Table 1.

Definitions and relationships between terminology used in prior literature

Term	Definition	Relationship to other terms†
Endogenous acid production (EAP)	The sum of acid produced during oxidation of sulfur- containing protein and the generation of organic anions (OA) from neutral foods	EAP = NEAP + GI alkali absorption
Gastrointestinal (GI) alkali absorption	The net addition of alkali as the result of nutrients absorbed in the GI tract.	GI alkali absorption = EAP − NEAP
Net endogenous acid production (NEAP)	The total load of nonvolatile acid added to the body as a result of endogenous acid production and GI absorption.	NEAP = EAP − GI alkali absorption NEAP = PRAL + OA production‡
Potential renal acid load (PRAL)	The contribution of a food or dietary pattern to net endogenous acid production.	PRAL ≈ NEAP − OA production‡
Net acid excretion (NAE)	The total amount of acid excreted by the kidney daily	NAE ≈ NEAP NAE ≈ PRAL + OA production‡

^†all terms represented in mEq

^‡Results from endogenous production of organic anions from neutral foods and is classicially considered diet-independent