Many people rely on a cup of strong coffee to perk up before a long day at the office, and then treat themselves to a frozen latte as an afternoon slump-buster, or enjoy a double espresso after a decadent dinner.
Yet what these coffee lovers may not realize is that coffee may lead to a longer life, even if they drink more than eight cups a day and regardless of whether it’s ground, instant, or decaf.
These are the findings in a new study of nearly 500,000 British adults over a 10-year period that showed that those who drank coffee were likely to live longer than non-coffee drinkers. In the study, published in the American Medical Association’s JAMA Internal Medicine, researchers analyzed the participants’ reported coffee consumption, medical histories, and smoking and drinking habits, and found that coffee drinkers were between 10 and 15 percent less likely to die during that period than non-coffee-drinkers.
So, what is it about coffee that makes it good for your health? Health Matters spoke with Dr. Rekha B. Kumar, an attending endocrinologist at NewYork-Presbyterian/Weill Cornell Medical Center and an assistant professor of medicine at Weill Cornell Medicine, about the study’s findings.
Is it true that this study’s researchers found that coffee may help you live longer?
Yes. What we do know is that coffee drinkers have less of a risk of dying, or a lower 10-year risk of dying. We probably can’t specifically say why or what exact diseases are occurring less, but we can say that, based on this observational study, people who drink coffee have a lower risk of death than people who do not drink coffee.
What is it about coffee and its properties that so positively affect the body?
In terms of what could be healthy about coffee, it does have antioxidants. Those are substances that could be involved in potentially reducing and repairing cell damage, which could lead to disease. We also know that coffee has the potential to decrease inflammation, which could be reducing cancer risk as well as reducing some of the damage that just occurs with the natural aging process.
How does coffee affect how the body uses insulin?
Multiple studies have shown that coffee drinkers may have a lower risk of developing type 2 diabetes. People develop type 2 diabetes when the insulin in their body doesn’t function properly. Insulin is a hormone that we make in our pancreas, and we need insulin to turn carbohydrates into energy. For people who tend to be obese and are at risk for type 2 diabetes, their insulin doesn’t function as well. So they make more and more insulin over time to turn carbs/sugar into energy. Then their pancreas gets tired and eventually gives up, resulting in advanced diabetes, which means they might have to take insulin as a medicine.
How many cups of coffee a day do you need to drink to gain the health benefits that are outlined in this study?
Other studies have highlighted the health benefits of drinking one or two cups a day. What this study really wanted to look at was, “What about the people who just drink a LOT of coffee?” People who drank two to three cups had a lower risk of death than people who didn’t drink any. People who drank six to seven had a lower risk of death and even people who drank eight. I guess you could say we don’t know the upper limits based on the information we have, but the part that was most interesting here was that even heavy coffee drinkers had a lower risk of death. Previously, it’s always been moderate consumption that we thought was beneficial.
Dr. Rekha Kumar
Should people who abstain from drinking coffee start in order to gain the health benefits outlined in the study?
We probably can’t recommend that yet, but what’s interesting is that the study found that even the people who drank decaf showed a benefit. So, it’s apparently not just the caffeine. There are other compounds in coffee, such as antioxidants and other compounds, that may make insulin function better, that are contributing to the mortality benefit and diabetes prevention effect of coffee.
Who should stay away from drinking coffee?
People who may be very sensitive to the stimulant effects of caffeine such as people with hearth arrhythmias, severe anxiety, or insomnia may want to stick with decaffeinated coffee. There are potential harms of coffee too, such as dehydration, acid reflux, and gastrointestinal symptoms, as well as headaches in certain people. Drinking large amounts of coffee, then stopping, can lead to withdrawal symptoms as well.
Could people reap the same benefits if they drank other caffeinated beverages, like tea?
What we can say is that if this mortality benefit was due to caffeine, then tea drinkers should reap that benefit, too. Being that the decaf group also saw positive results, it appears that there are other substances in coffee that are likely contributing to that benefit. If that’s not present in the tea, then we wouldn’t see the same benefit.
What about caffeine in soda?
Although there is caffeine in soda, I do not recommend consuming it because of the sugar and extra calories, and in high quantities it can add acid to the blood and cause bone loss. There are data that suggest both soda and diet soda may contribute to obesity and diabetes, which are both diseases associated with an increase in mortality.
Should people be skeptical about these new findings?
I think we have to take these results with a grain of salt in the sense that it is a prospective study. People were choosing to participate and filling out a questionnaire, which is very different from a randomized trial, where people don’t know what they’re getting and you can measure things differently. What a study like this tells us is that we should look closer at the substances in coffee, other than caffeine, and start studying them individually in a randomized trial.
Dr. Rekha B. Kumar is an attending endocrinologist at NewYork-Presbyterian/Weill Cornell Medical Center and an assistant professor of medicine at Weill Cornell Medicine. She specializes in the diagnosis and treatment of various endocrinology disorders, including obesity/weight management and thyroid disorders. She is also the medical director of the American Board of Obesity Medicine.
Originally published at healthmatters.nyp.org