The Buzz on Caffeine

It's hard to find much wrong with a drug that can battle fatigue and improve creativity and could even help prevent Parkinson's disease and diabetes. It's also hard to find much right with a drug that elevates blood pressure, aggravates stress, causes insomnia and leads to addiction. When both drugs are the same thing, it's hard to know what to think.

That's the rap--and the rep--associated with caffeine, the recreational chemical of choice for nearly 60% of Americans. But what of the received wisdom is true? Is caffeine a scourge, a tonic, a little bit of both?

One thing's for certain: we sure love the stuff. There are 167 million coffee drinkers in the U.S., and they consumed nearly 6.3 billion gal. last year alone. The average drinker admits to 3.4 cups a day, although the National Coffee Association is studiously vague about what constitutes a cup--deliberately, perhaps, in an era in which a large Starbucks sloshes in at a whopping 20 oz. On top of our coffee, we poured down 2.4 billion gal. of tea in 2003, not all of which was gentle herbals. Biggest of all are carbonated soft drinks, 70% of which are caffeinated. Americans consumed a stunning 15.3 billion gal. in 2003, or 574 cans for every man, woman and child.

The good news is that not only does all that caffeine not necessarily hurt but in some ways it may help. Java's famous energy jolt is no illusion, improving performance on tasks and helping people stay alert. That, however, requires drinking caffeine the right way, and most people don't, loading up first thing in the morning and then crashing by the afternoon, when the chemical--with a half-life of up to six hours--is leaving the system.

Better, says sleep researcher James Wyatt of Rush University Medical Center in Chicago, to consume a little caffeine in the morning and continue to take it in very small doses throughout the day. That should evenly block the uptake of adenosine, a neurotransmitter-like chemical that helps trigger sleep. In a recent study, Wyatt and others tested that theory, comparing a group of volunteers taking low, steady caffeine doses with subjects who got none at all. The caffeinated group indeed performed better on cognitive tests, with no late-day crash. (Though p.m. caffeine may not do much for your ability to sleep when you want to.)

In another area of study entirely, some research suggests that caffeine may help prevent Parkinson's disease and Type 2 diabetes. Using data gathered in an 18-year health survey of 125,000 men and women, Meir Stampfer, professor of nutrition and epidemiology at the Harvard School of Public Health, found that coffee drinkers had lower incidences of both diseases, though the benefit was a bit less pronounced for Parkinson's. He concedes that the work is preliminary, particularly in light of other studies that show caffeine worsens diabetes in people who already have it. But he is convinced that further studies of possible therapeutic effects may lead to treatments. "Our findings point to more research," he says, "[to] figure out why caffeine is working this way."