LONDON — Greater consumption of coffee could lead to a longer life, according to two new studies published Monday.
The findings have resurfaced the centuries-old conversation on coffee’s health effects.
One study surveyed more than 520,000 people in 10 European countries, making it the largest study to date on coffee and mortality, and found that drinking more coffee could significantly lower a person’s risk of mortality.
The second study was more novel, as it focused on non-white populations. After surveying over 185,000 African-Americans, Native Americans, Hawaiians, Japanese-Americans, Latinos and whites, the researchers found that coffee increases longevity across various races.
People who drank two to four cups a day had an 18% lower risk of death compared with people who did not drink coffee, according to the study. These findings are consistent with previous studies that had looked at majority white populations, said Veronica Wendy Setiawan, associate professor of preventative medicine at USC’s Keck School of Medicine, who led the study on nonwhite populations.
“Given these very diverse populations, all these people have different lifestyles. They have very different dietary habits and different susceptibilities — and we still find similar patterns,” Setiawan said.
The new study shows that there is a stronger biological possibility for the relationship between coffee and longevity and found that mortality was inversely related to coffee consumption for heart disease, cancer, respiratory disease, stroke, diabetes and kidney disease.
The study on European countries revealed an inverse association between coffee and liver disease, suicide in men, cancer in women, digestive diseases and circulatory diseases. Those who drank three or more cups a day had a lower risk for all-cause death than people who did not drink coffee.
Both studies were published in the Annals of Internal Medicine.
“We looked at multiple countries across Europe, where the way the population drinks coffee and prepares coffee is quite different,” said Marc Gunter, reader in cancer epidemiology and prevention at Imperial College’s School of Public Health in the UK, who co-authored the European study.
“The fact that we saw the same relationships in different countries is kind of the implication that its something about coffee rather than its something about the way that coffee is prepared or the way it’s drunk,” he said.
The biological benefits — and caveats
Coffee is a complex mixture of compounds, some of which have been revealed in laboratories to have biological effects, Gunter said.
Studies have shown that certain compounds have neuroprotective and anti-inflammatory properties that can help reduce risk for illnesses like Parkinson’s disease.
In the European study, people who were drinking coffee tended to have lower levels of inflammation, healthier lipid profiles and better glucose control compared with those who weren’t. It is still unclear which particular compounds provide health benefits, but Gunter said he would be interested in exploring this further.
Both studies separated smokers from nonsmokers, since smoking is known to reduce lifespan and is linked to various deceases. However, they found that coffee had inverse effects on mortality for smokers too.
“Smoking doesn’t seem to blunt the effects of coffee,” Gunter said. “It didn’t matter whether you smoked or not. There was still a potential beneficial affect of coffee on mortality.”
However, Dr. Alberto Ascherio, professor of Epidemiology and Nutrition at Harvard T.H. Chan School of Public Health, said people should be wary of this finding.
“Even if it was in some way true, it doesn’t make sense to me, because by smoking, you increase your mortality several-fold. Then, if you reduce it by 10% drinking coffee, give me a break,” said Ascherio, who was not involved in the study.
“I think it’s a dangerous proposition because it suggests that a smoker can counteract the effects of smoking by drinking coffee, which is borderline insane.”
The studies complement work that has been done on coffee and mortality, he said, and it has been reasonably documented that coffee drinkers have a lower risk of death.
With all observations from previous studies, however, it’s difficult to exclude the possibility that coffee drinkers are just healthier to begin with, Gunter said.
People who avoid coffee, particularly in places like the US and Europe where drinking the beverage is very common, may do so because they have health problems. Their higher mortality rate could be a result of them being less healthy to begin with.
“I think that the solid conclusion is that if you’re a coffee drinker, keep drinking your coffee and be happy,” Ascherio said. And if you’re not? “I think you can go on drinking your tea or water without a problem.”
Meanwhile, Gunter and Setiawan stand a bit more firmly on coffee as a health benefit.
“The takeaway message would be that drinking a couple cups of coffee a day doesn’t do you any harm, and actually, it might be doing you some good,” he said.
“Moderate coffee consumption can be incorporated into a healthy diet and lifestyle,” Setiawan said. “This studies and the previous studies suggest that for a majority of people, there’s no long term harm from drinking coffee.”
But as you know, the news on coffee has not always been positive. And the argument over the merits of your daily cup of joe dates back centuries. Let’s take a look at the timeline.
1500’s headline: Coffee leads to illegal sex
Legend has it that coffee was discovered by Kaldi, an Ethiopian goatherd, after he caught his suddenly frisky goats eating glossy green leaves and red berries and then tried it for himself. But it was the Arabs who first started coffeehouses, and that’s where coffee got its first black mark.
Patrons of coffeehouses were said to be more likely to gamble and engage in “criminally unorthodox sexual situations,” according to author Ralph Hattox. By 1511 the mayor of Mecca shut them down. He cited medical and religious reasons, saying coffee was an intoxicant and thus prohibited by Islamic law, even though scholars like Mark Pendergrast believe it was more likely a reaction to the unpopular comments about his leadership. The ban didn’t last long, says Pendergrast, adding that coffee became so important in Turkey that “a lack of sufficient coffee provided grounds for a woman to seek a divorce.”
1600’s headline: Coffee cures alcoholism but causes impotence
As the popularity of coffee grew and spread across the continent, the medical community began to extol its benefits. It was especially popular in England as a cure for alcoholism, one of the biggest medical problems of the time; after all, water wasn’t always safe to drink, so most men, women and even children drank the hard stuff.
Local ads such as this one in 1652 by coffee shop owner Pasqua Rosée popularized coffee’s healthy status, claiming coffee could aid digestion, prevent and cure gout and scurvy, help coughs, headaches and stomachaches, even prevent miscarriages.
But in London, women were concerned that their men were becoming impotent, and in 1674 The Women’s Petition Against Coffee asked for the closing of all coffeehouses, saying in part: “We find of late a very sensible Decay of that true Old English Vigour. … Never did Men wear greater Breeches, or carry less in them…”
1700’s headline: Coffee helps you work longer
By 1730, tea had replaced coffee in London as the daily drink of choice. That preference continued in the colonies until 1773, when the famous Boston Tea Party made it unpatriotic to drink tea. Coffeehouses popped up everywhere, and the marvelous stimulant qualities of the brew were said to contribute to the ability of the colonists to work longer hours.
1800’s headline: Coffee will make you go blind. Have a cup of hot wheat-bran drink instead
In the mid-1800s America was at war with itself and one side effect is that coffee supplies ran short. Enter toasted grain-based beverage substitutes such as Kellogg’s “Caramel Coffee” and C.W. Post’s “Postum” (still manufactured). They advertised with anti-coffee tirades to boost sales. C.W. Post’s ads were especially vicious, says Pendergrast, claiming coffee was as bad as morphine, cocaine, nicotine or strychnine and could cause blindness.
1916 headline: Coffee stunts your growth
While inventions and improvements in coffee pots, filters and processing advanced at a quick pace throughout the 1900s, so did medical concerns and negative public beliefs about the benefits of coffee.
Good Housekeeping magazine wrote about how coffee stunts growth. And concerns continued to grow about coffee’s impact on common aliments of the era, such as nervousness, heart palpitations, indigestion and insomnia.
1927 headline: Coffee will give you bad grades, kids
In Science Magazine, on September 2, 1927, 80,000 elementary and junior high kids were asked about their coffee drinking habits. Researchers found the “startling” fact that most of them drank more than a cup of coffee a day, which was then compared to scholarship with mostly negative results.
1970’s and ’80’s headline: Coffee is as serious as a heart attack
A 1973 study in the New England Journal of Medicine of more than 12,000 patients found drinking one to five cups of coffee a day increased risk of heart attacks by 60% while drinking six or more cups a day doubled that risk to 120%.
Another New England Journal of Medicine study, in 1978, found a short-term rise in blood pressure after three cups of coffee. Authors called for further research into caffeine and hypertension.
A 38-year study by the Johns Hopkins Medical School of more than a 1,000 medical students found in 1985 that those who drank five or more cups of coffee a day were 2.8 times as likely to develop heart problems compared to those who don’t consume coffee. But the study only asked questions every five years, and didn’t isolate smoking behavior or many other negative behaviors that tend to go along with coffee, such as doughnuts. Or “Doooonuts,” if you’re Homer Simpson.
Millennium headline: Coffee goes meta
Now begins the era of the meta-analysis, where researchers look at hundreds of studies and apply scientific principles to find those that do the best job of randomizing and controlling for compounding factors, such as smoking, obesity, lack of exercise and many other lifestyles issues. That means that a specific study, which may or may not meet certain standards, can’t “tip the balance” one way or another. We take a look at some of the years. The results for coffee? Mostly good.
2001 headline: Coffee increases risk of urinary tract cancer
But first, a negative: A 2001 study found a 20% increase in the risk of urinary tract cancer risk for coffee drinkers, but not tea drinkers. That finding was repeated in a 2015 meta-analysis. So, if this is a risk factor in your family history, you might want to switch to tea.
2007 headline: Coffee decreases risk of liver cancer
Some of these data analyses found preventive benefits for cancer from drinking coffee, such as this one, which showed drinking two cups of black coffee a day could reduce the risk of liver cancer by 43%. Those findings were replicated in 2013 in two other studies.
2010 headline: Coffee and lung disease go together like coffee and smoking
A meta-analysis found a correlation between coffee consumption and lung disease, but the study found it impossible to completely eliminate the confounding effects of smoking.
2011 headline: Coffee reduces risk of stroke and prostate cancer
A meta-analysis of 11 studies on the link between stroke risk and coffee consumption between 1966 and 2011, with nearly a half a million participants, found no negative connection. In fact, there was a small benefit in moderate consumption, which is considered to be three to five cups of black coffee a day. Another meta-analysis of studies between 2001 and 2011 found four or more cups a day had a preventive effect on the risk of stroke.
As for prostate cancer, this 2011 study followed nearly 59,000 men from 1986 to 2006 and found drinking coffee to be highly associated with lower risk for the lethal form of the disease.
2012 headline: Coffee lowers risk of heart failure
More meta-analysis of studies on heart failure found four cups a day provided the lowest risk for heart failure, and you had to drink a whopping 10 cups a day to get a bad association.
2013 headline: Coffee lowers risk of heart disease and helps you live longer
For general heart disease a meta-analysis of 36 studies with more than 1.2 million participants found moderate coffee drinking seemed to be associated with a low risk for heart disease; plus, there wasn’t a higher risk among those who drank more than five cups a day.
How about coffee’s effects on your overall risk of death? One analysis of 20 studies, and another that included 17 studies, both of which included more than a million people, found drinking coffee reduced your total mortality risk slightly.
2015 headline: Coffee is practically a health food
As a sign of the times, the U.S. Department of Agriculture now agrees that “coffee can be incorporated into a healthy lifestyle,” especially if you stay within three to five cups a day (a maximum of 400 mg of caffeine), and avoid fattening cream and sugar. You can read their analysis of the latest data on everything from diabetes to chronic disease here.
2017 headline: Yes, coffee still leads to a longer life
The largest study to date on coffee and mortality surveyed 520,000 people in 10 European countries and found that regularly drinking coffee could significantly lower the risk of death.
Another study with a focus on non-white populations and had similar findings. That study surveyed 185,000 African-Americans, Native Americans, Hawaiians, Japanese-Americans, Latinos and whites. The varying lifestyles and dietary habits of the people observed in both studies led the authors to believe that coffee’s impact on longevity doesn’t have to do with how its prepared or how people drink it — it has to do with the beverage’s biological effect on the body.
But stay tuned. There’s sure to be another meta-study, and another opinion. We’ll keep you updated.
