A recent study, published in Kidney International Reports, has shown that drinking two to three cups of coffee a day may reduce kidney injury risk by 23 per cent but the finding should not be taken at face value.
“It is a fairly big study and is being looked at with interest as researchers investigated the effects of coffee consumption on acute kidney injury (AKI), when the kidneys lose all or part of their function suddenly. They found that drinking any amount of coffee reduces the risk of acute kidney injury but that 2-3 cups per day is most beneficial. One cannot rule out the effect of personal bias and methodology of data collection in bringing out the vaunted conclusions. Besides, it is just indicative as researchers noted their findings might be the result of bioactive compounds in coffee that improve perfusion and oxygen utilization in the kidneys,” says Dr Sunil Prakash, Senior Director & HOD, Nephrology & Renal Transplantation, BLK Max Super Speciality Hospital, New Delhi.
“We must realise that retrospective data collection has its own problems. Positive conclusions on a popular drink like coffee seek attention of millions on print and electronic media. Hence there is need for more caution in jumping to such a conclusion,” he warns, adding, “Although caffeine increases renal flow, it is also implicated in causing renal stones.”
Dr Prakash cites studies which show decline in GFR (Glomerular Filtration Rate). “If more than two cups of coffee are consumed, then it increased 1.19 fold risk of eGFR (estimating Glomerular Filtration Rate) decline of more than 3 ml/min (Ref- Andres Diaz Lopez et al Scientific reports 11 article no 8719 of 2021). This is opposite of the present study. Besides in India, where tea remains a major beverage, specially for lower middle class and poorer people, a study to directly compare head-to-head advantages and disadvantages of coffee versus tea should be done,” says he.
“In a nutshell I feel coffee in moderation may have a place in AKI reduction, but only when all other dietary and medical factors are properly accounted for,” Dr Prakash says.
The authors of the study were Dr Kalie L Tommerdahl, assistant professor of pediatric endocrinology at the University of Colorado, and Dr Chirag Rohit Parikh, director of the Division of Nephrology at Johns Hopkins University.
Coffee contains many beneficial compounds for health, including caffeine, diterpenes and chlorogenic acid. Although other compounds in coffee are less studied, compounds such as chlorogenic acid and trigonelline are known to reduce generalised inflammation and oxidative stress.