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Coffee is Good For Your Brain and Won’t Dehydrate You


Today is National Coffee Day in the U.S.*, and what better way to celebrate than to dig into the science of how coffee affects brain health?

Coffee has a mixed role in the public consciousness. Depending on who you talk to, coffee can be an unhealthy vice, a necessary quick fix for staying awake, or the next miracle health supplement. The truth, as usual, is somewhere in the middle.

One review of the literature concluded that the benefits generally outweigh the risks. When it comes to cognitive performance, the caffeine in coffee blocks the annoying neurotransmitters that slow down brain activity, ultimately making you temporarily sharper. And as we’ve discussed before, there is some evidence that coffee helps prevent long-term cognitive decline too.

It’s a myth that coffee causes dehydration. It has a mild diuretic effect (it makes you pee), but that’s balanced by the fact that it’s mostly water. For most people, if you regularly drink a moderate amount of coffee—between 38 and 400mg of caffeine, or 0.3 to 4 cups of brewed coffee—the brain benefits outweigh any risk of dehydration. Hopefully that makes you feel good about celebrating Coffee Day with an extra cup of joe.

* You don’t have to wait long if you’re outside the U.S.—apparently International Coffee Day is on October 1st, and it’s even acceptable to celebrate all weekend if you so choose.

This post was written by Mike Battista, a staff scientist from Cambridge Brain Sciences.