A massive umbrella study published in the British Medical Journal has concluded that moderate coffee intake is generally safe for most of the population. The review examined over 200 meta-studies on the health effects of coffee consumption and concluded that three to five cups a day looks to be the safest maximum volume one should consume.

Late last century, several major scientific studies turned coffee into a bad guy, linking the popular beverage to heart problems and high blood pressure. The popularity of decaffeinated coffee peaked in the 1980s, but at the turn of the century the science started to turn.

The rise of meta-analyses allowed scientists to take the data from scores of prior studies on a single topic and draw more comprehensive conclusions. In regards to coffee, many new studies started to account for more lifestyle factors, such as smoking and obesity. And the results turned the tide on coffee.

In 2017 we have literally hundreds of different coffee consumption studies examining links between the drink and a variety of different health outcomes. We even have scores of meta-studies bringing all this data together. The latest umbrella review is basically the meta-study of meta-studies, gathering data from 218 different meta-analyses that examined over 60 different health outcomes.

Across almost all health outcomes reviewed, coffee consumption was found to either not increase risk or actually decrease risk to negative health outcomes. From diabetes and cirrhosis, to most cancers and cardiovascular disease, coffee consumption was seen to be generally safe with occasional mild benefits.

The ideal intake found by the umbrella review was equal to or less than 400 mg of caffeine per day, or essentially no more than four to five standard cups. The study adjusted for smoking with coffee, and additions such as milk and sugar, all of which reduce any of the safe or beneficial effects of coffee consumption. So no giant mocha lattes with a cigarette on the side folks.

The only two significant population subgroups noted by the study that showed a correlation between coffee consumption and negative effects were pregnant women, and women with high risks of bone fractures. During pregnancy coffee consumption was potentially associated with low birth weight and preterm birth.

The study concludes by suggesting that, as it is primarily based on observational data of a generally low quality, the takeaway is not to start drinking coffee for health reasons, but rather that coffee is most likely entirely safe for the majority of the general population.

The study was published in the British Medical Journal.