Ever since coffee was discovered over a millennium back in Ethiopia, pages upon pages have been written about the myriad health effects of caffeine. Being a psychoactive substance, caffeine has been regulated and even banned for multiple reasons ranging from the religious to its effect on “overstimulating the senses’. But talking from a health perspective will restrict to the renal and cardiovascular effects of coffee (the effects of coffee are dose-dependent; 8 oz. cup of coffee has about 100-200mg of caffeine) as diet plays a huge role in the management of chronic kidney disease (CKD).
KIDNEY DISEASE, BLOOD PRESSURE, AND CARDIOVASCULAR EFFECTS
There is some evidence that caffeine can cause momentary increases in blood pressure (up to 10mmHg), especially in people who are not habitual coffee drinkers. However, this effect is enhanced in the elderly, and people who have underlying hypertension.
Given hypertension’s deleterious effects on the kidneys, it would seem plausible that moderating caffeine intake could indirectly have a beneficial effect on the kidneys. However, despite the possibility of these kidney damaging effects of caffeine that would make sense, the evidence has not quite panned out that way. And so, if we look at the aggregate data, consuming the equivalent of 3-4 cups of coffee daily does increase the risk of kidney disease, this applies to the average person. There still are special situations like kids and the elderly where caution needs to be taken given the other cardiovascular and diuretic effects. A similar rider also applies to people who are at risk of forming kidney stones.
My take-home message: if you don’t fit any of the special categories mentioned above, it is probably safe to consume moderate amounts of coffee from a kidney standpoint!
