Coffee and fruit juice are a surprisingly good combination. Espresso and orange juice, iced coffee and watermelon juice, coffee with coconut water and lime, almost every signature drink in the national and world rounds of the Barista Championship, the combinations are endless and endlessly delicious. But another combination of fruit and coffee may have an additional benefit beyond taste. Drinking grapefruit juice with coffee may prolong the effects of caffeine.
As reported Food and winethe interaction may be similar to the effect of grapefruit juice on drugs such as selective serotonin reuptake inhibitors (SSRIs). Grapefruits contain hundreds of chemicals, and at least one – though it’s unclear which one – binds to enzymes in the digestive tract, causing SSRIs to be absorbed more slowly.
Likewise, grapefruit juice is thought to snail-paced the absorption of caffeine. In particular, it blocks the enzyme CYP1A2, which is responsible for the breakdown of caffeine. After blocking this enzyme, caffeine metabolizes more slowly, so it can stay in the body longer.
The exact effect of grapefruit juice on absorption is a matter of debate. According to F&W, a 1993 study found that grapefruit juice caused a “miniature but significant reduction in oral caffeine clearance.” However, a 1996 study came to the contradictory conclusion that “a normal-sized glass of grapefruit juice does not appreciably alter caffeine metabolism.”
It is possible that the effect will vary because the individual response to caffeine itself is variable. Still, for those looking to get the most out of their caffeine intake without having to boost it, there may be something juicy about this coffee that’s worth exploring. Plus, summer is coming and espresso and grapefruit juice with a nice splash of tonic sound like it hits challenging on a warm day.
