Caffeine is readily consumed by about 85 percent of Americans one way or another every single day, according to a study published in Food and Beverage Toxicology. That’s quite a buzz! Coffee — caffeine’s most popular vehicle of delivery — has been closely examined by scientists and researchers for years to determine whether or not it’s healthy. Lately, science is tipping the scales toward healthy — a new study revealed even the heaviest coffee drinkers are less likely to die earlier than people who won’t touch the stuff.

“Studies associate coffee drinking with a decreased risk of depression, Parkinson’s disease, type 2 diabetes, liver disease and liver cancer,” says Trevor Rich, M.D., Mayo Clinic Health System in Eau Claire, Wisconsin. “Some of these associations are seen even in drinkers of decaffeinated coffee and may be related to the antioxidants contained in coffee.” Yet, Rich also mentions a study published in Mayo Clinic Proceedings that found moderate caffeine intake — not just from coffee — was also associated with living longer.

Rich’s theory about the antioxidants from coffee seems strong. But scientists have yet to “tease apart” exactly why coffee might be the best source of caffeine, says Dr. Jennifer Temple, Director, Nutrition and Health Research Laboratory at University at Buffalo. “What seems to be consistent is that the health benefits apply to both regular and decaffeinated coffee, so it (the benefits) may not come from caffeine. There are some studies that show that chronic coffee consumption is associated with lower blood pressure, but the mechanism is unclear,” she explains.

How caffeine in coffee (and anything else) works

Derived from plants, caffeine is a stimulant most commonly found in coffee beans, tea, soft drinks, cocoa and chocolate. It enters your blood stream quickly, activating your central nervous system and making you feel more alert around 15 minutes after you have some — an effect that can last for up to 6 hours. Considering 1-in-3 Americans are sleep deprived, according to the CDC, it’s no wonder caffeine is so popular. “Consumption of caffeine is commonly associated with improvements in certain measurements of cognitive performance,” says Rich.

Your nervous system quickly builds a tolerance to caffeine and learns to expect the stimulating effect. It seems addictive because it enhances dopamine signaling in the brain — meaning it’s easier for the feel-good chemical to take effect. Temple says, though caffeine addiction isn’t in the Diagnostic and Statistical Manual of Mental Disorders (DSM) right now, it might soon be — the World Health Organization certainly recognizes that it is addictive. “Many caffeine users become dependent and the latest edition of the DSM has recognized caffeine dependence as a syndrome and are developing diagnostic criteria,” she explains.

How much coffee is safe to drink?

Rich says and research has found, for most people, the equivalent of 3-4 cups of coffee is considered safe to have per day — in fact it’s linked to a lower risk of premature death and heart disease than those who don’t have any.

To make your coffee consumption work for you, U.S. Army researchers have even developed an app called 2B-Alert to determine how much caffeine you should drink — and when you should drink it — to achieve “peak alertness.” The algorithm can reportedly improve performance and attention by up to 64 percent, thus reducing caffeine consumption by up to 65 percent.

How coffee is good for you

Studies galore have confirmed the various health benefits coffee can provide (to some). Drinking as many as 3 cups of black coffee a day may reduce the risk of heart disease, stroke, Alzheimer’s Disease, type 2 diabetes, liver disease and multiple sclerosis. Plus, a study from the Harvard T.H. Chan School of Public Health found heavy coffee drinkers (4+ cups per day) to have a “significantly lower” risk of early death from colorectal cancer.

How coffee is not so good for you

There are, of course, the not-so-pleasant side effects of coffee, like the jitters and heartburn. Also, since coffee is a stimulant, drinking a lot — especially closer to bed time — might not be wise if you have sleep issues though during the day. Heavy coffee consumption (3-4 cups) during pregnancy has been associated with low birthweight and preterm births.

Why can some people drink coffee at night while others can't?

Physically, Rich explains the answer to this question lies in the liver. “Caffeine is metabolized predominantly by the liver. There is an enzyme that takes an active role in this metabolizing process. Any genetic variation in this enzyme may also influence the metabolism speed, which also may partially explain differentiating tolerances and experiences between two given individuals,” he says.

Temple says that tolerance also has a lot to do with it — the more you drink, the more you can tolerate over time.

What's the best way to avoid withdrawal?

Any chronic coffee drinker who’s had to quit or cut down can attest kicking it is no joke — even letting go of a single cup of coffee per day can cause symptoms. “Caffeine withdrawal is a well-evidenced and well-documented clinical experience,” says Rich, who explains withdrawal symptoms most typically start within 24 hours, get to peak intensity within 1-2 days and may last for 1-2 weeks. The most common symptoms are a headache, fatigue, fogginess, a foul mood and difficulty concentrating. “As brutal as it might be, it is relatively short-lived,” says Temple.

What about decaf?

It may be called “decaffeinated,” but decaf coffee still contains caffeine — around 12mgs or more. The good news? You still get the health benefits.

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