High salt diet and caffeine: food for thought

The popularity of coffee and other caffeine-containing beverages in the Western diet undoubtedly draws attention of researchers to the studies of caffeine-mediated effects on human physiology and disease. Another hallmark of the modern diet is high salt consumption, which is associated with cardiovascular complications. A recent research article by Yu et al. targets both topics and is focused on the chronic effects of caffeine consumption on the development of salt-sensitive (SS) hypertension (1). This type of hypertension is widespread, and particularly in hypertensive African American population its prevalence reaches almost 73% (2). This is a nice study targeting identification of sodium channels or transporters affected by caffeine; however, it is not the first one. For instance, Fenton et al. recently reported that caffeine-induced diuresis and natriuresis are independent of phosphorylation or expression of Na+/H+ exchanger isoform 3 (NHE3) in the kidney (3). Nevertheless, this manuscript is very timely and well done. The central hypothesis of the manuscript is that enhanced sodium reabsorption via the epithelial sodium channel (ENaC) that occurs in the distal nephron (4) may be decreased by chronic caffeine intake, and leads to a reduction in systolic blood pressure. This study raises a number of questions that may provoke an exciting discussion in the literature