Question explored with the scientific record
Conversation so far
- 1 What is dietary acid , how can I reducecit andxwhy shoukd I?
- 2 How do I estimate my dietary acid load from my diet?
Answered on this page ↓
How do I estimate my dietary acid load from my diet?
The short version: you can estimate your dietary acid load with a simple formula using protein, potassium, magnesium, and phosphorus, but the evidence behind it is thin and mostly from children.
The most common method is the Potential Renal Acid Load (PRAL) formula. It was developed from adult absorption data and tested in a large German study of 720 children and adolescents called the DONALD Study [13]. The formula is: PRAL = 0.4888 × protein (g/day) + 0.0366 × phosphorus (mg/day) − 0.021 × potassium (mg/day) − 0.0263 × magnesium (mg/day) [13]. A positive number means an acid load, a negative number means an alkaline load.
The DONALD study found that PRAL was positive across all age and sex groups, meaning the typical diet produces net acid. Boys over 8 had higher PRAL than girls [13]. The main acid-producing foods were cheese, meat, fish, eggs, and cereal products. The main alkaline foods were fruits, vegetables, and potatoes [13].
But this formula has real limits. It was validated in German children, not in adults or sick populations. It leaves out calcium because absorption varies with growth [13]. The formula assumes adult absorption rates for all nutrients, which may not hold for everyone. And no study in this retrieval tested whether lowering your PRAL score actually improves any health outcome like bone density, kidney function, or muscle mass.
| Nutrient | Multiplier in PRAL formula | Effect on acid load |
|---|---|---|
| Protein | +0.4888 per gram | Increases acid |
| Phosphorus | +0.0366 per mg | Increases acid |
| Potassium | −0.021 per mg | Decreases acid |
| Magnesium | −0.0263 per mg | Decreases acid |
My call: the PRAL formula is a reasonable starting point for estimating dietary acid load, but the evidence base is narrow. It comes from one large pediatric study with no validation against hard outcomes. If you want to reduce your acid load, the practical takeaway is simple: eat more fruits and vegetables and less cheese and meat. You do not need a formula for that. Confidence: low.
Sources examined 14
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Estimated Net Endogenous Acid Production and Serum Bicarbonate in African Americans with Chronic Kidney Disease
This study investigates the relationship between estimated net endogenous acid production (NEAP) and serum bicarbonate levels in African Americans with chronic kidney disease (CKD), finding that higher NEAP is associated with lower serum bicarbonate, particularly in advanced sta…
DOI: 10.2215/cjn.00150111 -
Dietary acid load and chronic kidney disease in elderly adults: Protein and potassium intake
This study investigates the association between dietary acid load, as measured by estimated net endogenous acid production (eNEAP), and chronic kidney disease (CKD) in elderly Koreans, finding that higher eNEAP is linked to increased odds of CKD, while higher potassium intake is…
DOI: 10.1371/journal.pone.0185069 -
Association Between Estimated Net Endogenous Acid Production and Subsequent Decline in Muscle Mass Over Four Years in Ambulatory Older Chinese People in Hong Kong: A Prospective Cohort Study
This prospective cohort study investigates the association between estimated net endogenous acid production (NEAP) and the decline in muscle mass over four years in 3,122 older Chinese adults in Hong Kong, finding that higher NEAP is linked to greater muscle loss.
DOI: 10.1093/gerona/glu215 -
Ammonium and bicarbonate transport in rat outer medullary collecting ducts
This study investigates ammonium and bicarbonate transport in isolated rat outer medullary collecting duct inner stripe (OMCDIS) segments using the isolated perfused tubule technique, revealing spontaneous ammonium secretion and bicarbonate reabsorption, a measured NH3 permeabil…
DOI: 10.1152/ajprenal.1992.262.1.f1 -
Protein degradation and synthesis measured with multiple amino acid tracers in vivo
This in vivo study in eight healthy adults compares whole-body protein turnover measurements using three amino acid tracers (leucine, phenylalanine, and tyrosine) under basal and insulin/amino acid–induced anabolic conditions, revealing that tracer choice yields similar results …
DOI: 10.1152/ajpendo.1996.271.4.E733 -
Kainic Acid Inhibits the Synaptosomal Plasma Membrane Glutamate Carrier and Allows Glutamate Leakage from the Cytoplasm but Does Not Affect Glutamate Exocytosis
Kainic acid inhibits the synaptosomal Na+-glutamate cotransporter, blocking D-aspartate uptake and carrier-mediated glutamate efflux, while unmasking a slow cytoplasmic leak; it does not affect Ca2+-dependent exocytotic glutamate release.
DOI: 10.1111/j.1471-4159.1988.tb02977.x -
Protein and lipid utilization during long-term fasting in emperor penguins
The study quantified how emperor penguins partition energy between proteins and lipids during long-term fasting, showing strong protein sparing (about 4% from protein, 96% from lipids) during the main phase, followed by a progressive rise in protein contribution as lipid stores …
DOI: 10.1152/ajpregu.1988.254.1.r61 -
Acid Base Balance and Electrolyte Therapy
An accessible guide to diagnosing and treating acid-base and electrolyte disorders in cattle using routine serum measurements (Na+, K+, Cl-, TCO2) and bicarbonate-based fluid therapy, illustrated by four case reports and a practical bicarbonate-deficit calculation.
DOI: 10.21423/aabppro19827524 -
Studies on gastric digestion of protein and carbohydrate, gastric secretion and exocrine pancreatic secretion in the growing pig
The study quantitatively characterizes gastric digestion and secretions (gastric and pancreatic) in growing pigs using duodenal re-entrant cannulas to separate digesta from pancreatic juice, comparing semi-purified (diet A) and cereal-based (diet B) diets.
DOI: 10.1079/bjn19830049 -
Gastric antisecretory effect of serotonin: quantitation of release and site of action
This study quantifies endogenous serotonin release from gastric stores and demonstrates that systemic (but not luminal) 5-HT inhibits gastric acid secretion in rats via a portal-circulation–mediated, basolateral action, independent of autonomic nerves, prostaglandins, mucosal ma…
DOI: 10.1152/ajpendo.1996.271.4.E669 -
Production of methanethiol from dimethylsulfoniopropionate in marine surface waters
The study demonstrates that methanethiol (MeSH) is a major and rapidly turning-over product of DMSP degradation in aerobic marine surface waters, with net MeSH yields often comparable to or exceeding DMS yields and modulated by microbial activity and dissolved organic matter.
DOI: 10.1016/0304-4203(96)00006-0 -
Cold water treatment promotes ethylene production and dwarfing in tomato seedlings
Cold water treatment of tomato seedlings elevates endogenous ethylene production, producing dwarfing of the shoots, and the dwarfing is shown to be ethylene-mediated by using ethephon (ethylene donor) and 1-MCP (ethylene perception inhibitor) pretreatments to modulate the respon…
DOI: 10.1016/s0981-9428(03)00020-2 -
Potential renal acid load in the diet of children and adolescents: impact of food groups, age and time trends
Longitudinal analysis of dietary renal acid load (PRAL) in 720 German children and adolescents from the DONALD Study, identifying age and gender differences in PRAL contributions from food groups and showing limited time trends, using three-day dietary records and a PRAL calcula…
DOI: 10.1017/s1368980007000328 -
Relationship of renal ammonia production and potassium homeostasis
This review synthesizes evidence that renal ammonia production (ammoniagenesis) is tightly linked to potassium homeostasis: potassium depletion increases ammonia production and ammonia excretion, while chronic potassium loading decreases it, suggesting a regulatory loop that hel…
DOI: 10.1038/ki.1977.63