Coffee may taste good and get you going in the morning, but what will it do for your health?
A growing body of research shows that coffee drinkers, compared to nondrinkers, are:
- less likely to have type 2 diabetes, Parkinson's disease, and dementia
- have fewer cases of certain cancers, heart rhythm problems, and strokes
“There is certainly much more good news than bad news, in terms of coffee and health,” says Frank Hu, MD, MPH, PhD, nutrition and epidemiology professor at the Harvard School of Public Health.
Researchers don't ask people to drink or skip coffee for the sake of science. Instead, they ask them about their coffee habits. Those studies can't show cause and effect. It's possible that coffee drinkers have other advantages, such as better diets, more exercise, or protective genes.
So there isn't solid proof. But there are signs of potential health perks -- and a few cautions.
If you're like the average American, who downed 416 8-ounce cups of coffee in 2009 (by the World Resources Institute's estimates), you might want to know what all that java is doing for you, or to you.
Here is a condition-by-condition look at the research.
Type 2 Diabetes
Hu calls the data on coffee and type 2 diabetes "pretty solid," based on more than 15 published studies.
"The vast majority of those studies have shown a benefit of coffee on the prevention of diabetes. And now there is also evidence that decaffeinated coffee may have the same benefit as regular coffee,” Hu tells WebMD.
In 2005, Hu's team reviewed nine studies on coffee and type 2 diabetes. Of more than 193,000 people, those who said they drank more than six or seven cups daily were 35% less likely to have type 2 diabetes than people who drank fewer than two cups daily. There was a smaller perk -- a 28% lower risk -- for people who drank 4-6 cups a day. The findings held regardless of sex, weight, or geographic location (U.S. or Europe).
More recently, Australian researchers looked at 18 studies of nearly 458,000 people. They found a 7% drop in the odds of having type 2 diabetes for every additional cup of coffee drunk daily. There were similar risk reductions for decaf coffee drinkers and tea drinkers. But the researchers cautioned that data from some of the smaller studies they reviewed may be less reliable. So it's possible that they overestimated the strength of the link between heavy coffee drinking and diabetes.
How might coffee keep diabetes at bay?
“It’s the whole package,” Hu says. He points to antioxidants -- nutrients that help prevent tissue damage caused by molecules called oxygen-free radicals. “We know that coffee has a very strong antioxidant capacity," Hu says.
Coffee also contains minerals such as magnesium and chromium, which help the body use the hormone insulin, which controls blood sugar (glucose). In type 2 diabetes, the body loses its ability to use insulin and regulate blood sugar effectively.
It's probably not the caffeine, though. Based on studies of decaf coffee, “I think we can safely say that the benefits are not likely to be due to caffeine," Hu says.
Legend has it that coffee was discovered around 850 A.D. in Ethiopia by a goatherd who observed that his animals were unusually lively after eating bright-red berries. Inside those berries were the coffee beans that later went on a global journey. Now, with more than 400 billion cups consumed every year, coffee is the world’s most popular beverage. Coffee has been studied for more than a century and claims a number of health benefits (as well as some risks). Your daily cup of joe may reduce the risk of type 2 diabetes, Alzheimer’s disease, and more. It also packs a powerful punch of antioxidants. In fact, Americans get more antioxidants from coffee than from any other food or beverage. (Want other good sources of antioxidants? You can get your fill of these immune-boosting natural nutrients from artichokes, blackberries, blueberries, cranberries, and potatoes.)
With just two calories per 8-ounce cup (no cream or sugar) and no fat, coffee is a pretty guilt-free way to boost your health. But don’t overdo it. More than 2 or 3 cups daily may increase blood pressure, especially in those with borderline or high readings.
Three-Bean and Coffee Chili
Makes 8 entrée-sized servings
¼ cup olive oil
3 large onions, chopped
6 large garlic cloves, minced
¼ cup chili powder
¼ cup ground cumin
2 tbsp dried oregano leaves
2 28-oz cans crushed tomatoes (with purée)
2 tbsp honey
1 cup strong coffee
2 15-oz cans black beans, rinsed, drained
2 15-oz cans kidney beans, rinsed, drained
1 15-oz can garbanzo beans, rinsed, drained
1 roasted red pepper, seeded and chopped
1 cup chicken stock (can substitute tomato juice or light beer)
1 tsp each: salt, cayenne pepper, ground cinnamon
- Heat olive oil in a large pot over medium-high heat. Add onions and sauté until tender, about 8 minutes. Add garlic and sauté for another minute.
- Mix in chili powder, cumin, and oregano. Cook 1 minute.
- Mix in tomatoes, honey, and coffee. Add drained beans, red pepper, chicken stock, and remaining spices. Bring to simmer. Reduce heat to medium-low and simmer 60 minutes uncovered or until mixture thickens.
- If mixture consistency is too thin, use a potato masher or immersion blender to smash a portion of beans to thicken the chili.
- Optional: Top with nonfat sour cream, chopped avocado, grated low-fat cheddar cheese, chopped green onions, or jalapeño peppers.
Per serving: 403 calories, 19 g protein, 63 g carbohydrate, 8.5 g fat (1 g saturated fat), 1 mg cholesterol, 15.5 g fiber, 1,824 mg sodium. Calories from fat: 19%.