Xanthan gum
A natural thickener made by fermenting sugar with bacteria. Used to give sauces, dressings and gluten-free foods their texture.
What is it?
Xanthan gum is a high-molecular-weight polysaccharide (a long-chain sugar molecule) produced by fermenting glucose or sucrose with the bacterium Xanthomonas campestris. The resulting gum is dried and milled into a cream-coloured powder. It is not chemically synthesised.
What does it do?
When dissolved in water, xanthan gum forms a viscous gel. Even at very low concentrations (0.1 to 0.5%) it dramatically increases a liquid's thickness and prevents ingredients from separating. It is shear-thinning, meaning it thins when stirred or pumped and re-thickens at rest, which makes it practical for both manufacturing and pouring at home.
Where you will see it
Salad dressings, tomato ketchup, mayonnaise, pasta sauces, gravies, soups, ice cream, sour cream, fruit juices, gluten-free breads and pastries (where it replaces the structure gluten provides), low-fat dairy products, and some beverages. On a UK label it appears as 'xanthan gum' or 'E415'.
What the science says
Digestive effects at high doses
Because xanthan gum is not absorbed in the small intestine, it passes to the large intestine where gut bacteria can ferment it. In a clinical study, adults consuming doses far above typical dietary exposure reported some abdominal bloating and loose stools. At the amounts normally eaten through food, most people experience no noticeable effect.
Adults consuming up to 214 mg/kg body weight per day for ten days (roughly 50 times normal dietary exposure) experienced abdominal discomfort in some cases; the panel classified this as an undesirable but non-adverse effect.
Use in specialist infant formula
Xanthan gum is used as a thickener in specialist formula for infants with certain medical conditions. Case reports from the early 2010s, largely involving a specific thickened feed product (SimplyThick), raised concerns about necrotising enterocolitis in premature and very young infants. EFSA subsequently reviewed the evidence specifically for authorised food-additive uses and, in 2023, concluded that use in specially formulated medical foods for infants does not raise safety concerns at permitted concentrations. The necrotising enterocolitis signal was associated with a different product and context, not with E415 as a general food additive.
Case reports in the early 2010s linked a xanthan-gum-based thickened feed product (SimplyThick) to necrotising enterocolitis in premature and very young infants; the US FDA issued a safety alert in 2011.
EFSA reviewed xanthan gum use in food for special medical purposes for infants below 16 weeks and concluded no adverse events of clinical significance were observed; the margin of exposure was considered sufficient given the substance's lack of systemic absorption.
Allergen considerations: corn and soy fermentation substrate
Xanthan gum is most commonly fermented on corn (maize) or soy-based media. Whether residual proteins from those substrates survive into the final product in amounts that could trigger reactions in people with severe corn or soy allergies is debated. The gum itself is not a declarable allergen under UK food law, and regulatory reviews have not required an allergen label. People with very severe corn or soy allergies sometimes choose to avoid it as a precaution.
Xanthan gum is not classified as a declarable allergen under UK food allergen labelling law (the 14 major allergens listed under assimilated Regulation EU 1169/2011 do not include xanthan gum or its fermentation substrates).
Regulatory re-evaluation outcome
EFSA completed a systematic re-evaluation of xanthan gum as part of its programme to reassess all pre-2009 approved additives. The panel found no numerical acceptable daily intake was needed, meaning it did not identify a dose level of concern at realistic human exposures from food.
The EFSA ANS Panel concluded that no numerical ADI was necessary for xanthan gum and identified no safety concern for the general population based on a refined dietary exposure assessment.
Where it stands with the regulators
Who should be careful
People with very severe corn or soy allergies sometimes choose to avoid it, as the fermentation substrate can be corn- or soy-based, though residual protein levels in the finished additive are extremely low and it is not a declarable allergen under UK law. People with irritable bowel syndrome who are sensitive to fermentable fibres may notice digestive discomfort with very high intakes. Look for 'xanthan gum' or 'E415' on the label.
The honest read
Xanthan gum has been used in food manufacturing since the 1960s and has been reviewed multiple times by EFSA and the US FDA. The science is unusually consistent for a food additive: no carcinogen classification, no endocrine signal, no ban or restriction in any major jurisdiction. The most debated area is its use in infant feeds for medically vulnerable babies, where a 2011 US safety alert about a specific thickening product prompted a re-examination of the evidence; EFSA's 2023 review found no safety concern for authorised food-additive uses. The everyday-food picture is not a live scientific controversy.
Related additives
Common questions
Is E415 banned in the UK?
No. Xanthan gum (E415) is approved for use across a wide range of food categories in the UK under assimilated EU Regulation 1333/2008 and the UK FSA approved-additives list.
Is xanthan gum linked to digestive problems?
At the very high doses used in clinical studies (far above what you would eat through food), some people reported bloating and loose stools. At amounts typically found in food, most people notice nothing. People who are sensitive to fermentable fibres, such as those with IBS, may be more reactive at higher intakes.
What foods contain E415?
Salad dressings, mayonnaise, ketchup, pasta sauces, ice cream, soups, fruit juices, and gluten-free bread and pastries are the most common sources. It appears on the label as 'xanthan gum' or 'E415'.
Is E415 vegan?
Yes. Xanthan gum is produced by bacterial fermentation of plant sugars and contains no animal-derived ingredients. It is widely used in vegan and vegetarian products.
Sources
- EFSA ANS Panel, Re-evaluation of xanthan gum (E 415) as a food additive, EFSA Journal 15(6):4909
- EFSA ANS Panel, Re-evaluation of xanthan gum (E 415) as a food additive in foods for infants below 16 weeks of age, EFSA Journal 2023
- UK FSA Approved Additives and E Numbers
- US FDA Safety Alert: SimplyThick thickening agent and necrotising enterocolitis in premature infants
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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