Coffee is one of our favorite beverages. But since it's so good, can it be good for us? We dug into the science to find out what coffee does for our health.

Everyone loves coffee (well, almost everyone). It's the third most consumed beverage in the world (behind water and tea). Some people are hooked on it for the energy boost, others for the flavor. Some even savor a warm cup after a big meal, or pair it with dessert. You can have it hot, cold, strong, weak or in a shot. This drink is universally enjoyed, for good reason. But how many calories and how much caffeine does a cup of coffee actually have? And why is it so good for you? We dive into what coffee can do for your heart, brain, liver and mood. Spoiler: it's good news for coffee drinkers.

Coffee Nutrition

Coffee has a lot going for it that is commonly overlooked. Here is the nutrition for one cup (8 ounces) of regular brewed coffee:

5 calories

1 gram protein

0 grams carbs

1 gram fiber

0 grams fat

Though it's not full of macronutrients, coffee (on its own) is a low-calorie beverage that contains several potentially healthful components and is surprisingly high in several nutrients (who knew it had fiber!). Bear in mind, though that cream and sugar can add more calories that you realize, especially when you're buying flavored coffee drinks from a coffee shop. Try to moderate additions to your coffee for the maximum health benefits. For those who don't want to sacrifice the creamy flavor, try a nitro cold brew.

Caffeine in Coffee

The question of how much caffeine is in a cup of coffee does not have a straightforward answer. Many factors, including brewing methods and amounts of coffee used, affect caffeine content. The extended steeping time used to make cold-brewed coffee results in significantly more caffeine being extracted from the grounds and ending up in your cup. It's also important to note that pregnant women are advised to limit their caffeine intake to 200 mg a day or less, which is about the amount in two (8-ounce) cups of brewed coffee. And yes, size matters when it comes to coffee and caffeine. This list of caffeine amounts is per 8 ounces, which is about the size of a small coffee cup (a "short" at Starbucks). Many thermoses and large coffee cups hold much more than 8 ounces. Here are the average caffeine amounts for 8 ounces of several types of coffee:

Regular brewed coffee: 92 mg

92 mg Decaffeinated brewed coffee : 2 mg

: 2 mg Instant coffee: 62 mg

62 mg Starbucks Blonde Roast coffee: 180 mg

180 mg Starbucks Dark Roast coffee: 130 mg

130 mg Espresso (1 2-oz. shot): 127 mg

127 mg Cold-brewed coffee: 283 mg

Image zoom Getty / Abdulrhman Al Shidokhi

Health Benefits of Coffee

Coffee's potential benefits literally reach from your head to your toes. Here are a few of the highlights.

Heart Disease

When you sip on your morning cuppa, you may not be thinking you're doing something good for your heart. Think again! Though coffee can increase your blood pressure for up to three hours after consumption (and people with high blood pressure are advised not to drink large quantities of coffee), research has not linked daily coffee drinking with negative effects on blood pressure and heart disease risk in the long term.

In fact, a 2018 review in the Journal of Agricultural & Food Chemistry found that, in healthy people, drinking 3 to 5 daily cups of coffee was associated with a 15% reduced risk of cardiovascular disease. And no negative effects were found with higher consumption levels. That said, the American Heart Association notes that some recent research results are conflicting, and states only that "moderate coffee drinking (1-2 cups per day) doesn't seem to be harmful."

Scientists credit several components of coffee, and the interaction between them, for its potential heart benefits. One is an antioxidant called chlorogenic acid. This polyphenol is also found in grapes and berries, and coffee actually has a higher amount per serving than blueberries. And caffeine can dilate blood vessels and its anti-inflammatory properties may boost blood flow.

Brain Health

Two to four cups of coffee a day seems to be the sweet spot for a healthy brain. A review in Practical Neurology found that drinking this much coffee had positive impacts on brain health—including increased alertness, concentration and well-being. Other potential benefits of long-term moderate coffee consumption include reduced risk of developing dementia or Alzheimer's disease. Another meta-analysis published in Clinical Nutrition echoed the findings that moderate coffee drinking may protect against cognitive decline. In the short term, caffeine can help relieve pain related to headaches and migraines.

It's thought that two components of coffee, chlorogenic acid and EHT (eicosanoyl-5-hydroxytryptamide), may have a synergistic effect in fending off Parkinson's disease and dementia. Research is ongoing to learn exactly how caffeine affects the brain, but so far it looks promising for coffee drinkers.

Diabetes

A recent study in Current Diabetes Reviews found that people who drank four to seven cups of coffee daily had lower rates of developing type 2 diabetes than those who drank less than two cups a day, especially for people over 60 years old. Additional research, published in Diabetes Care, found that the risk of developing type 2 diabetes over a 20-year period decreased as coffee consumption increased up to six cups daily. This could also be attributed to the caffeine found in coffee.

With these diabetes studies comes another reminder to watch what you add to your coffee. A study in the American Journal of Clinical Nutrition found that consumption of both caffeinated and noncaffeinated sugar-sweetened beverages, like soda, significantly increased risk of developing diabetes, whereas coffee drinking was associated with a 4 to 8% lower risk. If you do drink coffee and want to reap the blood sugar benefits, limit the sugar you add.

Mood Booster

Aside from waking you up, coffee may improve your mood and outlook in a significant way. Consuming up to four cups of coffee a day has been shown to reduce depression risk and alleviate symptoms of depression in women. Furthermore, several studies have found that drinking two to four cups of coffee a day may reduce risk of suicide.

In light of findings like this, caffeine has also been studied as an option for complementary treatment of depression. This does not mean that coffee will totally replace medications prescribed by a doctor, but there are promising findings that it can improve the effectiveness of traditional depression treatment.

Less surprisingly, there is a strong body of evidence that suggests coffee can help with productivity by boosting mental alertness, visual attention and reaction time. Coffee can also make you feel more supported and, in turn, more sociable (cue the office small talk).

Liver Health

Yet again, coffee's antioxidants are credited with potential benefits in numerous liver diseases. While the exact mechanisms aren't clear, there are strong associations between coffee drinking and reduced risk of—and improved outcome of—several liver conditions, including liver cancer, chronic liver diseases and hepatitis C.

Bottom Line

From your head to your heart, a slew of potential benefits are linked to moderate daily coffee consumption. Having two to four cups a day may help keep your heart healthy, stave off cognitive decline and improve symptoms of depression. At the very least, a cup or two of coffee makes for a healthy pick-me-up. Be mindful of how much sugar and cream you're adding, as such add-ins could start to negate some of the beneficial effects of your cup, but go on and feel good about enjoying your morning joe.

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