E500(ii) – sodium bicarbonate

E500(ii) denotes sodium bicarbonate (NaHCO₃), an alkaline food additive used primarily as a chemical leavening base, pH regulator/acidity corrector, anti-caking agent, and component of effervescent systems. In the presence of food acids or heat it releases CO₂, driving aeration and influencing color and texture.

Caloric value (dry product, 100 g)
Approximately 0 kcal per 100 g (inorganic; no metabolizable energy; used at low, application-dependent levels).

Key constituents
High-purity sodium bicarbonate (NaHCO₃).
Solution species in acid–base equilibrium: Na⁺, HCO₃⁻, and CO₃²⁻.
Food-grade traces (e.g., NaCl, Na₂SO₄), very low acid-insoluble matter, heavy metals below limits.
Low residual moisture; engineered particle size for flow and dissolution.

Production process
Solvay route: brine saturated with NH₃ and CO₂ precipitates NaHCO₃ → washing → low-temperature drying (to avoid thermal decomposition) → milling/classification.
From soda ash: carbonation of Na₂CO₃ solutions with CO₂ → filtration, drying, finishing.
Natural route: extraction/purification of trona/nahcolite with conversion to food-grade NaHCO₃.
Food-grade finishing includes purity/alkalinity assays, loss on drying, insolubles, metals, microbiology, and barrier packaging under GMP/HACCP with defined CCPs.

Technological and sensory properties
Chemical leavening: with acids (cream of tartar, MCP, lactates, etc.) NaHCO₃ releases CO₂; on baking, part thermally decomposes to Na₂CO₃ + CO₂ + H₂O.
Effect on pH and color: alkalinity boosts Maillard browning, increases cookie spread, and tempers acidic notes.
Alkaline residue: excess base or mismatched acid NV leaves Na₂CO₃, causing soapy/alkaline aftertaste.
Secondary roles: anti-caking in dry mixes; effervescence in foods and beverages; acidity control in sauces and controlled caramelization.

Food applications
Cakes, muffins, cookies, pancakes; crackers and wafers; bagels/pretzels (with alkaline baths); effervescent beverages; cocoa processed in alkaline systems (more commonly with K₂CO₃). Typical bakery use: ~0.3–1.0% on flour, paired with acids chosen for suitable NV and release profile.

Nutrition and health
Adds dietary sodium without energy. Formulations should manage total Na⁺ load for sodium-sensitive consumers. Non-culinary “antacid” use is outside technological food use and should not be inferred without professional guidance.

Quality and specification themes
Assay to NaHCO₃ spec; low loss on drying; neutral odor/flavor.
Consistent particle size and bulk density for repeatable dosing; very low insolubles.
Compliance with contaminant limits; full traceability; production under GMP/HACCP.

Storage and shelf life
Store cool, dry, and well sealed; control ambient RH.
Avoid moisture and acids to prevent caking and premature reaction (loss of leavening power). In CO₂/moist air, surface sesquicarbonate may form.
Apply FIFO rotation.

Safety and handling
Generally safe at food-use levels; concentrated solutions can irritate eyes/skin—use appropriate PPE. Segregate from strong acids and incompatible materials.

Troubleshooting
Alkaline/soapy aftertaste: excess NaHCO₃ or insufficient acid (NV mismatch) → reduce base/increase acid or choose thermal-release acids.
Poor rise/large, coarse bubbles: moisture uptake or unsuitable particle size → improve packaging, select calibrated cuts; verify freshness of acidic leaveners.
Excessive browning/bitterness: pH too high or overbake → reduce base and retune bake profile.
Caking in dry mixes: high RH → enhance barrier and include secondary desiccants.

Sustainability and supply chain
The Solvay route is energy/brine intensive; natural routes reduce reagents but have mining impacts. Environmental performance improves via efficient energy use, recyclable packaging, waste minimization, and effluent control against BOD/COD targets.

Cosmetic (INCI) functions
Listed as INCI “Sodium Bicarbonate.” Primary roles: pH adjuster/buffering agent; deodorant (neutralizes acidic odorants); mild abrasive/polishing agent (toothpastes, scrubs); bulking agent in powders; cleansing aid.

Conclusion
E500(ii) is a highly versatile pH regulator and leavening base. Performance hinges on correct pairing with acids (appropriate NV), moisture and particle-size management, and a suitable thermal profile—delivering volume, texture, and color without alkaline off-notes.

Mini-glossary
pH — Measure of acidity/alkalinity; governs flavor, Maillard reactions, and leavening behavior.
CO₂ — Carbon dioxide; gas released by acid–base reaction or thermal decomposition during baking.
NV — Neutralization value; indicates how much base an acid neutralizes (and vice versa) in leavening systems.
Na⁺ — Sodium ion; contributes to total dietary sodium.
RH — Relative humidity; higher RH promotes caking and activity loss.
MCP — Monocalcium phosphate; common fast-acting leavening acid used with NaHCO₃.
INCI — International Nomenclature of Cosmetic Ingredients; standardized names/functions for cosmetic ingredients.
GMP — Good Manufacturing Practice; hygiene/process controls ensuring consistency, traceability, and quality.
HACCP — Hazard Analysis and Critical Control Points; preventive food-safety system with defined CCPs.
CCP — Critical control point; a step where control prevents, eliminates, or reduces a food-safety hazard.
FIFO — First in, first out; inventory rotation principle—use older lots first.
BOD/COD — Biochemical/Chemical oxygen demand; indicators of organic load in effluents and potential environmental impact.

Sodium bicarbonate studies

• Molecular Formula:   NaHCO₃    or   CHNaO₃
• Molecular Weight: 84.006 g/mol
• CAS: 144-55-8  199723-76-7  151127-72-9  196216-68-9  246180-97-2  172672-17-2  1182403-48-0  276253-15-7
• UNII: 8MDF5V39QO
• EC Number: 205-633-8
• PubChem Substance ID 329824559
• MDL number MFCD00003528
• Beilstein Registry Number 4153970

• Baking soda
• Sodium hydrogencarbonate
• Sodium acid carbonate
• Bicarbonate of soda
• Carbonic acid monosodium salt
• Neut
• Col-evac
• Sel De vichy
• Monosodium carbonate
• Natrium bicarbonicum
• Monosodium hydrogen carbonate
• Sodium hydrocarbonate
• Natron
• Natriumhydrogenkarbonat
• sodiumbicarbonate

References__________________________________________________________________________

Serpa Neto A, Fujii T, El-Khawas K, Udy A, Bellomo R. Sodium bicarbonate therapy for metabolic acidosis in critically ill patients: a survey of Australian and New Zealand intensive care clinicians. Crit Care Resusc. 2020 Sep;22(3):275-280. doi: 10.1016/S1441-2772(23)00397-6. 

Abstract. Objective: To help shape the design of a future double blind placebo-controlled randomised clinical trial of bicarbonate therapy for metabolic acidosis, based on opinions of intensive care clinicians in Australia and New Zealand. Design: An online survey was designed, piloted and distributed electronically to members of the Australian and New Zealand Intensive Care Society Clinical Trials Group (ANZICS CTG) mailing list. The survey sought to collect information about choice of placebo, method of bicarbonate administration, and acid-base monitoring. Main outcome measures: Responses to six questions in the following domains were sought: 1) solution to be used as placebo; 2) method of administration; 3) target of the intervention; 4) timing of arterial blood gases to monitor the intervention; 5) duration of therapy; and 6) rate of bolus therapy (if selected as the best option). Results: One in every eight ANZICS CTG members completed the survey (118/880, 13.4%). Compound sodium lactate was the preferred solution for placebo (54/118, 45.8%), and continuous infusion of bicarbonate (80/118, 67.8%) was the most frequently selected method of administration. A pH > 7.30 was the preferred target (50/118, 42.4%), while monitoring with arterial blood gas analysis every 2 hours until the target is reached and then every 4 hours was the most favoured option (40/118, 33.9%). The preferred duration of therapy was until the target is achieved (53/118, 44.9%). Conclusions: This survey offers important insights into the preferences of Australian and New Zealand clinicians in regards to any future randomised controlled trial of bicarbonate therapy for metabolic acidosis in the critically ill.

Loomba RS, Abdulkarim M, Bronicki RA, Villarreal EG, Flores S. Impact of sodium bicarbonate therapy on hemodynamic parameters in infants: a meta-analysis. J Matern Fetal Neonatal Med. 2022 Jun;35(12):2324-2330. doi: 10.1080/14767058.2020.1786051.

Abstract. Objective: Sodium bicarbonate is a frequently used electrolyte for the acute treatment of metabolic acidosis in critically ill patients. We performed a systematic review and meta-analysis to determine the effect of sodium bicarbonate on hemodynamics, gas exchange and oximetry in critically children. Methods: A systematic review of published manuscripts was conducted to identify studies of children who received sodium bicarbonate as part of the treatment for metabolic acidosis. A meta-analysis was then conducted to determine the impact of sodium bicarbonate on hemodynamics, gas exchange and oximetry. The following parameters were captured: base deficit, heart rate, mean arterial pressure, blood concentration of carbon dioxide, blood concentration of hydrogen ion, and pulse oximetry. Results: A total of six studies with 341 patients were included in the analyses. All included studies were completed in critically ill infants with a mean age of 1.1 months. The mean dose of sodium bicarbonate was 1.7 meq/kg with a mean time of 67 min prior to repeat hemodynamics being collected after sodium bicarbonate administration. Base deficit significantly improved with a decrease of 2.80 (p = .001) and the partial pressure of carbon dioxide significantly decreased by a mean of -1.65 mmHg (p = .010). There was no change in heart rate, blood pressure, pH, partial pressure of oxygen, or saturation by pulse oximetry. Conclusion: Sodium bicarbonate has a statistically significant but not clinically significant impact on partial pressure of carbon dioxide and base deficit 60 min after sodium bicarbonate administration in critically ill infants. There is no difference noted in pH, partial pressure of oxygen, or saturation by pulse oximetry.

Zeiler FA, Sader N, West M, Gillman LM. Sodium Bicarbonate for Control of ICP: A Systematic Review. J Neurosurg Anesthesiol. 2018 Jan;30(1):2-9. doi: 10.1097/ANA.0000000000000373.

Abstract. Objective: Our goal was to perform a systematic review of the literature on the use of intravenous sodium bicarbonate for intracranial pressure (ICP) reduction in patients with neurologic illness. Methods: Data sources: articles from MEDLINE, BIOSIS, EMBASE, Global Health, Scopus, Cochrane Library, the International Clinical Trials Registry Platform (inception to April 2015), reference lists of relevant articles, and gray literature were searched. Data extraction: 2 reviewers independently extracted data including population characteristics and treatment characteristics. The strength of evidence was adjudicated using both the Oxford and Grading of Recommendation Assessment Development and Education methodology. Results: Our search strategy produced a total 559 citations. Three original articles were included in the review. There were 2 prospective studies, 1 randomized control trial and 1 single arm, and 1 retrospective case report.Across all studies there were a total of 19 patients studied, with 31 episodes of elevated ICP being treated. Twenty-one of those episodes were treated with sodium bicarbonate infusion, with the remaining 10 treated with hypertonic saline in a control model. All elevated ICP episodes treated with sodium bicarbonate solution demonstrated a significant drop in ICP, without an elevation of serum partial pressure of carbon dioxide. No significant complications were described. Conclusions: There currently exists Oxford level 4, Grading of Recommendation Assessment Development and Education D evidence to support an ICP reduction effect with intravenous sodium bicarbonate in TBI. No comments on its impact in other neuropathologic states, or on patient outcomes, can be made at this time.

Grgic J, Rodriguez RF, Garofolini A, Saunders B, Bishop DJ, Schoenfeld BJ, Pedisic Z. Effects of Sodium Bicarbonate Supplementation on Muscular Strength and Endurance: A Systematic Review and Meta-analysis. Sports Med. 2020 Jul;50(7):1361-1375. doi: 10.1007/s40279-020-01275-y. 

Abstract. Background: The effects of sodium bicarbonate on muscular strength and muscular endurance are commonly acknowledged as unclear due to the contrasting evidence on the topic. Objective: To conduct a systematic review and meta-analysis of studies exploring the acute effects of sodium bicarbonate supplementation on muscular strength and endurance. Methods: A search for studies was performed using five databases. Meta-analyses of standardized mean differences (SMDs) were performed using a random-effects model to determine the effects of sodium bicarbonate supplementation on muscular strength (assessed by changes in peak force [N], peak torque [N m], or maximum load lifted [kg]) and muscular endurance (assessed by changes in the number of repetitions performed, isokinetic total work, or time to maintain isometric force production). Subgroup meta-analyses were conducted for the muscular endurance of small vs. large muscle groups and muscular strength tested in a rested vs. fatigued state. A random-effects meta-regression analysis was used to explore possible trends in the effects of: (a) timing of sodium bicarbonate ingestion; and (b) acute increase in blood bicarbonate concentration (from baseline to pre-exercise), on muscular endurance and muscular strength. Results: Thirteen studies explored the effects of sodium bicarbonate on muscular endurance and 11 on muscular strength. Sodium bicarbonate supplementation was found to be ergogenic for muscular endurance (SMD = 0.37; 95% confidence interval [CI]: 0.15, 0.59; p = 0.001). The performance-enhancing effects of sodium bicarbonate were significant for both small (SMD = 0.31; 95% CI: 0.04, 0.59; p = 0.025) and large muscle groups (SMD = 0.40; 95% CI: 0.13, 0.66; p = 0.003). Sodium bicarbonate ingestion was not found to enhance muscular strength (SMD = - 0.03; 95% CI: - 0.18, 0.12; p = 0.725). No significant effects were found regardless of whether the testing was carried out in a rested (SMD = 0.02; 95% CI: - 0.09, 0.13; p = 0.694) or fatigued (SMD = - 0.16; 95% CI: - 0.59, 0.28; p = 0.483) state. No significant linear trends in the effects of timing of sodium bicarbonate ingestion or acute increase in blood bicarbonate concentrations on muscular endurance or muscular strength were found. Conclusions: Overall, sodium bicarbonate supplementation acutely improves muscular endurance of small and large muscle groups, but no significant ergogenic effect on muscular strength was found.

Calvo JL, Xu H, Mon-López D, Pareja-Galeano H, Jiménez SL. Effect of sodium bicarbonate contribution on energy metabolism during exercise: a systematic review and meta-analysis. J Int Soc Sports Nutr. 2021 Feb 5;18(1):11. doi: 10.1186/s12970-021-00410-y.

Abstract. Background: The effects of sodium bicarbonate (NaHCO3) on anaerobic and aerobic capacity are commonly acknowledged as unclear due to the contrasting evidence thus, the present study analyzes the contribution of NaHCO3 to energy metabolism during exercise. Methods: Following a search through five databases, 17 studies were found to meet the inclusion criteria. Meta-analyses of standardized mean differences (SMDs) were performed using a random-effects model to determine the effects of NaHCO3 supplementation on energy metabolism. Subgroup meta-analyses were conducted for the anaerobic-based exercise (assessed by changes in pH, bicarbonate ion [HCO3-], base excess [BE] and blood lactate [BLa]) vs. aerobic-based exercise (assessed by changes in oxygen uptake [VO2], carbon dioxide production [VCO2], partial pressure of oxygen [PO2] and partial pressure of carbon dioxide [PCO2]). Results: The meta-analysis indicated that NaHCO3 ingestion improves pH (SMD = 1.38, 95% CI: 0.97 to 1.79, P < 0.001; I2 = 69%), HCO3- (SMD = 1.63, 95% CI: 1.10 to 2.17, P < 0.001; I2 = 80%), BE (SMD = 1.67, 95% CI: 1.16 to 2.19, P < 0.001, I2 = 77%), BLa (SMD = 0.72, 95% CI: 0.34 to 1.11, P < 0.001, I2 = 68%) and PCO2 (SMD = 0.51, 95% CI: 0.13 to 0.90, P = 0.009, I2 = 0%) but there were no differences between VO2, VCO2 and PO2 compared with the placebo condition. Conclusions: This meta-analysis has found that the anaerobic metabolism system (AnMS), especially the glycolytic but not the oxidative system during exercise is affected by ingestion of NaHCO3. The ideal way is to ingest it is in a gelatin capsule in the acute mode and to use a dose of 0.3 g•kg- 1 body mass of NaHCO3 90 min before the exercise in which energy is supplied by the glycolytic system.

Aschner JL, Poland RL. Sodium bicarbonate: basically useless therapy. Pediatrics. 2008 Oct;122(4):831-5. doi: 10.1542/peds.2007-2400.

Abstract. Common clinical practices often are unsupported by experimental evidence. One example is the administration of sodium bicarbonate to neonates. Despite a long history of widespread use, objective evidence that administration of sodium bicarbonate improves outcomes for patients in cardiopulmonary arrest or with metabolic acidosis is lacking. Indeed, there is evidence that this therapy is detrimental. This review examines the history of sodium bicarbonate use in neonatology and the evidence that refutes the clinical practice of administering sodium bicarbonate during cardiopulmonary resuscitation or to treat metabolic acidosis in the NICU.

Jaber S, Paugam C, Futier E, Lefrant JY, Lasocki S, Lescot T, Pottecher J, Demoule A, Ferrandière M, Asehnoune K, Dellamonica J, Velly L, Abback PS, de Jong A, Brunot V, Belafia F, Roquilly A, Chanques G, Muller L, Constantin JM, Bertet H, Klouche K, Molinari N, Jung B; BICAR-ICU Study Group. Sodium bicarbonate therapy for patients with severe metabolic acidaemia in the intensive care unit (BICAR-ICU): a multicentre, open-label, randomised controlled, phase 3 trial. Lancet. 2018 Jul 7;392(10141):31-40. doi: 10.1016/S0140-6736(18)31080-8. Epub 2018 Jun 14. Erratum in: Lancet. 2018 Dec 8;392(10163):2440. doi: 10.1016/S0140-6736(18)33040-X. 

Wardi G, Holgren S, Gupta A, Sobel J, Birch A, Pearce A, Malhotra A, Tainter C. A Review of Bicarbonate Use in Common Clinical Scenarios. J Emerg Med. 2023 Aug;65(2):e71-e80. doi: 10.1016/j.jemermed.2023.04.012. Epub 2023 Apr 21. PMID: 37442665; PMCID: PMC10530341.

Grgic J, Pedisic Z, Saunders B, Artioli GG, Schoenfeld BJ, McKenna MJ, Bishop DJ, Kreider RB, Stout JR, Kalman DS, Arent SM, VanDusseldorp TA, Lopez HL, Ziegenfuss TN, Burke LM, Antonio J, Campbell BI. International Society of Sports Nutrition position stand: sodium bicarbonate and exercise performance. J Int Soc Sports Nutr. 2021 Sep 9;18(1):61. doi: 10.1186/s12970-021-00458-w. PMID: 34503527; PMCID: PMC8427947.