Chronic Low-Grade Metabolic Acidosis in Normal Adult Humans: Pathophysiology and Consequences

Abstract

Normal adult humans eating modern-day diets have a chronic low-grade metabolic acidosis whose severity is determined in part by the net rate of endogenous acid production (NEAP). NEAP varies mainly with diet composition. The greater the quantity of organic and sulfuric acids produced from metabolism of animal foods, and the lower the amounts of potassium salts metabolizable to bicarbonate, which come mainly from fruits and vegetables, the greater the production rate of acid. It had previously been thought that “healthy” kidneys were capable of excreting any excess acid produced by the body’s metabolism [1]; the authors’ research suggests that the normally occurring slow decline in renal function with age allows the kidneys to merely mitigate the degree of severity of the acidosis, and with increasing age, the steady-state levels of acidity in the body slowly rise [2– 3].