What is E623?

Complete guide to understanding E623 (Calcium Diglutamate) in your food

The Quick Answer

E623 is calcium diglutamate (calcium di-L-glutamate), the calcium salt of glutamic acid, used as a flavor enhancer to provide the “umami” (savory) taste—functioning as a non-sodium alternative to MSG (E621) that delivers identical flavor-enhancing function while providing calcium and reducing sodium.

It’s a calcium salt version of glutamate, providing the characteristic savory “fifth taste” (umami) by enhancing natural food flavors, used in baked goods, soups, sauces, and processed foods where flavor enhancement with calcium provision is desired.

Most people consuming processed foods, soups, baked goods, and sauces occasionally encounter E623, though it remains largely invisible—functioning as a flavor enhancer with official regulatory approval but facing IDENTICAL cumulative exposure concerns as other glutamates (E620-E625), where 2017 EFSA found exposure EXCEEDS safe levels in vulnerable populations, particularly infants and children.

The Critical Context—E623 Shares All Glutamate Safety Concerns

E623 calcium diglutamate is the calcium salt version of glutamic acid, sharing IDENTICAL safety concerns with all glutamates (E620-E625) documented in the 2017 EFSA re-evaluation: cumulative glutamate exposure EXCEEDS safe levels (ADI of 30 mg/kg bw as glutamic acid) in infants, toddlers, and children, with neurotoxic potential and MSG symptom complex at high doses. Unlike E621 (sodium) and E622 (potassium) versions, E623 provides additional calcium contribution, but this advantage does not mitigate the shared cumulative exposure concerns.

What Exactly Is It?

E623 is calcium diglutamate (calcium di-L-glutamate), also called monocalcium diglutamate, the calcium salt of L-glutamic acid with molecular formula Ca(C₅H₈NO₄)₂ and molecular weight of approximately 332 g/mol (anhydrous form).

Calcium diglutamate is a calcium acid salt of glutamic acid—one of the 20 standard amino acids. When provided as a salt (monosodium glutamate/MSG, monopotassium glutamate, or calcium diglutamate), glutamate functions as a taste enhancer, amplifying the perception of umami (savory) taste. E623 is specifically the CALCIUM salt version, providing the flavor-enhancing function of glutamate while substituting calcium for sodium, delivering both flavor enhancement and nutritional calcium benefit.

Physically, E623 appears as white, practically odorless crystals or crystalline powder. It is freely soluble in water, allowing easy incorporation into aqueous food systems. The compound is heat-stable and maintains flavor-enhancing activity through food processing and storage.

Chemically, E623 functions through the same mechanism as all glutamates: it activates umami taste receptors on the tongue, enhancing perception of natural savory flavors in foods. Upon ingestion, the glutamate is absorbed in the intestine and presystemically metabolized in the gut wall (meaning metabolized before entering systemic circulation). The calcium ions are absorbed and utilized for calcium supplementation.

Where You’ll Find It

E623 appears in a wide range of processed foods where flavor enhancement with calcium provision is desired:

• Soups and broths
• Baked goods (bread, cakes, pastries)
• Sauces and gravies
• Condiments (soy sauce, fish sauce)
• Snack foods
• Processed meats
• Ready-to-eat meals
• Seasonings and spice blends
• Cheese products
• Vegetable-based foods
• Low-sodium products
• Food supplements
• Beverages (less common)
• Bouillon and stock cubes
• Savory spreads

E623 is less commonly used than E621 (sodium MSG) but increasingly selected in health-conscious formulations seeking both flavor enhancement and calcium fortification combined with sodium reduction.

Why Do Food Companies Use It?

E623 performs one critical commercial function with specific advantages over other glutamate salts:

Flavor enhancement with dual nutritional benefits (sodium reduction + calcium): E623 calcium diglutamate enhances natural savory flavors in foods at 0.1-1% concentrations, allowing manufacturers to reduce salt content while simultaneously providing calcium fortification. At 0.1-1%, glutamates amplify umami perception, making foods taste more flavorful without additional salt. The calcium provision offers additional nutritional benefit—distinguishing E623 from E621 (sodium, potentially increasing sodium for cardiovascular-concern consumers) or E622 (potassium, potentially increasing potassium for kidney-concern consumers).

Why calcium salt instead of sodium/potassium: E623 is selected when BOTH sodium reduction AND calcium fortification are desired—allowing marketing of “low-sodium, calcium-fortified” products with enhanced flavor. The dual benefit appeals to health-conscious consumers managing sodium intake and seeking calcium supplementation.

Is It Safe?

E623’s safety status is IDENTICAL to all glutamates (E620-E625)—officially approved but with 2017 EFSA finding that cumulative glutamate exposure EXCEEDS safe levels in vulnerable populations, particularly infants and children, with documented neurotoxic potential.

Regulatory Status—Approved Despite Exposure Concerns (Identical to E621, E622):

• FDA (USA): Generally Recognized As Safe (GRAS); no explicit ADI limit
• EFSA (Europe): Approved; ADI 30 mg/kg bw (expressed as glutamic acid; equivalent to 32 mg/kg expressed as MSG equivalent)
• JECFA (WHO/FAO): Approved; ADI 30 mg glutamic acid/kg bw per day
• CRITICAL ISSUE (2017 EFSA): Cumulative glutamate exposure from food additives, natural sources, and nutrients EXCEEDS ADI in infants, toddlers, children, and adolescents

Documented findings and concerns (IDENTICAL across all glutamates E620-E625):

• No genotoxicity: EFSA concluded no genotoxic concern for all glutamates
• No carcinogenicity: No evidence of carcinogenic potential
• Presystemic metabolism: Glutamate metabolized in gut wall before entering systemic circulation (but metabolism is not complete; some absorption occurs)
• Neurotoxic potential: Glutamate as excitotoxin; underdeveloped blood-brain barrier in children raises vulnerability
• MSG symptom complex: Well-documented at doses >42.9 mg/kg bw: burning sensations, facial pressure, chest pain, headache
• Exposure exceeds safe levels: 2017 EFSA explicitly found typical exposure in children exceeds safe reference doses—IDENTICAL across all glutamate salts
• Vulnerability of infants/children: Blood-brain barrier underdeveloped; cumulative exposure higher relative to body weight; soups and baked goods major sources
• Hidden sources: Glutamate present not only as E623 additive but also naturally (tomatoes, cheese, mushrooms) and as nutrient additions
• Calcium provision: Secondary benefit; does not address glutamate safety concerns

E623 vs Other Glutamates—Functional Comparison

E623 calcium diglutamate shares IDENTICAL safety concerns with all glutamates but offers calcium provision advantage:

• E620 (Glutamic acid): Free acid form; rarely used
• E621 (Monosodium glutamate/MSG): Sodium salt; most commonly used; adds sodium; potential cardiovascular concern for sodium-sensitive consumers
• E622 (Monopotassium glutamate): Potassium salt; reduces sodium; increases potassium; potential concern for kidney-compromised patients
• E623 (Calcium diglutamate): Calcium salt; reduces sodium; provides calcium; IDENTICAL safety concerns as E621, E622; selected for dual benefit (low-sodium + calcium fortification)
• E624 (Monoammonium glutamate): Ammonia salt; rare; IDENTICAL safety concerns
• E625 (Magnesium diglutamate): Magnesium salt; rare; IDENTICAL safety concerns

All share IDENTICAL cumulative exposure and neurotoxic concerns documented in 2017 EFSA.

The 2017 EFSA Re-Evaluation—Applies Identically to E623

The 2017 European Food Safety Authority re-evaluation of all glutamates (E620-E625) reached a critical conclusion applicable to E623: cumulative glutamate exposure from all sources EXCEEDS safe levels in vulnerable populations.

EFSA explicitly found: “Exposure exceeded not only the proposed ADI, but also doses associated with adverse effects in humans” in infants, toddlers, and children at the 95th percentile exposure level. Soups, broths, and fine baked goods for children were identified as primary sources. This assessment applies identically to E623 and all glutamate salts—the salt form (sodium, potassium, or calcium) does not change the fundamental glutamate safety concern.

Production Method

E623 calcium diglutamate is produced through fermentation followed by salt formation:

1. Corynebacterium glutamicum bacteria are cultured in fermentation tanks containing molasses or glucose as substrate
2. Under controlled anaerobic conditions, the bacteria produce glutamic acid as secondary metabolite
3. Glutamic acid is recovered from fermentation broth through precipitation and purification
4. Purified glutamic acid is neutralized with calcium carbonate or calcium hydroxide, forming calcium diglutamate
5. The product is crystallized, dried, and standardized for purity
6. Note: Some production uses genetically modified Corynebacterium glutamicum EA-12 strain (approved in 2015)

Production is fermentation-based with partially natural origin (biological fermentation) combined with chemical salt formation.

Natural vs Synthetic Version

E623 is fermentation-derived with partially natural origin—produced through bacterial fermentation but with chemical salt formation making it technically semi-synthetic.

While glutamic acid is naturally produced by bacteria through fermentation (a natural biological process), E623 is created by isolating the bacterial product and forming a calcium salt—making it technically a synthesized/extracted compound. The distinction is that glutamic acid originates from biological fermentation, but the final product E623 requires synthetic salt formation.

Calcium Provision Advantage

The critical distinction of E623 versus E621 (sodium) and E622 (potassium) is the calcium provision:

E623 provides calcium fortification—useful for calcium-deficient populations and consumers seeking calcium supplementation. This dual benefit (flavor enhancement + calcium provision) appeals to manufacturers targeting health-conscious consumers. However, the calcium benefit does not mitigate the shared glutamate safety concerns—E623 carries IDENTICAL neurotoxic potential and IDENTICAL cumulative exposure concerns as E621 and E622.

Environmental and Sustainability

E623 production through fermentation is relatively sustainable—uses renewable carbohydrate substrates (molasses, glucose), generates minimal waste, and does not rely on petroleum. Fermentation-based production is more sustainable than purely synthetic chemical synthesis. However, agricultural inputs for substrate production carry environmental costs.

Consumer Actions to Minimize E623 and Glutamate Exposure

For consumers concerned about glutamate exposure, particularly protecting children (IDENTICAL to E621, E622 concerns):

• Limit soups and broths (primary source of excessive glutamate)
• Reduce fine baked goods and bakery products for children
• Check labels for “glutamate,” “flavor enhancer,” “E623,” “E621,” “E622”
• Avoid products combining glutamate additives with natural glutamate sources (tomato sauces + E623)
• Prepare home-made foods without added glutamates to reduce cumulative exposure
• Pay special attention to products marketed for children; these commonly exceed safe exposure levels
• Understand that complete avoidance is impractical (glutamate naturally present in many foods) but reducing added forms significantly lowers exposure
• Recognize that “low-sodium, calcium-fortified” labeling addresses sodium/calcium concerns but does NOT address glutamate safety concerns
• Be aware of cumulative exposure across multiple glutamate sources and products

The Bottom Line

E623 (calcium diglutamate) is a fermentation-derived calcium salt of glutamic acid used as a flavor enhancer providing the umami (savory) taste and calcium fortification, officially approved by FDA, EFSA, and JECFA, but sharing IDENTICAL safety concerns as all glutamates (E620-E625) documented in 2017 EFSA re-evaluation: cumulative glutamate exposure from food additives, natural sources, and nutrients EXCEEDS the safe level (ADI of 30 mg/kg bw as glutamic acid) in infants, toddlers, children, and adolescents, with documented neurotoxic potential and MSG symptom complex at high doses, representing the same regulatory paradox as E621 and E622 where approval persists despite scientific evidence of unsafe exposure patterns in vulnerable populations.

E623 is the calcium salt form of glutamic acid, functioning as a flavor enhancer that amplifies perception of umami (savory) taste. It is produced through bacterial fermentation of molasses (natural biological process) followed by chemical salt formation with calcium. At 0.1-1% concentrations, E623 enhances natural food flavors while reducing sodium and providing calcium fortification.

The critical distinction of E623 is that it shares ALL safety concerns documented for glutamates in general—the 2017 EFSA re-evaluation finding that cumulative glutamate exposure EXCEEDS safe levels in vulnerable populations. Unlike E621 (sodium) which increases sodium intake or E622 (potassium) which increases potassium, E623 provides calcium—a secondary benefit that does NOT mitigate the primary safety concern (glutamate neurotoxic potential and cumulative exposure).

The safety concern is not acute toxicity but rather cumulative neurotoxic potential: glutamate is a neurotransmitter, and the underdeveloped blood-brain barrier in children creates vulnerability to excitotoxicity (excessive neuronal stimulation). MSG symptom complex and other adverse effects are documented at high doses (>42.9 mg/kg bw)—doses that are exceeded by typical consumption patterns in vulnerable populations according to 2017 EFSA assessment.

E623 is less commonly used than E621 (MSG) but increasingly selected in health-conscious formulations emphasizing “low-sodium, calcium-fortified” positioning. The calcium fortification appeal should not obscure the fundamental glutamate safety concerns that apply identically to all glutamate salts.

For consumers, E623 represents an identical concern to E621 and E622—a flavor enhancer with cumulative exposure concerns exceeding safe levels in children according to scientific assessment, despite continued regulatory approval.