Well, besides the obvious caffeine-induced boost to energy, mood, and concentration. In honor of National Coffee Day here in the U.S., I present a multitude of scientific research (courtesy of the New York Times) that finds coffee to not only be safer to drink than once widely assumed, but even downright beneficial.
First, an important caveat: these studies are referring to black coffee, e.g. not the high-calorie, sugar-infused beverages that have comparatively little coffee in them; a coffee drink loaded with sweets is not going to be as healthy as the purer stuff, for obvious reasons. So by no means come away believing that a latte or caramel mocha is beneficial to your health (not that most people think that anyway).
With all that said, here is some encouraging news for fellow coffee lovers concerned about their habit.
Years earlier, a meta-analysis — a study of studies, in which data are pooled and analyzed together — was published looking at how coffee consumption might be associated with stroke. Eleven studies were found, including almost 480,000 participants. As with the prior studies, consumption of two to six cups of coffee a day was associated with a lower risk of disease, compared with those who drank none. Another meta-analysis published a year later confirmed these findings.
Rounding out concerns about the effect of coffee on your heart, another meta-analysis examined how drinking coffee might be associated with heart failure. Again, moderate consumption was associated with a lower risk, with the lowest risk among those who consumed four servings a day. Consumption had to get up to about 10 cups a day before any bad associations were seen.
To be sure, no one is advising that coffee be consumed regularly like a nutritional supplement; this simply proves that moderate amounts of it (and of caffeine specifically) is innocuous if not directly beneficially (setting aside certain pre-existing health conditions of course).
These benefit go well beyond cardiovascular health, too.
A meta-analysis published in 2007 found that increasing coffee consumption by two cups a day was associated with a lower relative risk of liver cancer by more than 40 percent. Two more recent studies confirmed these findings. Results from meta-analyses looking at prostate cancer found that in the higher-quality studies, coffee consumption was not associated with negative outcomes.
The same holds true for breast cancer, where associations were statistically not significant. It’s true that the data on lung cancer shows an increased risk for more coffee consumed, but that’s only among people who smoke. Drinking coffee may be protective in those who don’t. Regardless, the authors of that study hedge their results and warn that they should be interpreted with caution because of the confounding (and most likely overwhelming) effects of smoking.
A study looking at all cancers suggested that it might be associated with reduced overall cancer incidence and that the more you drank, the more protection was seen.
Drinking coffee is associated with better laboratory values in those at risk for liver disease. In patients who already have liver disease, it’s associated with a decreased progression to cirrhosis. In patients who already have cirrhosis, it’s associated with a lower risk of death and a lower risk of developing liver cancer. It’s associated with improved responses to antiviral therapy in patients with hepatitis C and better outcomes in patients with nonalcoholic fatty liver disease. The authors of the systematic review argue that daily coffee consumption should be encouraged in patients with chronic liver disease.
The most recent meta-analyses on neurological disorders found that coffee intake was associated with lower risks of Parkinson’s disease, lower cognitive decline and a potential protective effect against Alzheimer’s disease (but certainly no harm).
A systematic review published in 2005 found that regular coffee consumption was associated with a significantly reduced risk of developing Type 2 diabetes, with the lowest relative risks (about a third reduction) seen in those who drank at least six or seven cups a day. The latest study, published in 2014, used updated data and included 28 studies and more than 1.1 million participants. Again, the more coffee you drank, the less likely you were to have diabetes. This included both caffeinated and decaffeinated coffee.
Is coffee associated with the risk of death from all causes? There have been two meta-analyses published within the last year or so. The first reviewed 20 studies, including almost a million people, and the second included 17 studies containing more than a million people. Both found that drinking coffee was associated with a significantly reduced chance of death. I can’t think of any other product that has this much positive epidemiologic evidence going for it.
In sum, the scientific consensus is overwhelmingly in favor of coffee being, at worst, innocuous to human health (again, not include the fat and sugar many people add to their drink). There is practically no evidence that drinking coffee is bad for you in anyway, but nor is there any evidence that consuming bucketloads of it will significantly boost your health either. These correlative results simply prove that there is no reason to treat coffee as the vice it has long been held up to be. For what it is worth, even the U.S.D.A. has come on board about the safety and benefits of coffee.