Sodium carbonates
Mineral salts used to make baked goods rise, balance acidity, and stop powders from clumping.
What is it?
E500 covers three related mineral salts: sodium carbonate (washing soda), sodium hydrogen carbonate (bicarbonate of soda, baking soda), and sodium sesquicarbonate (a hydrated mix of the two). All are naturally occurring compounds of sodium, carbon, and oxygen. Sodium bicarbonate is the form most commonly used in food.
What does it do?
In baking, sodium bicarbonate reacts with acids in a dough or batter (such as buttermilk, yoghurt, lemon juice, or acidic raising agents) to release carbon dioxide gas, which causes the mixture to expand and lighten. Sodium carbonate is more strongly alkaline and is used to raise the pH of foods such as cocoa powder (Dutch-processing) or noodles, altering texture and flavour. As an acidity regulator, the salts buffer a product to a target pH. As an anti-caking agent in dry mixes and powders, they absorb moisture and keep particles free-flowing.
Where you will see it
Most commonly found in biscuits, cakes, scones, bread, crackers, and other baked goods as a leavening agent. Also used in cocoa powder processing, Asian-style noodles (giving them a chewy yellow texture), fizzy bath products, effervescent tablets, certain cheeses, and dry powder mixes. On a UK ingredient label it appears as sodium bicarbonate, sodium carbonate, bicarbonate of soda, baking soda, or simply E500.
What the science says
Sodium and blood pressure
E500 salts contribute sodium to the diet, and high sodium intake is a well-established risk factor for raised blood pressure and cardiovascular disease. In practice, the sodium contributed by E500 in baked goods is a small fraction of overall dietary sodium, most of which comes from table salt. People on a medically advised low-sodium diet should be aware that processed baked goods and convenience foods can carry meaningful sodium from multiple sources including E500.
High dietary sodium intake is causally linked to elevated blood pressure and increased cardiovascular risk. The UK Scientific Advisory Committee on Nutrition (SACN) recommends adults limit sodium to no more than 2400mg per day (6g salt).
Regulatory safety assessment
The European Food Safety Authority (EFSA) has evaluated sodium carbonates as food additives. The panel concluded that at the levels used in food there is no toxicological concern, and no numerical Acceptable Daily Intake was considered necessary. The salts are also approved in the UK following assimilation of EU food additive legislation.
EFSA's Panel on Food Additives and Nutrient Sources added to Food (ANS) reviewed sodium carbonates and found no evidence of genotoxicity or other toxicological concern at intended use levels in food, concluding a numerical ADI was not needed.
Where it stands with the regulators
Who should be careful
People on a medically supervised very low-sodium diet should account for sodium from all sources, including baked goods that use E500 as a raising agent. Look for sodium bicarbonate, sodium carbonate, or E500 in the ingredients list.
The honest read
Sodium bicarbonate has been used in kitchens for over 150 years. It is a simple mineral salt that works by a straightforward chemistry: acid plus alkali produces carbon dioxide. The science on these salts is well-established and uncontroversial. The only practical consideration for most people is that it adds a small amount of sodium to the diet, which matters if someone is tracking total sodium intake for medical reasons. There are no open questions about novel toxicology, no contested study findings, and no regulatory bodies have flagged concern at food-use levels.
Related additives
Common questions
Is E500 banned in the UK?
No. Sodium carbonates (E500) are on the UK FSA approved-additives list and permitted in a wide range of foods under UK food law, which retained the relevant EU regulations after Brexit.
Does E500 contain allergens?
Sodium carbonates are not declarable allergens under UK food law. They do not contain gluten, milk, eggs, nuts, or any of the 14 major allergens. However, the finished product they appear in may contain allergens from other ingredients.
What foods contain E500?
Biscuits, cakes, scones, soda bread, crackers, and most commercially baked goods. Also Dutch-processed cocoa powder, certain East Asian noodles, effervescent tablets, and dry powder mixes. Check the ingredients list for sodium bicarbonate, sodium carbonate, bicarbonate of soda, baking soda, or E500.
Is E500 vegan?
Yes. Sodium carbonates are inorganic mineral salts with no animal-derived components. E500 itself is suitable for vegans, though the foods it appears in may contain other non-vegan ingredients.
Sources
Aaron Keen is the founder of NutraSafe. He researches and writes every additive entry himself, from the primary sources. About the research →
This is a guide, not medical advice. If an additive affects you, speak to your GP or a dietitian.
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