Is Coffee Actually Good For You? The Answer Is More Complicated Than You'd Think

mug of coffee on a stack of books next to a cactus; is coffee good for you?
POPSUGAR Photography | Lexi Lambros
POPSUGAR Photography | Lexi Lambros

Lorelai Gilmore. Pretty much every character in Friends. The person writing this article (hi, it's me). What do all of these folks have in common? An obsession with coffee — and for good reasons.

Let's start with the most obvious: Coffee is chock-full of caffeine. As a stimulant, caffeine has the power to perk you up on even the dreariest of mornings and refuel your focus when your brain starts to burn out around 3 p.m. Plus, as Gilmore and Monica Geller show us on TV, there's something incredibly comforting about the ritual of sipping on a freshly brewed cup of Joe.

But that's not all. Coffee is actually a rich source of compounds that may help ward off health conditions, such as cardiovascular disease and dementia, as well as improve performance in the gym or on the field.

Keep reading to learn more about the benefits of coffee, and why you might want to start — or keep! — brewing a daily cup of java.

Coffee Nutrition

While it's not exactly a notable source of macronutrients (e.g. protein, carbohydrates, fat), coffee does contain some star micronutrients, including vitamin B2 and magnesium, according to the Harvard T.H. Chan School of Public Health. It's also rich in antioxidants, such as polyphenols, plant compounds with anti-inflammatory properties, says Keri Gans, RDN, author of "The Small Change Diet" and host of the podcast "The Keri Report." (Spoiler alert: These compounds are responsible for many of coffee's health benefits.)

When talking about coffee's nutrition facts, you can't forget about caffeine, a mild stimulant. An 8 oz. cup of coffee contains about 80 to 100 mg of caffeine, according to the United States Food and Drug Administration (FDA). (For reference, the FDA estimates that an 8 oz. cup of black tea contains 30-50 mg of caffeine.) The exact amount of caffeine in coffee also depends on factors such as how and where the beans were grown, processed, and brewed.

Here's an example of the basic coffee nutrition facts for one cup of the beverage prepared with tap water and without any cream or sugar, according to the United States Department of Agriculture.

  • Calories: 2.4
  • Protein: 0.3 g
  • Fat: 0.1 g
  • Carbohydrate: 0 g
  • Fiber: 0 g
  • Sugar: 0 g

Keep in mind that these benefits and nutrition facts associated with coffee are for plain black coffee. Some coffee-based beverages, such as Starbucks's signature Frappuccinos or flavored lattes can contain additional sugar, fat, carbs, and protein, depending on what's included in the drink.

Health Benefits of Coffee

Boosts Alertness

Sure, caffeine might seem like magic, especially on Monday mornings. But it actually works by affecting the central nervous system in the brain. Caffeine works by blocking the receptors of adenosine, a neurotransmitter that mediates brain functions such as sleep, cognition, memory, and learning. Blocking the receptors of adenosine, in turn, increases alertness and decreases fatigue, according to Tufts University Gerald J. and Dorothy R. Friedman School of Nutrition Science and Policy.

That being said, this caffeine-caused benefit isn't actually a benefit for everyone. "Everyone metabolizes caffeine differently," says Samantha Ferguson, MS, RD, LDN, a registered dietitian at Wellory and Pivot Nutrition Coaching. Some people might be more sensitive to the stimulant (and, in turn, coffee) and experience anxiety, jitteriness, and an elevated heart rate, offsetting any energizing effects.

May Lower the Risk of Diabetes

"It is believed that coffee has the ability to protect and maintain the function of the beta cells in your pancreas, which are responsible for producing insulin," Ferguson says. "Insulin helps regulate blood sugar levels, therefore reducing the risk of type 2 diabetes." In fact, a review of 30 studies found that each cup of coffee consumed by people per day was associated with a 6 percent decreased risk of developing the disease.

"Due to the anti-inflammatory benefits of antioxidants found in coffee, such as polyphenols, coffee may help decrease metabolic inflammation," Gans adds. "Metabolic inflammation is known to lead to the progression of the disease [type 2 diabetes]."

May Ward Off Heart Disease

Research suggests that mild-to-moderate coffee consumption (i.e. 2 to 3 cups per day) can reduce the risk of cardiovascular conditions, such as coronary heart disease, heart failure, and arrhythmia. Studies also show that drinking around this amount of java daily can be associated with a 21 percent lower risk of stroke. Being that coffee has hundreds of biologically active compounds, there could be many reasons why the beverage can have these beneficial cardiovascular effects. That being said, the polyphenols in coffee might play a key role, Gans explains, as they are known to reduce oxidative stress and inflammation — two factors that are thought to contribute to heart disease.

May Enhance Athletic Performance

Coffee is often used by athletes looking to improve performance and increase energy levels, Ferguson says. A review of nine studies found that drinking coffee before exercise improved people's endurance and decreased their perceived exertion (how hard they feel like they're working). Additional research has also shown coffee boosts endurance, improves circulation, increases muscular strength and power, and reduces pain.

Potential Risks of Coffee

As mentioned, everyone processes caffeine differently. Folks who metabolize caffeine slowly — a characteristic that you're seemingly genetically predisposed to, according to the Cleveland Clinic — might experience anxiety, elevated blood pressure and heart rate, and restlessness, among other negative effects. Even if you normally don't have any trouble drinking coffee, you could encounter similar symptoms if you drink more than usual (thus consuming a higher dose of caffeine), Ferguson says.

"For some individuals, coffee consumption can [also] lead to gastrointestinal distress," Gans says. "Caffeine is a stimulant that may increase gut movement, and because of that, some people experience diarrhea." The beverage also contains many acids that have been shown to increase stomach acid; it's possible that this can result in GI upset as well as acid reflux, according to research.

ICYDK, caffeine has a diuretic effect, according to the Mayo Clinic, meaning it increases the production of urine (i.e. fluid loss). Because of this, coffee has long been labeled as dehydrating — but is it really? According to studies, that answer is "no." Research shows that after about four days of consistent caffeine consumption, your body adjusts and develops a tolerance against the diuretic effect.

Another side effect of your body becoming more accustomed to your daily brew? Dependence, "specifically for the pick-me-up that caffeine provides," Gans says. Research shows that regular caffeine consumption can cause neurochemical changes in the brain that can lead you to build a tolerance. In other words, over time, you might find yourself needing to bump up your intake to get the same caffeine-related effects, such as alertness and boosted concentration, that you once were able to achieve just from one cup of Joe.

If you have difficulty starting or getting through your day without multiple cups of coffee, you might want to consider your caffeine intake. "Taking a break from drinking coffee (or caffeine in any form) can help lower this tolerance again," Ferguson says.

So, Is Coffee Good or Bad For You?

"Coffee can definitely be a healthy beverage," Gans says. It can offer some promising health benefits but it also has some risks, and exactly how you prepare it and how much you drink does determine how "healthy" it is. Plus, as with pretty much every other drink and eat out there, moderation is key. And on that note . . .

How Much Coffee Is Too Much?

In general, 400 mg of caffeine a day — about 4 or 5 cups of coffee — is generally not associated with dangerous or negative side effects, according to the FDA. "But keep in mind that for some people, even 100 mg of caffeine may not agree with them, and therefore coffee would not be a wise choice of a beverage," Gans says. If you experience adverse side effects, that's likely a sign that the amount of brew you consumed might be too much for you. Pro tip: Take note of the amount and keep it in mind for future coffee orders or runs with friends.

Caffeine Intoxication

Drinking too much caffeine can have serious side effects, and — although rare — caffeine intoxication is a real possibility. According to Mount Sinai, caffeine intoxication, otherwise known as caffeine overdose, can result in convulsions (seizures) and even death. Symptoms include difficulty breathing, irregular heartbeat, dizziness, diarrhea, fever, muscle twitching, and increased thirst and urination. If you suspect you may be suffering from caffeine intoxication, you can call the national Poison Help hotline at 1-800-222-1222. Treatment may include activated charcoal, laxatives, medicine, IV fluids, and/or breathing support via oxygen or ventilator.