Kidney response to the spectrum of diet-induced acid stress

Abstract

Chronic ingestion of the acid (H+)-producing diets that are typical of developed societies appears to pose a long-term threat to kidney health. Mechanisms employed by kidneys to excrete this high dietary H+load appear to cause long-term kidney injury when deployed over many years. In addition, cumulative urine H+excretion is less than the cumulative increment in dietary H+consistent with H+retention. This H+retention associated with the described high dietary H+worsens as the glomerular filtration rate (GFR) declines which further exacerbates kidney injury. Modest H+retention does not measurably change plasma acid–base parameters but, nevertheless, causes kidney injury and might contribute to progressive nephropathy. Current clinical methods do not detect H+retention in its early stages but the condition manifests as metabolic acidosis as it worsens, with progressive decline of the glomerular filtration rate. We discuss this spectrum of H+injury, which we characterize as “H+stress”, and the emerging evidence that high dietary H+constitutes a threat to long-term kidney health.