Guar gum
A natural thickener ground from guar bean seeds, used to give foods a smooth, gel-like texture without altering their taste.
High-dose guar gum slimming tablets were withdrawn after swelling on contact with fluid caused throat and gut blockages; this concerns concentrated supplement doses, not the small amounts used to thicken food.
What is it?
Guar gum is a polysaccharide (a long-chain carbohydrate) obtained by milling the endosperm of the guar plant (Cyamopsis tetragonoloba), a legume grown mainly in India and Pakistan. It consists largely of galactomannan, a fibre-like molecule that swells and becomes very viscous when it absorbs water. It is off-white, odourless, and tasteless.
What does it do?
When dispersed in water it forms a thick, stable gel at low concentrations. This viscosity prevents ingredients from separating, keeps textures smooth, and slows the rate at which starchy foods become hard after baking. Because it is not digested in the small intestine it also behaves as a soluble dietary fibre, slowing glucose absorption and adding bulk.
Where you will see it
Ice cream, yogurt, cream cheese, salad dressings, soups, sauces, gluten-free breads and pasta, diet foods, infant formula thickeners, and processed meat products. It appears on labels as "guar gum" or "E412".
What the science says
Digestive tolerance at high intakes
Guar gum is not absorbed in the gut and passes into the large intestine where gut bacteria ferment it. At the doses found in food this fermentation is mild and well-established as a normal fibre response. Very high supplemental doses (several grams as a tablet diet aid) caused oesophageal and small bowel obstruction in isolated case reports in the 1990s; such tablet supplements were subsequently withdrawn. Amounts used as a food additive are far lower.
High-dose guar gum tablet supplements caused oesophageal and intestinal obstruction in multiple case reports in the late 1980s and early 1990s, leading to their withdrawal from sale as slimming aids in several countries.
At doses used as a food additive (typically well under 1g per portion), guar gum is fermented in the colon similarly to other soluble dietary fibres without clinically significant adverse effects in healthy adults.
Use in infant foods
EFSA carried out a specific re-evaluation in 2024 on whether guar gum is appropriate as a thickener in formula for infants below 16 weeks. The panel examined data on whether the viscosity guar gum creates in formula could slow gastric emptying or reduce nutrient absorption in very young infants. This is a distinct question from adult use and the review was triggered by a request to extend its permitted uses in infant products.
EFSA's 2024 opinion re-evaluated guar gum for use in foods for infants below 16 weeks and as a follow-up to its 2017 general population review, examining whether current permitted uses raise a safety concern for any population group including infants.
Ethylene oxide contamination in supply chain
In 2020 to 2021 a wave of RASFF alerts across Europe identified ethylene oxide contamination in several food additives including guar gum, introduced during agricultural post-harvest treatment of the seeds. Ethylene oxide is a genotoxic carcinogen. The contamination was not a property of guar gum itself but of the farming and handling practices of specific batches. Regulators set interim limits and required testing of incoming consignments. The UK FSA proposed a 0.1mg/kg limit for ethylene oxide in affected additives.
Ethylene oxide, a genotoxic carcinogen, was detected in multiple guar gum batches distributed across EU member states between 2020 and 2021, triggering a series of product recalls and RASFF notifications.
The UK Food Standards Agency proposed setting a maximum level of 0.1mg/kg for ethylene oxide in food additives including guar gum as part of a consultation on additive contaminant limits.
Legume allergy cross-reactivity
Guar gum is derived from a legume. A small number of case reports have documented allergic reactions, including occupational asthma, in people exposed to guar gum dust in food manufacturing settings. Cross-reactivity with other legumes such as peanuts, soy, and lentils is theoretically possible, though the clinical evidence for cross-reactivity via food consumption (rather than dust inhalation) is limited. Guar gum is not a declarable allergen under UK food law.
Occupational asthma and rhinitis have been reported in food-industry workers exposed to guar gum dust, consistent with its legume origin.
Guar gum is not listed among the 14 major declarable allergens under UK food labelling regulations (UK Food Information Regulations 2014 / assimilated EU FIR 1169/2011), so it does not require a bold allergen declaration.
Where it stands with the regulators
Who should be careful
People with known legume allergies (particularly to guar, locust bean, or related pulses) should check ingredient lists for "guar gum" or "E412" and discuss cross-reactivity risk with a healthcare professional. No other specific group is required to avoid it under current UK food law.
The honest read
Guar gum has been used in food for decades and its basic function as a thickener is well understood. The main regulatory discussions in recent years have not been about the gum itself but about contamination introduced during farming and post-harvest treatment of the seeds (ethylene oxide), which is a supply-chain quality issue rather than an inherent property of the additive. The question of its appropriateness in infant formula is an ongoing area of regulatory attention, with EFSA examining the evidence specifically for very young infants. For adults and older children, the science is long-established.
Related additives
Common questions
Is E412 banned in the UK?
No. Guar gum (E412) is an approved food additive in the UK under the UK FSA's approved-additives list and assimilated EU Regulation 1333/2008. It is permitted in a wide range of food categories.
What was the ethylene oxide contamination issue with guar gum?
Between 2020 and 2021, testing across Europe found ethylene oxide, a genotoxic carcinogen, in certain batches of guar gum imported from specific suppliers. The contamination came from agricultural use of ethylene oxide as a post-harvest fumigant on the seeds, not from the additive itself. Affected batches were recalled. The UK FSA subsequently proposed setting a maximum contaminant limit of 0.1mg/kg for ethylene oxide in food additives. Guar gum's approved status was not revoked.
What foods contain E412?
You will commonly find it in ice cream, yogurt, cream cheese, salad dressings, soups, gluten-free breads and pasta, processed meats, infant formula, and diet products. The label will say "guar gum" or "E412".
Is E412 vegan?
Yes. Guar gum is derived entirely from the guar plant (a legume) with no animal-derived ingredients or processing steps, so it is vegan and vegetarian.
Sources
- UK FSA: Approved additives and E numbers - E412
- UK Food Standards Agency: Approved additives and E numbers
- EFSA ANS Panel: Re-evaluation of guar gum (E 412) as a food additive, EFSA Journal 2017
- EFSA FAF Panel: Re-evaluation of guar gum (E 412) for infant foods and follow-up, EFSA Journal 2024:8748
- European Commission RASFF Portal: ethylene oxide in food additives
- Malo JL et al., Occupational asthma caused by guar gum, Journal of Allergy and Clinical Immunology
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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