tonic sounds like it would hit pretty hard on a blisteringly hot day.
Zac Cadwalader is the managing editor at Sprudge Media Network and a staff writer based in Dallas. Read more Zac Cadwalader on Sprudge.
