Tired of reading about Covid-19? Me too. I will not blog about the novel Coronavirus until there is something new and important to say. (And, no, I do not think that a few serious but very rare allergic reactions fit that description. If they did, we would have to take penicillin and many other important drugs off the market.)
Coffee has a fascinating history. Legend has it that it was discovered by a goat herder in Ethiopia when he noticed that after his goats ate berries from a specific tree, they became so energetic they did not want to sleep at night. From Ethiopia, coffee spread throughout the Arabian peninsula, and coffee houses soon became a staple of social life in the Muslim world. (Based on our travels, this is still true.) European travelers to the Middle East brought back stories of this unusual black beverage, and by the early 17th century, coffee had made its way to Europe. Initially condemned by the clergy as Satanic, coffee got a new lease on life when Pope Clement VIII tasted it, liked it and gave it papal blessing.
While there are numerous chemicals in coffee that lead to differences in aroma, color and taste, the main active ingredient is caffeine. It is caffeine that makes us more energetic and alert (good) and can also make us jittery and unable to sleep (bad). The caffeine in your cup reaches peak levels in your blood some 30 to 60 minutes after you drink it and has a “half-life” of 3 to 5 hours, meaning that some its effect can persist for 10 hours or longer.
In the United States, some 85% of adults consume caffeine daily, most commonly from coffee, but also from tea, chocolate, energy drinks, colas or in tablet form. The estimated average daily consumption of caffeine is 135 mg/day, the amount in about 1.5 8 ounce cups of coffee.
What about health risks and benefits of coffee? The science is less than robust, because most studies are based on comparing differences between people based on their self-reporting of how much coffee they drink. We have, or at least should have, learned that such “observational studies” can suggest possible benefits and harms but cannot prove them. People who drink 2-3 cups of coffee a day may not be like people who do not touch coffee. They may smoke more (or less), exercise more (or less) or may be more (or less) obese. Hence, take everything I say below as hypothesis or conjecture, not Truth.
Caffeine clearly increases alertness, reduces fatigue and reduces reaction time. It improves vigilance in performing tasks that require a long time with minimal stimulation, such as flying aircraft, driving long distances or working on an assembly line. It contributes to pain relief when added to common pain killers such as aspirin or acetaminophen (Tylenol).
Caffeine also delays falling asleep and reduces sleep quality. Particularly at higher doses, it can cause or increase anxiety. These effects vary widely between different individuals. I have friends who drink a strong cup of coffee routinely at bedtime and drop off “like a log.” When I eat dinner out (remember those days?), I will ask the server for a cup of decaf “and your phone number, so I know who to call when I am awake at 3 AM.”
What about coffee’s effects on overall health? While consuming pure caffeine chronically has been shown to modestly elevate blood pressure, coffee does not appear to do this. Unfiltered coffee contains a compound that lowers the “good” cholesterol, HDL. This is not true for instant or filtered coffee, so if you are concerned about your lipids, avoid French press or Turkish coffee. There is no evidence that consuming as much as six cups of coffee daily increase the risk of heart attack or stroke.
There have been isolated reports of severe cardiovascular reactions, including sudden death, in people who took very large quantities of “energy drinks,” particularly when taken for weight loss or prior to gym work-outs.
The effects of coffee on cancer are, if anything, beneficial. Many cancers are less frequent in coffee drinkers, including liver, prostate, endometrial, skin and breast. A study published in November of 2020 found a lower risk of progression of metastatic colon cancer in coffee drinkers. Coffee drinkers also have fewer gallstones and kidney stones. Caffeinated (but not decaf) coffee appears to be protective against the development of Parkinson’s disease.
There is controversy about coffee consumption in pregnancy. A study published in the British Medical Journal claimed that maternal caffeine consumption was associated with increased risk of miscarriage and low birth weight. Both the British and American obstetric societies reviewed the study and disagreed with its recommendation that pregnant women avoid caffeine. The best advice seems to be to limit intake to the equivalent of 2 cups of coffee a day.
Several studies have found an association of drinking 2-5 cups of coffee daily with reduced mortality, and none have shown an increase.
A gentle reminder to older readers: caffeine is a diuretic - it will make you go more.
Bottom line: enjoy your morning Cup of Joe, guilt-free, but don’t overdo it.
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