‘Drink your coffee, but only in the morning’: What a new study says

It found that morning coffee drinkers were 16% less likely to die of any cause, and 31% less likely to die from cardiovascular disease than those who did not consume the beverage. But medical records showed no significant reduction in mortality for all-day drinkers compared to non-drinkers.

“It’s not just whether you drink coffee or how much you drink, but the time of day when you drink coffee that’s important,” study author Lu Qi, an expert in nutrition and epidemiology at Tulane University in New Orleans, told The Guardian.

The study reported lower mortality risk among morning coffee drinkers, irrespective of how much coffee they drank. In fact, it found that the health benefits associated with coffee were smaller for those who drank only one cup in the morning.

The analysis was based on data collected from 40,275 adults who participated in the US National Health and Nutrition Examination Survey between 1999 and 2018. It was further verified using the smaller Women’s and Men’s Lifestyle Validation Studies (2010-13) which included the seven-day dietary record of 1,463 adults in the US.

Rationale behind findings

Although the study did not explain what led to lower mortality among morning coffee drinkers, other research might provide an answer to this question.

One study published in The Journal of Clinical Sleep and Medicine in 2013 found that caffeine consumption — caffeine being the main stimulant in coffee — even six hours prior to bedtime can have major disruptive effects on sleep, which in turn has deleterious effects on the heart, and overall health.

A more recent study published in 2023 in the journal Sleep Medicine Reviews found that even moderate caffeine consumption less than 8 hours before bed time reduced total sleep time by 45 minutes, and sleep efficiency (the ratio of the time one spends asleep to the total time one spends in bed) by 7%. It also increases sleep onset latency (amount of time it takes to fall asleep after switching off lights) by 9 minutes.

That said, coffee also contains hundreds of other bioactive compounds which too might play a role in its morning benefits. The researchers wrote that some substances in the blood that drive inflammation often peak in the morning, and could be countered by anti-inflammatory compounds in a morning coffee.

Prof Thomas F Lüscher, in an accompanying editorial to the study, referred to the growing body of evidence suggesting that coffee drinking is indeed beneficial to human health. He wrote: “Drink your coffee, but do so in the morning!”