People who love coffee consider it more than just a drink. It's part ritual, part pick-me-up, part habit.
"It sort of gives me a lift," says long-long-longtime coffee drinker Rich Warwinsky. "And if I manage it well and drink it two or three times a day, half and half, I'm not too crazed."
With this description, it sounds as if Warwinsky is referring to a drug habit. And in fact, he is.
"Caffeine is a drug that can affect our central nervous system and affect some pretty important areas of our lives," says American University caffeine researcher Laura Juliano.
And it's a drug with pros and cons. Caffeine can help put us in a good mood in the morning or help us focus on a task at hand. But it can also make us anxious and interfere with sleep. Juliano is trying to figure out exactly how much she can tolerate. She drinks a little bit of caffeine from coffee first thing in the morning. During a late-morning break at a campus cafe, she ordered decaf.
"Even having it now may have an effect on my being able to fall asleep tonight," she says. "There's research to show that people who have caffeine in the morning can take longer to fall asleep that evening."
Sensitivity to caffeine varies widely from one person to the next. Researchers believe part of the equation is genetic makeup, part is body weight. Also, eating a meal just before consuming caffeine can slow down the stimulant's effect. Smokers can often tolerate more caffeine because nicotine is thought to stimulate the enzymes that break caffeine down.
Juliano says age is another factor.
"People become more sensitve to caffeine as they get older. We require liver enzymes to break down caffeine. And as one ages, there are just changes in our metabolism."
As a general rule of thumb, most caffeine users need a surprisingly small amount of the stimulant to enjoy its pleasant effects. Studies show that 100 milligrams -- just a 6-ounce cup of a typical automatic-drip coffee -- produces a lift.
"People report increased well-being, better mood," Juliano says. "They become more sociable and talkative."
But a higher dose can cause problems.
"Above 200 milligrams -- and certainly by 400 milligrams -- many people report anxious, jittery feelings of uneasiness," Juliano says.
Keeping your daily dose of caffeine under 400 milligrams can be tricky because it's hard to know how much caffeine is in any given cup of coffee or tea.
One study published in the Journal of Analytical Toxicology by researcher Bruce A. Goldberger of the University of Florida College of Medicine shed light on the variability of caffeine content. His research found that 16 ounces of caffeinated coffee from Starbucks had 100 milligrams more of caffeine than the same serving size from Dunkin' Donuts. The study also found that Starbucks' caffeinated breakfast blend, purchased at a Florida store, varied greatly in its caffeine content from day to day. One day, a 16-ounce cup had 259 milligrams of caffeine. Another day, the same size coffee contained 564 milligrams.
Tea offers a much gentler lift. A cup generally contains from 30 to 90 milligrams of caffeine, depending on the variety and how long the bag is steeped. Sodas typically have the least caffeine. A 12-ounce Diet Pepsi, for example, has 36 milligrams.
When people ask Juliano about how to manage their caffeine intake from coffee, she sometimes turns them on to espresso drinks.
Let's say you order a cappuccino, which is made with espresso. "You're actually getting far less caffeine than if you were to get a drip coffee," Juliano says.
"People often think, 'Oh, I had espresso and I really had a jolt.' But in actuality, it could be a better amount [of caffeine] to consume because you're keeping it under 100 milligrams a day, and that's what we recommend, in terms of getting a little boost."
The challenge of our caffeinated society, where eight in 10 adults report consuming caffeine, is that many people fall into dependency without realizing it. What starts as one cappuccino a day can escalate. When this happens, Juliano says, it's not terribly alarming. Compared to classic drugs of dependence, caffeine is considered safe. But there is a downside, which becomes apparent when you skip a day and go into withdrawal.
"The No. 1 symptom you hear people say... is 'Oh, I get this pounding headache,'" Juliano says.
If a caffeine-dependent coffee lover doesn't want a morning pick-me-up on the weekend, cutting back to half a cup is one solution. That little bit of caffeine "may prevent withdrawal," she says.
Then again, you could just break the caffeine habit altogether. If you go cold turkey, research shows that the headaches will last anywhere from a few days to several weeks. Juliano says the other option is to break the caffeine habit over a week or two. That's what she plans to do ... one day soon.
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In your health today, how to be a savvy caffeine consumer, and also a look at why, despite lattes and espressos, adults don't have as much energy as kids.
First, caffeine. Experts say a small amount of the stimulant can give many people the lift they want without producing the anxious jitters. NPR's Allison Aubrey looks at how experts calculate how much is too much.
ALLISON AUBREY: People who love coffee say it's more than just a drink. The morning cup is part ritual, part pick-me-up. At Washington coffee shop, Rich Warwinsky enjoys his.
Mr. RICH WARWINSKY (Coffee Drinker): It's a habit. It's a little bit of a jones. It sort of gives me a lift. And if I'm manage it well, I drink two or three times a day, half and half, and I'm not too crazed.
AUBREY: Not too crazed when he manages it well. If that description sounds like he could be talking about a drug - but caffeine, a drug? Absolutely, says researcher Laura Juliano, who's taking a break at a coffee shop near her lab.
Ms. LAURA JULIANO (Researcher, American University): Caffeine is a drug that can affect our central nervous system and have effects on some pretty important areas of our lives.
AUBREY: Juliano runs a caffeine research lab at American University. She says after years of an on-again/off-again relationship with caffeine, she's still trying to figure out exactly how much she can personally tolerate.
Ms. JULIANO: Can I order a decaf?
Unidentified Woman: Sure.
Ms. JULIANO: I'll have a small decaf, please.
AUBREY: Juliano says she's already had a small amount of regular coffee at home, so she's laying off.
Ms. JULIANO: Even having it now may have an effect on me being able to fall asleep tonight.
AUBREY: Even though it's only 10 o'clock in the morning, though?
Ms. JULIANO: Yeah, sure. There's actually research showing that people who have caffeine in the morning can have a longer latency to fall asleep that evening.
AUBREY: Sensitivity to caffeine varies widely from person to person. Part of the equation is genetic makeup, part is body weight, and a meal can blunt or slow down the stimulant's effect. Smokers can often tolerate more caffeine because nicotine is thought to stimulate the enzymes that break caffeine down. Juliano says another factor is age.
Ms. JULIANO: We require liver enzymes to break down caffeine. And as one ages, there's just changes in our metabolism.
AUBREY: All these factors help explain individual differences, and how they can change over time. But Juliano says as a general rule of thumb, most caffeine users who enjoy the pleasant effects of the stimulant need surprisingly little. Studies show that 100 milligrams, which is just six ounces of a typical automatic drip coffee, produces a lift.
Ms. JULIANO: People report increased well-being, better mood. They become more sociable and talkative.
AUBREY: But it's not all good.
Ms. JULIANO: As that dose increases - let's say above 200 milligrams, certainly by about 400 milligrams - many people report anxious, jittery feelings of uneasiness.
AUBREY: Staying under 400 milligrams can be tricky, mainly because it's hard to know how much caffeine is in any given cup of coffee or tea. One published study of Starbucks coffee found the caffeine content in one of its drinks can vary from 250 milligrams to as high as 560 milligrams. Teas generally have about one third as much caffeine as coffees, but they range too, depending on how long the bag is steeped. A Diet Pepsi has just 35 milligrams.
When people ask Juliano about choosing a coffee, she sometimes turns them on to a espresso drinks.
Ms. JULIANO: Let's say you order a cappuccino and it's made with one shot of espresso. You're actually getting far less caffeine in that drink than you would be if you just ordered, let's say, a drip coffee.
AUBREY: Juliano says this always seems to surprise caffeine drinkers.
Ms. JULIANO: People often think, oh, espresso - you know, I had some espresso and that really gave me jolt. But in actuality that could be a better amount of caffeine, actually, to consume, because you're keeping the level under 100 milligrams a day. And that's what we recommended in terms of trying to use caffeine to get a little boost but not using so much that you are dependent on it and you need it every day.
AUBREY: The challenge of our caffeinated society, where eight in ten adults report using caffeine, is that many people fall into dependency without realizing it. What starts as one cappuccino a day escalates. When this happens, Juliano says, it's not terribly alarming. Caffeine is considered safe relative to classic drugs of dependence. But the downside becomes apparent when you skip a day and go into withdraw.
Ms. JULIANO: The number one symptom you hear people say is, oh, I get this pounding headache.
AUBREY: So for the caffeine dependent it's an every day habit. On weekend days, when people don't want the morning pick-me-up, Juliano says cutting back to just a half a cup may work.
Ms. JULIANO: You don't have to have the same amount of caffeine every day. But if you had at least a little bit, it may prevent withdrawal.
AUBREY: If you go cold turkey, research shows the headaches will last anywhere from a few days to several weeks. Juliano says the other option is to just break the caffeine habit. This is what she plans to do, one day soon.
As for longtime coffee drinker Rich Warwinsky, who's finishing his morning joe...
Mr. WARWINSKY: It's probably better not to have it.
AUBREY: But for now you're sticking with it?
Mr. WARWINSKY: Absolutely.
AUBREY: Allison Aubrey, NPR News, Washington. Transcript provided by NPR, Copyright NPR.