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The truth about caffeine

ERIC DEGGANS, HOST:

Caffeine is the most widely consumed drug in the world. Here in the U.S., according to a 2022 survey, more than 93% of adults consume caffeine, and of those, 75% consume caffeine at least once a day. So why do so many people feel the need to cut back? Is all that morning Joe something to worry about? Life Kit's Andee Tagle has more on the effects of caffeine - plus, tips for making sure your relationship with everyone's favorite psychostimulant is a healthy one.

ANDEE TAGLE, BYLINE: Caffeine gets a bad rap. You've heard the whispers. Caffeine stunts your growth, causes heart disease or dehydrates you. But these rumors just don't ring true for the vast majority of us. Caffeine's real problem seems to be a bad case of guilt by association.

MARILYN CORNELIS: Consuming a lot of caffeine is often equated with someone who's really stressed out and working hard. And some of those other behaviors are actually more greater risk factors for health. And so it becomes what we call a confounder in some of this research.

TAGLE: That's Marilyn Cornelis, an associate professor of preventive medicine and nutrition at Northwestern University's Feinberg School of Medicine.

CORNELIS: Someone who's drinking a lot of caffeine might be short on sleep. We know sleep is an important risk factor for a number of diseases.

TAGLE: Nicotine is another great example. Smoking and coffee consumption are highly correlated.

CORNELIS: A smoker will want to consume more coffee in order to get that psychostimulant effect. And we know that smoking is a risk factor for a number of health outcomes and diseases.

TAGLE: Another important thing to note here - Dr. Ugonna Iroku a gastroenterologist in New York City, reminds us not all caffeinated drinks are created equal. A black coffee or green tea offer antioxidants and a slew of other potential benefits, for example. But syrupy frappuccinos, sodas, energy drinks...

UGONNA IROKU: Do you have a lot of sugar and a lot of other contents that may not be helpful for you. Of course, we know really depends on what you're taking with your caffeine before the judgment comes in.

TAGLE: You get the point. Caffeine in general is not a lone bandit out to steal your calm and crib your good health. But some of its closest cronies might be. Standing alone, caffeine actually offers a ton of potential benefits.

IROKU: It's thought that for every one cup of coffee you drink, there's a 3% decrease risk in arrhythmia.

TAGLE: Caffeine is thought to protect your liver from cirrhosis and other liver diseases. Coffee consumption has been shown to reduce risk of Type 2 diabetes and Parkinson's disease. It treats migraine headaches.

IROKU: And the list goes on and on.

TAGLE: So what does healthy caffeine consumption actually look like? The answer will be different for everyone. For her post-doctoral work, Cornelis studied the relationship between the human genome and our coffee and caffeine consumption.

CORNELIS: We found that genetic variants that were related to increased caffeine metabolism were also related to increased caffeine consumption behavior.

TAGLE: What that means is our appetite and tolerance for caffeine is written in our genetic code. So I might naturally be more of a one-coffee-a-day person, and you might be more the three-coffee type. We all have a caffeine sweet spot, but that's not a blank check to consume as much caffeine as you want. The Food and Drug Administration suggests a max of 400 mg of caffeine a day for the average person, the amount of caffeine in about four cups of coffee, because that's an amount not generally associated with dangerous or negative effects. From there, listen to your body.

IROKU: Your body can give you feedback - you know, jitteriness, anxiety, you know, a raised pulse - that you're just consuming too much in a given moment.

TAGLE: If you do feel the need to make a change, Iroku says go slow, consider swaps and don't be scared to experiment. Caffeine should be a helpful friend in your corner, not the boss of you. For NPR's Life Kit, I'm Andee Tagle.

DEGGANS: We have more tips at npr.org/lifekit. Transcript provided by NPR, Copyright NPR.

Andee Tagle (she/her) is an associate producer and now-and-then host for NPR's Life Kit podcast.