Pros and Cons of the Caffeine Craze
Caffeine drinks are trendy, but are there some downsides? WebMD gets the perspective of experts.
By Kathleen Doheny
Reviewed by Louise Chang, MD
If you crave caffeine to get you through the day, you're not alone. About 68% of Americans say they're hooked on coffee this year, compared with 64% last year, according to the National Coffee Association.
Sales of caffeine-laced energy drinks such as Red Bull and Monster are expected to rise 60% this year, says Gary Hemphill of the Beverage Marketing Corporation, a consulting firm in New York.
If those don't give you enough of a buzz, you can turn to sodas, coffee-flavored yogurt -- some of it has as much caffeine as a 12-ounce soda -- coffee ice cream, chocolate candy, or iced tea.
And one new product, controversially named Cocaine, goes one step further, offering a mega-dose of caffeine that dwarfs its nearest competitors.
Some medicines and dietary supplements for weight loss also include a dose of caffeine. Coke is even planning to roll out a new "negative calorie" carbonated green tea beverage this fall called Enviga that combines caffeine with other ingredients to -- according to the company -- increase calorie burning.
So what's the harm, ask caffeine fans, who point to studies showing the benefits of caffeine, such as boosting memory and improving concentration and perhaps lowering risks of diseases such as Alzheimer's and liver cancer.
But others are alarmed by what they say is an increasingly overcaffeinated nation; they are concerned by studies finding too much caffeine can set you up for high blood pressure, high blood sugar, and decreased bone density -- not to mention jangled nerves.
Caffeine abuse by young people alarms some experts. It was the cause of many calls to an Illinois Poison Center over a three-year tracking period, a team of doctors reported at the American College of Emergency Physicians annual meeting in New Orleans.
How Caffeine Works
"Caffeine exaggerates the stress response," says James D. Lane, PhD, professor of medical psychology at Duke University Medical Center in Durham, N.C., and a long-time caffeine researcher. "At the cellular level, caffeine locks the receptor normally used by adenosine, a brain modulator that provides feedback to avoid overstimulation of nerve cells. If adenosine is locked up, nothing keeps the nervous system from getting too excited at a cellular level."
People joke about being hooked on caffeine, but is it truly addictive? Researchers have debated that question for years.
"There's no question," says Roland R. Griffiths, PhD, professor in the departments of psychiatry and neuroscience at Johns Hopkins University School of Medicine in Baltimore and a veteran researcher in the area. Caffeine is addictive for some people, he says. "Caffeine does produce dependence, and caffeine withdrawal is a real syndrome."
But George Koob, PhD, professor of the Committee on the Neurobiology of Addictive Disorders at The Scripps Research Institute, San Diego, disagrees. "While it is possible to be addicted, most people are not," he says. "I think most of my colleagues would agree."
The Benefits of Caffeine
Caffeine can improve memory, decrease fatigue, improve your mental functioning, study after study suggests.
It can improve your short-term memory and speed up your reaction times, according to a study presented in 2005 at the Radiological Society of North America.
Moderate coffee consumption -- defined as three or four cups a day, providing 300 or 400 milligrams of caffeine -- carries "little evidence of health risks and some evidence of health benefits," conclude researchers from the Linus Pauling Institute at Oregon State University in Corvalis, writing in Critical Reviews in Food Science and Nutrition in March 2006.
Coffee drinking, the researchers say, may help prevent type 2 diabetes, Parkinson's disease, and liver disease, including liver cancer. And it doesn't appear to significantly increase heart disease risk or cancer. But, they warn, those with high blood pressure, as well as children, teens, and the elderly, may be more vulnerable to caffeine's adverse effects.
The Downsides of Caffeine
Caffeine does boost blood pressure, Lane and others have found. Although the rise is temporary, Lane questions whether it's good for you when it occurs over and over. After much research, he has concluded that repeated elevations in blood pressure and increases in your reactions to daily stress that occur with caffeine intake could boost the risk of heart disease. He worries, too, about the boost in blood glucose levels that accompanies caffeine intake.