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What the research says on coffee: Good for you or not?

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More than half of all U.S. adults (54 percent) drink a daily cup of java, and a quarter of Americans drink coffee occasionally. With numbers like these, it’s no wonder that caffeine is the most widely used drug in the world. But, is coffee actually good for you?

It can be hard to tell, judging by contradictory news headlines. No sooner do you read “Coffee can help you live longer,” for example, than you come across “Coffee and the link to premature death.” It’s enough to give a budding health-news consumer whiplash.

In truth, like much-debated red wine and chocolate, coffee is associated with some good and some not-so-good health outcomes.

Here’s a look at the pros and cons:


Rich source of antioxidants

Coffee is the No. 1 source of antioxidants in the American diet. Antioxidants protect our cells from excessive free-radical damage and have an anti-inflammatory effect that protects against all chronic diseases, including heart disease, Alzheimer’s and type 2 diabetes.

Foods like blueberries and pecans actually have more antioxidants ounce for ounce, reports Experience Life magazine, but coffee outstrips them in terms of popularity and consumption. On average, Experience Life notes, coffee drinkers glean more than 40 percent of their daily antioxidants from java.

“Coffee is an amazingly potent collection of biologically active compounds,” Dr. Walter Willett of the Harvard School of Public Health told the National Institutes of Health, the AARP reports.

Protects the brain

Many studies have shown coffee consumption is associated with staving off neurological diseases, such as Alzheimer’s and Parkinson’s, as well as boosting our mental focus. A recent study, published in the journal Nature Neuroscience, shows that caffeine, in particular, has a positive effect on our long-term memory.

Deters diabetes

Various studies have also shown an inverse relationship between coffee consumption and the risk of developing type 2 diabetes. Interestingly, both caffeinated and decaffeinated coffee are associated with a decreased risk of type 2 diabetes.

“It’s becoming increasingly clear that coffee is much more than caffeine, and the health effects that you see for caffeinated coffee are often different than what you would expect based on its caffeine content,” nutritionist Dr. Rob van Dam of the Harvard School of Public Health tells Harvard’s The Nutrition Source.

Armed with this information, the 29 million Americans estimated to have diabetes might be inspired to charge over to Starbucks for a venti Frappuccino. But, says van Dam:

“Keep in mind that the research is typically based on coffee that’s black or with a little milk or sugar, but not with the kind of high-calorie coffeehouse beverages that have become popular over the past few years. A 24-ounce mocha Frappuccino at Starbucks with whipped cream has almost 500 calories — that’s 25 percent of the daily calorie intake for someone who requires 2,000 calories a day. ... This could lead to weight gain over time, which could in turn increase the risk of type 2 diabetes.”

Wards off heart disease

Drinking coffee is associated with lower rates of heart disease. Most likely, experts say, coffee’s antioxidants can take the credit.

“The foundation of heart disease is inflammation of the blood vessels, which is instigated and propagated by free radicals,” Experience Life explains. “And nothing combats free radicals better than antioxidants.”

A cup of coffee contains “a whole host of antioxidants that essentially prevent you from rusting from the inside out,” James O’Keefe, MD, a cardiologist at Saint Luke’s Hospital in Kansas City, Mo., told Experience Life.

Lowers the risk of liver cancer

According to a meta-analysis in Gastroenterology, drinking two cups of coffee a day is associated with a 43 percent reduced risk of liver cancer, Authority Nutrition reports.

Coffee also appears to have a protective effect for the growing number of Americans who have Non-Alcoholic Fatty Liver Disease. “No one really knows how caffeine works on [fatty liver disease],” George Mason University (GMU) researcher Zobair Younossi told GMU’s Mason Research magazine. There might be a component in caffeine that reduces liver inflammation, he said, or maybe caffeine has an antioxidant effect.

Boosts athletic performance — legally

It’s widely accepted that drinking a cup of coffee before working out can supercharge your performance, especially in endurance sports. The Huffington Post explains that caffeine “increases the number of fatty acids in the bloodstream, which allows athletes' muscles to absorb and burn those fats for fuel, therefore saving the body's small reserves of carbohydrates for later on in the exercise.”

Coffee also acts on the brain, triggering it to release endorphins, reports Experience Life magazine, “which raises a person’s pain threshold,” something that might be helpful — at least in the short term — during an athletic event.


Increases anxiety, stress and insomnia

It’s common knowledge that too much coffee can give you the jitters and disrupt your body’s internal clock. “The effect is so reliable,” Laura Juliano, PhD, a caffeine researcher at American University in Washington, D.C., tells Experience Life magazine, “that researchers who study anxiety use caffeinated coffee to incite feelings of anxiousness in study participants.

Not everyone responds to caffeine equally, says Dr. Mark Hyman, the medical director of the Cleveland Clinic’s new Center for Functional Medicine. Even a little coffee can produce the shakes for some folks, he told The Huffington Post:

“Some metabolize coffee differently than others. Our detoxification pathways are genetically determined. That is why some people have one cup in the morning and can't sleep for days and others can have a double espresso after dinner and hit the pillow and fall into deep sleep. The gene involved is called CYP1A2. You can get a lab test to find out if you have trouble detoxifying.”

The silver lining? If you are not genetically susceptible to coffee’s effects, you may be able to guzzle it with relative impunity.

Irritates the gut

As many of us can personally attest, coffee can wreak havoc on our bellies. Coffee increases the production of our stomach’s gastric juices, Experience Life reports, which can cause heartburn and increase symptoms of irritable bowel disease.

Can be addictive

Caffeine is a drug. As such, folks can become hooked and have a hard time kicking the coffee habit without suffering withdrawal symptoms, such as fatigue, irritability and headaches, caffeine researcher Juliano tells PsychCentral.

“The negative effects of caffeine are often not recognized as such because it is a socially acceptable and widely consumed drug that is well integrated into our customs and routines,” Juliano, who completed a recent study on caffeine dependence in the Journal of Caffeine Research, told PsychCentral:

“There is misconception among professionals and lay people alike that caffeine is not difficult to give up. However, in population-based studies, more than 50 percent of regular caffeine consumers report that they have had difficulty quitting or reducing caffeine use.”

Mark Hyman remembers his days of caffeine dependence all too well. “During my emergency room days, I would power up with a quadruple espresso and work from 11 p.m. to 7 a.m.,” he told The Huffington Post. “Just like a drug addict, I needed more and more just to stay barely functional. My sleep was difficult, more interrupted and less restful, and I woke tired and in need of my ‘fix’ of java.”

In 2013, PsychCentral reports, the American Psychiatric Association officially recognized “Caffeine Use Disorder” in the DSM-V — the standard list of mental disorders — as a condition that merits additional research.

Interacts negatively with some medications

Consuming large amounts of caffeine while taking some common medications, such as Tylenol, can cause liver damage, Mark Hyman tells The Huffington Post.

Pesticide-intensive crop

Conventionally grown coffee is heavily sprayed with pesticides, reports Prevention, so it’s best to opt for organic coffee when possible.

Not all decaf is created equal

Prefer your coffee unleaded? Choose coffee that has been decaffeinated using the Swiss Water Process, The Huffington Post reports, instead of through the use of chemical solvents.

Conventional decaffeination processes often rely on methylene chloride, according to Experience Life magazine, which has been shown to be carcinogenic in lab animals, or ethyl acetate, which wipes out many of the beneficial antioxidants found in coffee.


In sum, coffee may have some health benefits, says Harvard’s Rob van Dam, “but more research needs to be done.”

Also, it’s important to remember that while many coffee studies have found an association between good health and coffee drinking, researchers don’t know a lot about what specifically causes the health benefits.

“It could be, for example, that coffee drinkers are more active and social,” AARP reports. “Or it could be that one of the more than 1,000 compounds that coffee natural contains boosts our health. We don’t know.”

So, where does that leave us?

It comes down to the individual, says van Dam: “If you’re drinking so much coffee that you get tremors, have sleeping problems, or feel stressed and uncomfortable, then obviously you’re drinking too much coffee.”

If coffee suits you just fine, though, drinking it in moderation is no problem. Just remember not to overdo it when it comes to your daily caffeine intake — “that big cup of soda and your favorite chocolate bar also contain caffeine,” AARP reminds us.

And, remember, if you’re simply looking to boost your antioxidants, you could always just eat some more blueberries.

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