What you should know about caffeine

For most people, caffeine in moderation is safe, experts say; some caffeine sources, like coffee, may have health perks.

Story highlights

  • Energy shots and drinks have come under fire after reports of deaths
  • People can become accustomed to high amounts of caffeine over time, experts say
  • Caffeine amounts are not currently required to be listed on food labels
  • Research has shown healthy consequences from coffee consumption
Last week, 5-hour Energy came under fire after the New York Times reported the Food and Drug Administration received 13 reports of deaths possibly linked to the energy drink. The claims add to the five deaths reported to the agency linked to Monster Energy, raising concerns about the safety of the beverages.
How could the energy drinks, whose main ingredient is caffeine, be connected to the deaths? Andrea Giancoli, a registered dietitian and spokesperson for the Academy of Nutrition and Dietetics, and Michael Jacobson, executive director of the Center for Science in the Public Interest, answer some questions worried consumers are asking about the beverages.
How does the body respond to caffeine?
"It's a stimulant. It wakes you up. It makes you more alert. It is stimulating your nervous system," says Giancoli. Giving the nervous system a jolt can lessen fatigue and sometimes improve mood. As heart rates go up, the body circulates more blood and can speed up the metabolism.
What are some of the adverse effects of caffeine?
If you're not used to the amount of caffeine you're consuming, you can feel jittery. "You can get heart palpitations and feel agitated and nervous and like you're bouncing off the walls," says Giancoli. "You can feel your heart pounding very quickly, and your blood pressure goes up. Imagine if your body were undergoing this, times 10. It would land you in the emergency room. Your heart can only handle so much, and you are probably going to pass out."
How much caffeine is too much?
"Typically we would say 300 to 500 mg is safe for most people — not that people need that much or want that much — it's about three to five cups of coffee," says Giancoli. "There are people who can drink much more than that. Some people can drink a whole pot of coffee a day and have no problem. Then you hear about people who cannot retain caffeine at all and have one cup, and they're flying off the walls."
Giancoli says people can become accustomed to high amounts of caffeine over time, so the effect in enhancing alertness and improving energy may dwindle in heavy and frequent consumers compared with those who rarely drink caffeinated beverages.
Why are the amounts of caffeine in energy drinks unlabeled?
The FDA currently does not require caffeine amounts to be listed on food labels. Caffeine is not considered a nutrient and therefore only needs to be listed as an ingredient. The FDA does not regulate energy drinks because they are sold as dietary supplements. If the FDA did regulate them, most would have levels of caffeine higher than what the agency deems safe.
The agency currently allows sodas to contain 71 mg of caffeine per 355 ml. According to the FDA, energy drinks contain from 160 to 500 mg of caffeine per serving. A recent Consumer Reports test of 27 best-selling energy drinks found that 11 do not list caffeine content, and among those that do, the tested amount was on average 20% higher than what's listed.
Is it possible to die from caffeine?
Overdoing caffeine alone is actually pretty difficult to do, says Jacobson. "It's highly unlikely. Someone would really have to make an effort to consume 40 or so 200-mg caffeine tablets."
Is it only the caffeine found in energy drinks that are the main concern, or are other ingredients playing a role?
"There just hasn't been enough studies done on the other ingredients," says Giancoli. "The problem comes when there is a massive amount of caffeine. Some of these drinks are very concentrated with caffeine for a very small amount of liquid. It would be easy to drink many of these in a row." She says some teenagers drink a large amount of high-energy beverages to get a buzz and also mix the drinks with alcohol.
"It's the excessive intake that we are concerned about," says Giancoli. "There is a part of the population that h