Why Coffee Is Good For You—If You Drink It In The Morning

I love a good morning cup of coffee, as do most medical workers that I know. One of my physician colleagues once quipped, “If our CT scanner goes down, it would be a problem; if the radiology department coffee machine goes down, it would be disaster.”

Two recent research papers support that idea that regular coffee consumption not only feels good but can also be good for one’s health.

Professor Dr. Lu Qi and colleagues at Tulane University recently studied the health effects of coffee drinking for 40,725 adults between 1999 and 2018. After accounting for factors such as age, gender, and pre-existing health conditions, they found two dramatic results. Morning coffee drinkers were 31% less likely to die of cardiovascular disease and 16% less likely to die of any cause compared to the non-coffee drinkers. Furthermore, the time of day people drank coffee made a difference. Those who drank coffee in the morning experienced these health benefits, whereas the “all day” coffee drinkers did not.

The researchers weren’t completely sure why drinking coffee in the morning was a crucial factor. But they surmised, “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.”

How much coffee did someone need to drink? The authors noted that the health benefits occurred with both moderate morning consumption (1-3 cups) and heavy consumption (greater than 3 cups).

The exact biochemical mechanism of the health effects is still unknown, but the researchers believe that “a large portion of coffee’s health benefits are achieved through the anti-inflammatory effects of the bioactive substances it contains.”

Another recent research paper by Xujia Lu and colleagues supports the idea that coffee’s health effects are due not just to the caffeine, but also caffeine’s effects on other metabolic products.

These researchers studied 200,000 coffee and tea drinkers in the UK Biobank database between 2006 and 2010. For roughly half of them (100,000), they also had “metabolomic data”—namely, data on various circulating metabolites in their bloodstreams. Although the full paper may not be available to all readers, Dr. F. Perry Wilson of the Yale School of Medicine has a nice summary of the results.

Dr. Wilson observes, “What you see here is a fairly profound effect that coffee, tea, or caffeine intake has on metabolites of VLDL—bad cholesterol. The beverages lower it, and, of course, higher levels lead to cardiovascular disease. This means that this is a potential causal pathway from coffee intake to heart protection.”

Similarly, coffee appears to lower one’s level of saturated fatty acids, which is also associated with heart disease. As in the Tulane study, the “sweet spot for daily consumption can be found around 3 cups of coffee or tea (or 250 mg of caffeine).”

These new papers appear to confirm prior research linking coffee with decreased cardiovascular disease (CVD) risk. A 2013 meta-analysis of 36 studies published between 1966 and 2013 concluded that, “Moderate coffee consumption was inversely significantly associated with CVD risk, with the lowest CVD risk at 3 to 5 cups per day, and heavy coffee consumption was not associated with elevated CVD risk.”

It is important to note that these are observational studies. As always, correlation does not imply causation. We do not yet fully understand the underlying biochemical mechanisms. But we are getting closer to working out some important details about how coffee helps improve health, how much to drink, and when to drink it. I’ll gladly raise my cup to that.