Coffee drinkers benefit from a health boost – but only if they do it in the morning

People who get their coffee shot in the morning reap benefits not seen in those who have a shot later in the day, according to the first major study into the health benefits of the drink at different times.

Analysis of the coffee consumption of more than 40,000 adults found that morning coffee drinkers were 16% less likely to die from any cause and 31% less likely to die from cardiovascular disease over a ten-year follow-up period. years than those who did not.

But the heart health benefits seemed to disappear in people who drank coffee all day, the researchers found, with medical data showing no significant reduction in mortality among people who drank coffee all day compared to those who avoided coffee.

“It’s not just whether you drink coffee or how much you drink, but the time of day you drink coffee is also important,” says Prof. Lu Qi, an expert in nutrition and epidemiology at Tulane University in New Orleans. “We don’t normally advise on timing in our nutritional guidance, but we may need to think about this in the future.”

The study was based on the dietary habits of 40,725 adults – including the amount of coffee they consumed and when they drank it – who took part in the US National Health and Nutrition Examination Survey between 1999 and 2018. About 36% were morning coffee drinkers, while 16% drank coffee later in the day.

According to the study, morning coffee drinkers had a lower risk of death, whether they were moderate drinkers of two to three cups a day, or heavy drinkers who consumed more. The health benefit was smaller for those who drank just one cup in the morning. Risks were assessed by analyzing participants’ medical records for nine to 10 years after they enrolled in the study.

The results, published in the European Heart Journalwere verified in a smaller group of 1,463 people who completed detailed one-week food and drink diaries.

The research suggests that a morning dose of coffee is better for the heart than an evening dose, but does not explain why. One possible explanation is that drinking coffee later in the day can disrupt circadian rhythms and levels of hormones such as melatonin. This in turn affects sleep, inflammation and blood pressure, all of which can harm heart health.

In one accompanying editorialProfessor Thomas Lüscher, a cardiologist at Royal Brompton and Harefield hospitals in London, notes that many people who drink all day sleep poorly, adding that coffee appears to suppress melatonin, a hormone important for inducing sleep in the brain.

The effects are largely caused by caffeine, but coffee contains hundreds of other bioactive compounds that affect our physiology. The researchers say that some substances in the blood that cause inflammation often peak in the morning and can be counteracted by anti-inflammatory substances in a morning coffee. “This statement applies to both caffeinated and decaffeinated coffee,” they write.

The latest work builds on a 2022 British Biobank survey which showed that people who drank up to three cups of coffee a day had healthier hearts than those who did not. The NHS advises against drinking more than four cups a day as large amounts can increase blood pressure. Pregnant women should consume no more than 200 mg of caffeine per day to avoid a greater risk of low birth weight and miscarriage. A mug of filter coffee contains approximately 140 mg.

“On the whole, we must accept the now substantial evidence that drinking coffee, especially in the morning hours, is probably healthy,” Lüscher writes. “So drink your coffee, but do it in the morning!”