E251 (Sodium nitrate) is a chemical compound, the inorganic nitrate salt of sodium. 

It appears in the form of a white powder.

What it is used for and where

Food

Ingredient listed in European food additives as E251, preservative. The inclusion of nitrites and nitrates in food for preservation purposes is associated with an increased risk of cancer. However, there are studies that consider a comprehensive re-evaluation of the health effects of food sources of nitrates and nitrites to be appropriate. (1).

Cosmetics

Oral care agent. This ingredient can be placed in the oral cavity to improve and/or maintain oral hygiene and health, to prevent or improve a disorder of the teeth, gums, mucous membrane.

Soothing. Ingredient with the task of restoring moisture to the skin, helping in the healing process of irritation, inflammation and skin disorders.

Safety

The food safety experts who checked this ingredient believe that, in addition to a dose of 3.7 mg/kg body weight per day as the acceptable daily intake (ADI), it must be considered that, if all sources of exposure to food nitrates (food additive, natural occurrence and contamination) are taken into account, the ADI would be exceeded for all age groups at the average and highest exposure (2).

The most relevant studies on this ingredient have been selected with a summary of their contents:

Sodium nitrate studies

• Molecular Formula     NaNO₃     NNaO₃
• Molecular Weight    84.995  
• CAS  7631-99-4
• UNII    8M4L3H2ZVZ
• EC Number   231-554-3
• DSSTox ID  DTXSID6020937
• IUPAC  sodium;nitrate
• InChl=1S/NO3.Na/c2-1(3)4;/q-1;+1
• InChl Key      VWDWKYIASSYTQR-UHFFFAOYSA-N
• SMILES  [N+](=O)([O-])[O-].[Na+]
• MDL number  MFCD00011119
• PubChem Substance ID    329824455
• ChEBI  63005
• RTECS  WC5600000
• NCI    C84161
• ICSC    0185
• NACRES  NA.55    
• UN    1498

Synonyms:

• potassium butylxanthate
• butylpotassiumxanthogentate

References_____________________________________________________________________

(1) Hord NG, Tang Y, Bryan NS. Food sources of nitrates and nitrites: the physiologic context for potential health benefits. Am J Clin Nutr. 2009 Jul;90(1):1-10. doi: 10.3945/ajcn.2008.27131.

(2) EFSA Panel on Food Additives and Nutrient Sources added to Food (ANS); Mortensen A, Aguilar F, Crebelli R, Di Domenico A, Dusemund B, Frutos MJ, Galtier P, Gott D, Gundert-Remy U, Lambré C, Leblanc JC, Lindtner O, Moldeus P, Mosesso P, Oskarsson A, Parent-Massin D, Stankovic I, Waalkens-Berendsen I, Woutersen RA, Wright M, van den Brandt P, Fortes C, Merino L, Toldrà F, Arcella D, Christodoulidou A, Barrucci F, Garcia A, Pizzo F, Battacchi D, Younes M. Re-evaluation of sodium nitrate (E 251) and potassium nitrate (E 252) as food additives. EFSA J. 2017 Jun 15;15(6):e04787. doi: 10.2903/j.efsa.2017.4787.