Kidney Response to the Spectrum of Diet-Induced Acid Stress

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.