Another giant study confirms that your coffee habit is probably good for you

Here’s the thing about coffee: there’s never been much scientific debate about whether it’s healthy. Yes, people have been concerned about it since the 16th century, but as long as we’ve been analyzing its effects we’ve observed that drinking coffee tends to improve your health, not harm it. In moderation, of course.

The fear that coffee harms us is pervasive, though, and as a result it feels like there’s been a lot of back-and-forth. One day it’s good for you. The next it’s bad. In reality, the large-scale analyses of the harms or benefits of a cup o’ joe have pretty much all shown definitive upsides, or at the very least no effect at all. It's not going to cure all that ails you or make you live forever, but most evidence suggests coffee is part of a healthy diet.

On Monday, another of these giant studies came out, this time looking at residents of the United Kingdom. Researchers there wanted to examine how coffee habits affected overall health, as measured by a statistic called all-cause mortality. That basically means they grouped people by how many cups of coffee they drank per day, then looked to see whether those groups that consumed more cups had more deaths during the course of the study. If the cohort that drank eight cups per day had fewer deaths than the group that drank just two, that would imply that somehow the high-volume coffee drinkers were more healthy. And that’s exactly what they found. Across 502,641 participants ranging from 38 to 73 years old, both male and female, the more coffee a person drank the less likely they were to die. The researchers published their results in JAMA Internal Medicine on Monday.

RELATED: Coffee makes you a better person 

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12 ways coffee makes you a better person
Coffee can help you see the positives. 

Let's give it up for coffee's ability to help you identify the positive things! A small study found that, when tasked with identifying positive and negative words, study participants who took the equivalent of two to three cups of caffeine identified positive words and images faster than negative ones. Think of coffee as a silver bullet for optimism.

Coffee gives you an energy jolt in as little as 10 minutes.

Hello, instant energy. Studies show that caffeine from coffee hits the bloodstream in mere minutes, though it will take a bit longer to feel its full effect. You'll feel unstoppable (i.e. your most alert) roughly 30 to 45 minutes after downing your java, research suggests. Patience is a virtue, okay? 

Coffee helps you poop.

Coffee wakes up your mind and your bowels. Three out of every 10 people find that coffee has a laxative effect, and researchers have found that coffee gets the digestive system going by stimulating the "distal colon," the Washington Post noted. Decaf can still do the trick, too.

Coffee makes you more alert when driving.

If you've got a long, monotonous drive ahead of you, you may want to down that caffeinated slurry at the highway rest stop. One study with 24 participants found that just one cup of coffee helped sleep-deprived drivers have better control of their vehicles and weave less frequently.

The smell of coffee can relax you.
Start feeling revived the moment you smell coffee brewing? It's not just in your head. One study on rats found that a whiff of hot coffee changed the proteins and genes in the animals' brains. Stressed rats exhibited more relaxed brains after smelling coffee compared to a control group of stressed rats that did not smell coffee.
Coffee helps you focus — even when you're sleep deprived.

You probably don't need us to tell you that the caffeinated drink wakes up your brain. But science confirms it does — by a long shot. One study found that 200 mg of caffeine (equivalent to about two cups of coffee that have 95 mg of caffeine each) helped sleep-deprived U.S. Navy SEALs have better memory and brain functioning.

Coffee makes you smarter.

Coffee won't magically give you extra IQ points. But the stimulant can make help your brain be more efficient with its resources it, CNN reported.

"When you're sleep-deprived and you take caffeine pretty much anything you measure will improve: reaction time, vigilance, attention, logical reasoning — most of the complex functions you associate with intelligence," Harris Lieberman, a research psychologist at the Military Nutrition Division of the U.S. Army Research Institute of Environmental Medicine, told CNN. "And most Americans are sleep-deprived most of the time." Guilty as charged...

Coffee can help you live longer.
We'll all die one day, but studies show a daily coffee habit is linked to a longer life. You can't achieve immortality with a macchiato but then again, can't hurt to try... if you're into not dying.
It cuts your risk for Type 2 diabetes.
Both Type 1 and Type 2 diabetes are serious diseases that change how your body processes glucose (blood sugar) and negatively impact life expectancy. Researchers found that drinking two cups of coffee a day was associated with a 12% decreased risk for developing Type 2 diabetes.
Coffee might help prevent depression.

A jolt of energy makes most of us instantly happier, but coffee could have positive long term effects on our moods. One study found that women who drank 2 to 3 cups of coffee per day had 15% decreased risk for developing depression during the 10 years of the study. Women who drank decaf didn't exhibit the lower risk for developing depression.

Coffee protects your brain from aging.
To stave off conditions like Alzheimers and dementia, drinking some extra cups of joe might help. One study found that middle-aged people who drank three or more cups of coffee a day had a decreased risk of developing dementia later in life.
Coffee makes you a better athlete.
Trying to go HAM during your next gym sesh? Pre-game your workout with coffee and you'll perform better. Science says the caffeine in coffee can increase endurance. Now run, Forest, run [to the closest coffee shop].
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The differences weren’t giant, but they were statistically significant. This is getting a little into the weeds here (skip down a paragraph if you hate statistics), so bear with for a moment. When doing a large observational study like this, researchers use a hazard ratio to measure how much of an effect a variable like coffee consumption has. For example, in this case a hazard ratio of 1 means there’s no difference in how often people die, whereas a hazard ratio of 0.5 would mean the group that drank coffee died only half as often as the non-coffee drinkers. This study grouped participants into six cohorts: those who drank less than one, one, two to three, four to five, six to seven, and more than eight cups of coffee per day. The researchers found that the hazard ratios generally declined as the number of cups consumed increased, indicating that the more coffee people drank, the less likely they were to die during a set period. In order, the hazard ratios were 0.94, 0.92, 0.88, 0.88, 0.84, and 0.86. All but the first ratio are considered statistically significant—meaning that the difference between the groups was profound enough to (probably) be more than random chance.

Studies like this can only ever tell us what health outcomes tend to look like for people who drink coffee. They’re observational—no one is assigning groups of participants to drink five or two or zero cups per day and then making sure their lives are otherwise identical, so they can’t provide any real causation. But because we’re never going to run a clinical trial in which coffee gets prescribed, observational studies are the closest we’ll get. That’s why it’s important to gather a lot of people—hundreds of thousands or even millions are ideal—so that you can be assured that your finding isn’t just a statistical fluke. Drinking coffee may be associated with lots of other habits that influence health, or perhaps not drinking coffee is associated with something. For instance, people who have serious illnesses like cancer may not drink coffee, but these people are also more likely to die—that would artificially increase mortality for the non-coffee-drinking group.

RELATED: Cities for coffee lovers 

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Best cities for coffee fanatics
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Best cities for coffee fanatics

10. Denver, Colorado

Denver fell two spots this year to round out the top 10 best cities for coffee lovers. The Mile High City has four local roasters, which is more than many cities in the country. Plus, it has top 20 scores in both total number of coffee shops and cafes, and coffee shops and cafes per 100,000 residents.

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9. San Francisco, California

San Francisco is steeped in coffee history. It is the birthplace of world-famous brands like Folgers and MJB. Coffee culture in San Francisco, despite its long history, has also kept up with modern trends. There are more coffee shops and cafés per residents in San Francisco than any other city in the country at 302 per 100,000 residents.

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8. Oakland, California

Oakland comes in one spot above its Bay Area neighbor to claim eighth place. Oakland is the birthplace of notable coffee spots like Blue Bottle Coffee and Oakland Coffee Works (founded by members of the band Green Day). Oakland also has some of the most enthusiastic coffee lovers in the country. Oakland residents Google “coffee” 39% more than the U.S. average.

Check out our budget calculator.

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7. Tampa, Florida

Tampa is a newcomer to this year’s top 10 best cities for coffee fanatics. Coffee drinkers in Tampa have access to great and also cheap coffee. Tampa has the lowest average cost of a cappuccino in our top 10 at $3.53. Plus 33% of its coffee places are rated 4.5 stars or higher. The one concern may be the lack of variety, as there are relatively fewer coffee places in Tampa as compared to the other cities in our top 10.

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6. Austin, Texas

Folks in Austin have an abundance of options when it comes to great coffee. Over 33% of coffee places here are rated 4.5 stars or above. Vintage Heart Coffee may be the best among a great bunch, with Yelp users claiming it serves the best cold brew in Austin. A good cold brew is a must in a place like Austin, which can get pretty steamy in the summer.

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5. New Orleans, Louisiana

For coffee fanatics looking for something different, head to New Orleans. The local custom here is to mix chicory in with the coffee to create a unique flavor and experience. Why this is done is a bit of a long story, but if you are in town be sure to give it a try. New Orleans also has seven roasters local to the city so getting the freshest, most flavorful coffee beans should be no trouble.

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4. Portland, Oregon

Portland ranks fourth in this year’s study, down one spot from last year. If you are a coffee tourist, Portland may be the best city to explore first. It has the highest percentage of highly rated coffee places in the country. Portland is also the hometown of famed roaster Stumptown Coffee Roasters, as well as 12 other roasters, a good sign for people who love their coffee super fresh.

Moving to Portland? Here are 15 things you should know.

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3. Honolulu, Hawaii

If you are a java lover in Honolulu, you aren’t alone. Google searches for “coffee” in Hawaii’s capital are 84% higher than the national average. For coffee fanatics looked to discuss their fanaticism over a cup of coffee, opportunities will be plentiful. Honolulu has the fifth-most coffee places per 100,000 residents at 243.

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2. San Diego, California

San Diego ranks as the second-best city for coffee fanatics. Last year, it took the sixth spot in our list. Few cities were able to beat San Diego coffee spots in terms of quality. Data from Yelp shows that 37% of coffee places in San Diego score above 4.5 stars. Coffee fanatics visiting San Diego may want to check out Holsem Coffee or Bean Bar.

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1. Seattle, Washington

Unsurprisingly, the birthplace of Starbucks, Caffe Vita, Seattle’s Best Coffee and Tully’s Coffee is ranked as the best city for coffee fanatics. Try as you might it’s tough to see what a coffee fanatic would not love about Seattle. It ranks highly in every single one of our metrics except price. In terms of availability, Seattle has the third-most coffee places per capita in our study and in terms of quality, 31% of its coffee places were rated a minimum of 4.5 stars by Yelp users.

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The researchers in this study looked to see which other traits were associated with drinking lots or no coffee—things like smoking, body weight, socioeconomic status, and so on—and tried to control for those factors to prevent them from interfering with the results. Coffee drinkers tended to be male and white, for example, and also drank more alcohol and were former smokers. Particularly high coffee consumption was correlated with being a current smoker. Drinking between one and three cups correlated with having a university degree and being older, and well as reporting “excellent” health.

All of these findings generally line up with what other large-scale studies have found: drinking more coffee tends to correlate with good health and fewer deaths. Here is a 2017 European study showing that, with 521,330 people. Here’s one from 2012 involving 5,148,760 Americans finding the same inverse correlation. And here’s another from 2017 focusing on nonwhite populations in the U.S., still finding that drinking coffee is generally associated with lower risk of death.

This study is, for the most part, the same as the rest, except for one thing: it looked at genetic variations in caffeine metabolism. Relatively recent work has established certain mutations that make a person respond to caffeine in different ways. Researchers think this may partly explain why some people can down a cappuccino after dinner and sleep fine, whereas others have to stop drinking joe after 4 p.m.

Related: Add this to your coffee 

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Strangely delicious things to add to your coffee
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Strangely delicious things to add to your coffee
Butter

Butter in coffee is actually becoming a very popular trend, among celebrities like Shailene Woodley and college students alike. The mixture, termed "Bulletproof Coffee," is made by blending together coffee with a pat of butter and some coconut oil.

The nutritional benefits behind this seemingly odd drink include improved work performance, higher and prolonged energy levels, and weight loss. Use grass-fed butter, which is a heart-healthy superfood rich in antioxidants and body fat-burning vitamins. Who said butter wasn't good for you?

Salt
No, I don't mean sugar. Some people claim that adding sugar to coffee decreases its bitterness (we're looking at you, dining hall coffee). If you make your own coffee at home, try adding it to your coffee grounds before brewing, or to your cold brew to really maximize the flavor.
Cardamom
Make your morning coffee exotic by adding this Middle Eastern spice to your cup, which also acts as a neutralizer for the effects of caffeine. If you're one of those people who gets the jitters from coffee, I'm talking to you. Cardamom was also commonly used in Ayurvedic medicine to lift spirits, reduce pain, and induce a calm state of mind. As a bonus, it can also help stimulate your appetite and settle your stomach. This might just be the miracle spice you've been dreaming of.
Egg
And you thought the butter was weird. Scandanavian egg coffee is a traditional drink in parts of Scandinavia, Norway, and even the American Midwest. It's made by mixing a whole raw egg into coffee grounds, then boiling it in water. It results in a separation of the coffee grounds and the water, free of sediment or cloudiness. Straining it results in an amber-colored coffee that is only mildly bitter and that still contains the essential oils from the coffee beans. It's definitely an experiment worth trying.
Ice Cream
Because why not? I can personally say that ice cream is probably the greatest addition to coffee that's ever happened. It's the perfect substitute for cream and sugar, making your coffee that much sweeter and easier to drink if you actually hate coffee, but drink it anyway to stay awake. If your college dining hall has an ice cream machine, I would recommend topping off your cup of joe with a scoop of your flavor of choice, and revel in the luxury of your new favorite drink.
Coconut Oil
Coconut oil is used in pretty much everything these days, so why not add it to your coffee too? Advocates maintain that coconut oil enhances coffee, making it taste better and providing a whole lot of health benefits. A spoonful of the stuff will help speed up your metabolism, boost your immune system, and leave you feeling more satisfied.
Oatmeal
Breakfast and coffee in one? Yes, please. Decrease your morning routine by adding raw oatmeal into your hot cup of coffee until the oatmeal is cooked through. Add cinnamon, honey, or sugar for extra flavor and sweetness. As a bonus, there's one less set of dishes you have to do. It's a win-win.
Tonic Water
Bubbly iced coffee sounds weird but also somewhat appealing, right? This combination, popular in places like Sweden, is made by pouring cold brew or espresso over tonic water and ice. The resulting drink is said to be citrusy, crisp, and refreshing (especially on those hot summer days), with an additional caffeinated kick you'll probably need once exams start. By night, turn this drink into a cold brew gin and tonic, because you deserve it.
Lemon or Lime
First there was lemon in water, now there's lemon in coffee. Give your morning brew a citrusy kick by throwing in a fresh lemon or lime peel (but be careful not to swallow it). The peel will get rid of the bitter flavors of your coffee and enhance its sweetness. Another myth suggests that a lemon peel can clean your teeth after drinking coffee or espresso. Unfortunately, however, it can't prevent coffee breath.
Coca-Cola
The more caffeine the merrier. For the ultimate pick-me-up, pour some Coca-Cola into your iced coffee, making a drink that's said to be similar to vanilla Coke. The mixture results in a refreshing fizz that's bubbly and sure to keep you awake throughout most of the day. Be sure to use a medium to dark roast coffee in order to decrease dilution and counteract the sweetness of the soda.
Vanilla Extract
Pure vanilla extract is a great replacement for any artificial sweeteners or sugars that you would typically use in your coffee. Just a few drops of the stuff will sweeten your brew and add additional flavor minus all the fake preservatives in traditional flavor syrups. You could also try adding almond extract to experiment with flavor profiles.
Sweetened Condensed Milk
You're never going to want to put regular milk in your coffee again after you try it with this stuff. Sweetened condensed milk added to your coffee will make it sweeter and creamier, requiring no extra sugar. A traditional drink in Vietnam, it's super easy to make and way cheaper than any of the lattes at Starbucks you usually get.
Peanut Butter
This was actually an experiment of my own, as I have a slight huge obsession with peanut butter and would try to eat it with everything if I could. Peanut butter will give your hot coffee a nutty, creamy taste, and provide all the benefits that come with eating it. This includes added protein to help make you feel fuller longer, healthy fats, fiber, and potassium. You could even blend coffee and peanut butter with some other ingredients to create a satisfying morning coffee smoothie.
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The U.K. researchers used a large database containing genetic information about participants to test whether certain variants correlated with better or worse health outcomes. Perhaps those that respond quickly and easily to caffeine would fare worse—they just weren’t sure. But even looking across 400,000 people for whom genetic data was available, the researchers found no difference in outcomes between those whose genes predisposed them to caffeine sensitivity and those who didn’t. That is, across genetic variants, those who drank more coffee tended to have lower risk of death.

They did find, somewhat unsurprisingly, that those with a higher “caffeine metabolism score”—those who metabolize caffeine faster—tended to drink more coffee.

If you’re one of those people who can’t have more than a cup without getting jittery, but still want to drink joe, don’t worry—you can drink decaf and still get the health benefits. This study, like others, found that the caffeine content made no difference to the risk of death. Even instant coffee seems to work, though the researchers note that the associations for ground, caffeinated coffee were “generally stronger.” Researchers aren’t sure what’s in coffee that seems to boost our health, but the scientists on this study noted it provides further evidence that the secret ingredient isn’t caffeine. Christopher Gardner, a professor studying food and health associations at the Stanford Prevention Research Center, told NPR that it may be the many antioxidant-rich compounds in our morning brew. One 2005 study in JAMA suggested that it could be compounds that reduce inflammation and insulin resistance, like lignans, quinides, and magnesium.

RELATED: Chains that rival Starbucks 

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10 coffee chains predicted to be the next Starbucks
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10 coffee chains predicted to be the next Starbucks

Joe Coffee

Number of locations: 16

States: New York, Pennsylvania

Photo credit: Facebook

Colectivo Coffee Roasters

Number of locations: 17

States: Washington, Illinois

Kaldi's Coffee

Number of locations: 18

States: Missouri, Georgia

Thomas Hammer Coffee Roasters

Number of locations: 18

States: Washington, Idaho

Woods Coffee

Number of locations: 19

States: Washington

Gregorys Coffee

Number of locations: 26

States: New York, New Jersey

La Colombe Coffee Roasters

Number of locations: 26

States: New York, Pennsylvania, Illinois, Washington D.C.

Blue Bottle Coffee Company

Number of locations: 35

States: California, New York, Washington D.C.

Philz Coffee

Number of locations: 40

States: California, Washington D.C.

Black Rock Coffee Bar

Number of locations: 42

States: Oregon, Washington, Arizona, Idaho, California

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Of course, none of this means that coffee isn’t an addictive substance or that pregnant people should be chugging it (the American College of Obstetricians and Gynecologists recommends no more than 200 milligrams per day, or about two cups of coffee). Caffeine is a stimulant, and though “too much” depends on your personal metabolism, an overload can give you headaches, irritability, restlessness, a fast heartbeat, and muscle tremors. Plus it can deprive you of sleep. The Mayo Clinic recommends limiting yourself to about 400 milligrams a day for that reason. It also doesn’t mean that you can put oodles of sugar and cream in without having other negative health effects, like obesity or heart disease. But it does mean that the average person can drink their moderately-sugared, lightly-creamed joe in peace—even though we already knew that.

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