Do coffee drinkers live longer than non-coffee drinkers? Is it, “Wake up and smell the coffee,” or “Don’t wake up at all?” The largest study ever conducted on diet and health put that question to the test, examining the association between coffee drinking and subsequent mortality among hundreds of thousands of older men and women in the United States. Coffee drinkers won, though the effect was modest. 10 to 15% lower risk of death for those drinking six or more cups a day, specifically due to lower risk of dying from heart disease, respiratory disease, stroke, injuries and accidents, diabetes, and infections.

That much coffee was found to increase the death rates of younger people, though—under age 55. Hence, based on this study, it may be appropriate to recommend that you avoid drinking more than four cups a day. But, if you put all the studies together, the bottom line is that coffee consumption is associated with no change or a small reduction in mortality starting around one or two cups a day, for both men and women.

On a cup by cup basis, the risk of dying was 3% lower for each cup of coffee consumed daily, which provides reassurance with respect to the concern that coffee drinking might adversely affect health.

Well, at least, longevity. Healthwise though, a recent population study found no link between coffee consumption and symptoms of GERD, such as heartburn and regurgitation. If you actually stick a tube down people’s throats and measure pH, coffee induces significant acid reflux, whereas tea does not. Is it just because tea has less caffeine? No. If you reduce the caffeine content of coffee down to that of tea, it still causes significantly more acid reflux. Decaf did cause less though, so GERD patients might want to choose decaffeinated, or even better, drink tea.

Coffee intake is also associated with urinary incontinence, and so a decrease in caffeine intake should be discussed with women who have the condition, or men. About two cups of coffee a day worth of caffeine may worsen urinary leakage in men as well.

A 2014 meta-analysis suggested that daily coffee consumption was associated with a slightly increased risk of bone fractures in women, but a decreased risk of fractures in men. Not hip fractures, though. No significant association was found between coffee consumption and the risk of hip fracture, though tea consumption may actually be protective against hip fracture, though it appears to have no apparent relationship with fracture risk in general.

There are certain populations in particular who may want to stay away from caffeine; for example, those with glaucoma, and possibly even those with a family history of glaucoma.

It goes without saying that people who have trouble sleeping might not want to imbibe. Even just a single cup at night can cause a significant deterioration in sleep quality. Then there are case reports, for example, of individuals with epilepsy having fewer seizures after stopping coffee; so, I guess it’s worth a shot.  

We used to think caffeine might increase the risk of an irregular heart rhythm called atrial fibrillation, but that too was based on anecdotal case reports, like this one of a young woman who suffered atrial fibrillation after chocolate intake abuse. But these cases invariably involved the acute ingestion of very large quantities of caffeine. As a result, though, the notion that caffeine ingestion may trigger abnormal heart rhythms had become ”common knowledge,” and this assumption led to changes in medical practice. More recently, however, the pendulum has swung in the opposite direction. Why? Because we actually have data now: caffeine does not increase the risk of atrial fibrillation. And low-dose caffeine, which they define as less than about five cups of coffee a day, may even have a protective effect. Tea consumption also appears to lower cardiovascular disease risk, especially when it comes to stroke. However, given the proliferation of energy drinks that contain massive quantities of caffeine, one might temper any message that suggests caffeine is beneficial. Seems a little patronizing, but it’s no joke. Twelve highly caffeinated energy drinks within a few hours could be lethal.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

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