By Stephen Beech
Coffee in the morning reduces the risk of a heart attack or stroke more than drinking it all day, suggests new research.
People who drink coffee in the morning have a lower risk of dying from cardiovascular disease and are less likely to die young than all-day coffee drinkers, say scientists.
The study, published in the European Heart Journal, involved 40,725 adults taking part in the US National Health and Nutrition Examination Survey (NHANES) between 1999 and 2018.
The participants were asked about all the food and drink they consumed on at least one day, including whether they drank coffee, how much and when.
The study also included a sub-group of 1,463 people who were asked to complete a detailed food and drink diary for a full week.
American researchers were able to link the information with records of deaths and causes of death over a period of up to 10 years.
Study leader Professor Lu Qi, of Tulane University in New Orleans, said: “Research so far suggests that drinking coffee doesn’t raise the risk of cardiovascular disease, and it seems to lower the risk of some chronic diseases, such as type 2 diabetes.
“Given the effects that caffeine has on our bodies, we wanted to see if the time of day when you drink coffee has any impact on heart health.”
Just over a third of people in the study (36%) were morning coffee drinkers, primarily drinking it before midday, while 16% people drank coffee throughout the day. Just under half (48%) were not coffee drinkers.
Compared with people who did not drink coffee, morning coffee drinkers were 16% less likely to die of any cause and 31% less likely to die of cardiovascular disease.
However, there was no reduction in risk for all-day coffee drinkers compared to non-coffee drinkers.
Morning coffee drinkers benefitted from the lower risks whether they were moderate drinkers (two to three cups) or heavy drinkers (more than three cups).
Light morning drinkers – one cup or less – benefitted from a smaller decrease in risk, according to the findings.
Dr. Qi said: “This is the first study testing coffee drinking timing patterns and health outcomes.
“Our findings indicate that 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.
“We don’t typically give advice about timing in our dietary guidance, but perhaps we should be thinking about this in the future.
“This study doesn’t tell us why drinking coffee in the morning reduces the risk of death from cardiovascular disease.
“A possible explanation is that consuming coffee in the afternoon or evening may disrupt circadian rhythms and levels of hormones such as melatonin.
“This, in turn, leads to changes in cardiovascular risk factors such as inflammation and blood pressure.”
He added: “Further studies are needed to validate our findings in other populations, and we need clinical trials to test the potential impact of changing the time of day when people drink coffee.”
Professor Thomas LuÌscher, of Royal Brompton and Harefield Hospitals, welcomed the findings.
In an accompanying editorial, LuÌscher, who was not involved in the research, said: “In the morning hours there is commonly a marked increase in sympathetic activity as we wake up and get out of bed, an effect that fades away during the day and reaches its lowest level during sleep.
“Thus, it is possible, as the authors point out, that coffee drinking in the afternoon or evening disrupts the circadian rhythm of sympathetic activity.
“Indeed, many all-day drinkers suffer from sleep disturbances.
“In this context, it is of interest that coffee seems to suppress melatonin, an important sleep-inducing mediator in the brain.”
He added: “Overall, we must accept the now substantial evidence that coffee drinking, particularly in the morning hours, is likely to be healthy.
“Thus, drink your coffee, but do so in the morning!”
