Coffee & Health: What the Science Says


What does a morning without coffee sound like to you? If you answered “scary, sleepy, and confusing”, you’re not alone. Over 80% of U.S. adults drink coffee at least occasionally, and 60% of us drink a cup or more every day. Long considered to be a habit (or a crutch) that delivers a quick boost of energy to power through the day, it’s becoming increasingly clear that the perks of moderate coffee consumption extend far past its ability to wake us up in the morning. Here’s a rundown of some recent, evidence-based findings on one of our favorite hot beverages:

1. Coffee is loaded with beneficial compounds.

Coffee is a simple beverage, but it’s full of complex compounds with health benefits. Although caffeine is the most widely studied compound in coffee, the beverage actually contains hundreds of bioactive components including vitamins, minerals, and anti-inflammatory polyphenols such as flavonoids. There is increasing evidence that drinking coffee is associated with reduced risk for many diseases (more on these later), and researchers think that it’s the combination of these Coffeecompounds in coffee – not any one isolated ingredient that deliver these effects. There is  strong evidence in support of drinking coffee. That’s why the 2015 Dietary Guidelines for Americans committee, noting coffee’s associations with reduced risk of heart disease and type 2 diabetes, commented that up to 5 cups of coffee a day (about 400 mg caffeine) can be incorporated into a healthful dietary pattern. One quick caution about serving size: 1 cup means 8 ounces, so that big tumbler of coffee sitting on your desk might be more than 1 serving. Make sure that you factor in the size of your drinkware to stay within the recommended daily amount. Also, when the Dietary Guidelines talk coffee, they mean straight-up, black coffee, with no additions. We don’t yet know if coffee’s health effects are changed when extras are added in, but we do know that drinking excess calories in coffee adds up quickly, so make sure it fits within your daily calorie budget!

2. Coffee is associated with reduced risk of death for non-smokers.

A paper published just last month studying over 200,000 women and 50,000 men asked how much coffee they consumed, as well as intake of other foods and beverages, and correlated this information to rates of death and disease over the following two decades. They found that non-smokers who drank up to three cups of coffee per day had a 6-8% lower risk of dying than non-coffee drinkers, and people who drank 3 to 5 cups and more than 5 cups per day had 15% and 12% lower death rates. Researchers saw these associations even after taking into account other factors that could influence the outcome, like differences in diet, physical activity, and socioeconomic status between coffee drinkers and abstainers. In addition, both caffeinated and decaffeinated coffee had beneficial effects. This finding indicates that other components in coffee besides caffeine – compounds like flavonoids, lignans, plant alkaloids, and magnesium – may have beneficial health effects that lower inflammation and reduce insulin resistance.

3. Drinking 1-2 coffees per day during pregnancy is safe and does not negatively impact IQ or behavior.

The consensus statement of the American Congress of Obstetricians and Gynecologists declares that up to 200 mg of caffeine per day (about 2 cups) is safe for pregnant women and their developing infants. One recent epidemiologic study correlated biomarkers of caffeine in expectant women’s blood to the IQ and behavioral patterns of their children at ages 4 and 7. It found no association between higher caffeine intake of pregnant women and behavioral problems or lower IQ in children later on. Other studies have also failed to find negative effects of moderate maternal caffeine consumption (2 cups or less per day) on the growth and development of their children. Many of these studies can only prove correlation, and not causation, since randomized trials of caffeine consumption in pregnant women are rare and difficult to conduct. Accordingly, the 2015 Dietary Guidelines for Americans noted that more research should be done in this area, so stay tuned for more findings to come.

Coffee4. Health concerns about compounds in roasted coffee beans are not supported by studies in humans.

Coffee contains a compound called acrylamide, which is naturally formed in some foods during high-temperature cooking processes, including roasting coffee beans. It is also found in other foods that are baked or fried, including potato products like French fries, potato chips, and grains including cereals, whole grain breads, and bakery products. So what’s the worry? Acrylamide was found to be cancerous in studies where animals were exposed to very high doses of the chemical – higher than would normally be possible to ingest by normal food or beverage consumption. A few points to keep in mind: 1) acrylamide has been in our food supply for centuries – ever since we first started cooking, baking, and roasting; 2) no randomized trials have shown dietary acrylamide to be directly harmful to humans; and 3) the low levels present in food are far below the daily human exposure required for any adverse health effects.


It’s important to note that very few of the studies looking at coffee’s long-term health effects in humans are randomized controlled trials – most are observational studies that can only prove associations – not that coffee directly causes (or prevents) the outcomes. However, the evidence is consistent that drinking a few cups of coffee certainly isn’t harmful, and in fact may be beneficial for our overall health. So feel free to enjoy a cup of Joe (or up to five) as part of your daily routine!