Depending on how you use it, coffee can be a pick-me-up or a real downer.
Coffee's caffeine jolt can temporarily boost alertness, perk up performance, and possibly even improve concentration.
But before you pour yourself another cup of joe, experts say it's important to remember coffee's main ingredient, caffeine, is a drug and not a nutrient required for good health like vitamins and minerals. And as with any drug, there are right ways and wrong ways to use it.
"The right way is to know how it affects your body and your reasoning," says registered dietitian and epidemiologist Gail Frank. "The wrong way is to use it in an abusive way, and that means going without sleep and then drinking a lot of coffee to get the perk."
"The other wrong way, as a parent, is to allow young children to use it and have it as crutch -- not only for the perk but because it may also displace nutrient-rich beverages for kids," says Frank, who is professor of nutrition at California State University at Long Beach.
Frank says the caffeine in coffee is especially dangerous for young children and teenagers with growing bones because caffeine leaches much-needed calcium from the bones and may retard growth or make the bones weaker.
Five milligrams of calcium is lost for every six ounces of coffee that is consumed, says Frank. But the good news is you can put back some of those lost nutrients by adding two tablespoons of milk to your coffee or making your espresso a latte.