How Much Coffee Is Too Much?
Whether it's served in a demitasse mug or a venti mochachino bucket, coffee is an essential, eye-opening morning ritual for many of us. But at what point does throwing back another vente doing you more harm than good? As you probably know, coffee's main health concern—its caffeine content—is also why you drink so much of it. So what exactly is caffeine doing to your body, and how much of it can you safely handle?
What is caffeine?
Caffeine is a naturally-occurring crystalline alkaloid derived from the leaves, seeds, and fruit of a number plants including the coffee tree and tea bush, as well as less common yerba maté and guarana berries. Plants produce the compound as both a natural insecticide against harmful bugs and as a reward for pollinators.In humans, however, it acts as a neurostimulant and mild psychoactive, invoking a temporary state of alertness and focus. In fact, caffeine is the world's most widely consumed psychoactive drug, and can be found in everything from coffee and tea to energy drinks and chocolate. Altogether, some 90 percent of adults in North America consume caffeine daily in one form or another. "It helps people stay alert and stay focused," Lisa Casas, R.D., L.D., a clinical dietitian at University of Iowa Hospitals and Clinics, told the University's blog. However, caffeine's boost is transient at best. "It really doesn't stay in the system very long—it's only about two to three hours before it is excreted from the body," Casas continued.
How much caffeine is in coffee?
Coffee can contain anywhere from 60 to 120 mg per 8-ounce serving, depending on how it is brewed. Teas contain far less, averaging 20 to 90 mg per 8-ounce cup, as do soft drinks, which pack around 20 to 40 mg per can. Even chocolate contains a small amount of caffeine, about 6 mg per ounce.
Energy drinks, on the other hand, contain far more caffeine than any of those potables. A standard 1.93 oz dose of 5 Hour Energy holds a whopping 207 mg, according to a 2010 Consumer Reports study. Similarly, Monster Energy drinks pack around 160 mg per 16 oz can, though the 24 oz MegaMonster variant contains 240 mg. Red Bull contains an equal proportion of caffeine as MegaMonsters (80 mg per 8 0z), though they're a quarter of the serving size.
However, all of these drinks pale in comparison to the 5150 Semi Sweet energy shot. Each 1 ounce dose of 5150 delivers a heart-bursting 475 mg of caffeine—that's 2.6 times the amount of stimulant you'd get from downing an 8-ounce Starbucks brew.
So how many cups are we talking?
While some studies have suggested links between caffeine consumption and lower blood pressure, a recent investigation published in Mayo Clinic Proceedings found that a study's participants under the age of 55 who consumed more than 28 cups of coffee a week—four cups a day—had a much higher mortality rate than those who drank fewer than that. The Mayo team examined data from the Aerobics Center Longitudinal Study, a two decade long survey of the lifestyle habits of nearly 45,000 people, ages 20 to 87, between 1979 and 1998.