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Here's a shocking statistic—90% of Americans need a drug just to get through the day. If they don't get it, many suffer withdrawal symptoms. That may sound like an exaggeration, but think about the caffeine that nearly all American adults get in their coffee, tea and soda each day. Caffeine is a drug—and a potent one.
It is true that caffeine increases energy and alertness—and may even help fight certain chronic diseases (see next column). In large amounts, however, caffeine can lead to nervousness and agitation—along with high blood pressure, rapid heartbeats and even panic attacks.
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- A Cup of Decaf May Prevent Memory Loss
- Coffee Helps Prevent Constipation After Surgery
- Coffee Combats Parkinson’s Disease
- Coffee Helps Migraines
- Coffee Protects Against Liver Cancer
- Best and Worst Drinks for Preventing Kidney Stones
The facts about caffeine…
IT'S EVERYWHERE!
With caffeine now included in so many different beverages and foods, it's easy to consume much more than you realize.
Do the math: The average US adult drinks about three cups of coffee a day, with anywhere from 75 mg to 200 mg of caffeine in an eight-ounce cup (decaf has about 12 mg or less per cup).
Tea drinkers get 67 mg in an eight-ounce cup of generic black tea brewed for three minutes and 43 mg from the same size generic green tea with an equal brewing time (the caffeine content increases the longer it's brewed).
And do you have a soft drink now and then? A Coke or Pepsi (regular or diet) has about 35 mg of caffeine per 12-ounce serving. Some energy drinks have more than double that amount.
The dark chocolate you may enjoy—in part for its health benefits—has about 20 mg per ounce (the darker the chocolate, the more caffeine it will contain).
Meanwhile, the Excedrin that you may take for headaches adds another 65 mg per tablet.
What you may not realize: The FDA advises getting no more than 400 mg of caffeine a day, but you could be getting a lot more than that.
HOW CAFFEINE HELPS
An increasing body of evidence shows that caffeine—whether it's from coffee, tea, colas or some other source—has positive health effects. Key examples…
• Less cognitive decline. In a 2012 study, 124 participants with mild cognitive impairment (which often precedes Alzheimer's disease) had memory tests at the start of the study and again two to four years later. Those who had caffeine levels consistent with three daily cups of coffee did not develop Alzheimer's, while those who developed dementia had caffeine levels that were, on average, 51% lower.
The study did not prove that caffeine is protective. Coffee, for example, contains other chemical compounds that might protect brain cells. But it's possible that the increased alertness from caffeine could make people more likely to pursue social and intellectual activities that improve brain health.
• Fewer gallstones. Two important studies found that coffee drinkers were less likely to develop gallstones (20% less likely in women and 40% in men) than people who don't drink coffee. The reason is not yet known, but it's possible that gallbladder contractions triggered by caffeine reduce buildups of stone-forming cholesterol and bile pigments. Drinkers of decaf didn't get the same benefit.
• Less Parkinson's disease. Caffeine intake has been linked to lower incidence of Parkinson's disease, and recent research found that symptoms, such as tremors and stiffness, eased in people with Parkinson's who consumed 100 mg to 200 mg of caffeine twice a day (roughly two to four cups of coffee).
• Headache relief. A strong cup of coffee or tea can help ward off a migraine by constricting blood vessels in the brain. Caffeine also offsets the widening of blood vessels that occurs during migraines. Not surprisingly, you'll see caffeine listed on the labels of painkillers, including not only Excedrin but also Anacin and Midol.
• Better workouts. Caffeine helps mobilize fatty acids for endurance, so it could improve a workout. But be sure to drink water before, during and after exercise because caffeine can cause dehydration.
THE NOT-SO-GOOD NEWS
Even though it's almost impossible for an adult to overdose on coffee, tea or other beverages with caffeine, the FDA has warned consumers to avoid any powdered form of caffeine sold on the Internet. One teaspoon of the powder, which was recently linked to the death of a teenager, contained the equivalent of 25 cups of coffee.
You probably know that even "safe" amounts of caffeine, such as that found in a few cups of coffee, can lead to sleep problems (especially when consumed within six hours of bedtime) and can cause unpleasant effects, such as jitteriness, in some people. Caffeine also may increase risk for…
• High blood pressure. Caffeine from a cup or two of coffee can temporarily increase the heart rate by as much as 10 to 20 beats per minute in sensitive individuals. This isn't a problem in healthy adults but could be dangerous for those with hypertension. An increased heart rate also can trigger heartbeat irregularities (arrhythmias) in some people.
• Impaired glucose regulation. Some studies have found that people with type 2 diabetes who consume two to three cups of coffee may have higher-than-expected surges in glucose (blood sugar) after meals. People with diabetes should talk to their doctors about their use of caffeine, especially if they are having trouble regulating blood glucose.
But just to show you how complicated caffeine research can be, a recent study found that coffee consumption reduced risk for type 2 diabetes. Is it the caffeine or something else in the coffee? Research is ongoing.
• Stress. Caffeine increases adrenaline, a hormone that's already elevated during times of stress. The effect can be magnified if you happen to drink even more coffee during stressful times.
There's some evidence that caffeine also can trigger panic attacks in people who have had them previously. Even if you don't have a history of panic attacks, large amounts of caffeine (more than 300 mg, or about three cups of coffee) at one time can trigger them.
• Incontinence. Caffeine increases urine production, and studies have linked coffee intake to urinary incontinence.
Takeaway for everyone: To minimize your risk for caffeine-related health problems, consider spreading your coffee intake out over several hours or alternate it with decaf or water.
HOW BIG A BUZZ?
Americans get most of their caffeine from coffee, but it's tricky to predict how much you'll actually get. The exact amount depends on the coffee variety, how it's roasted and even how it's prepared. Some surprising facts…
• The inexpensive bulk coffees in supermarkets, made from robusta beans, can have double the caffeine of the more expensive arabica beans (used in specialty coffees from Costa Rica and Sumatra, for example).
• Dark-roasted coffees have a strong taste but actually have less caffeine than lighter varieties.
• Drip coffee has more caffeine than percolated or coffee made with a French press. A "cup" of espresso has about the same amount of caffeine as a cup of percolated coffee, but the espresso cup is only about two ounces. The higher concentration causes the caffeine to be absorbed more quickly, giving an "espresso buzz."
Source: Wilkie A. Wilson, Jr., PhD, a neuropharmacologist and research professor of prevention science at the Social Science Research Institute at Duke University, where he is also a faculty fellow at the Center for Child and Family Policy, both in Durham, North Carolina. Dr. Wilson is coauthor, with Cynthia Kuhn, PhD, and Scott Swartzwelder, PhD, of Buzzed: The Straight Facts About the Most Used and Abused Drugs from Alcohol to Ecstasy (Norton).
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