Karaya gum
A natural tree gum used to thicken and stabilise foods, particularly ice cream, salad dressings and processed meats.
No concern for genotoxicity, and no toxic effects in animals up to 1,250 mg/kg body weight a day, the highest dose tested.
What is it?
Karaya gum is a dried exudate from the Sterculia urens tree, native to India. It is a complex polysaccharide (partially acetylated galacturono-rhamno-galactan) collected by tapping the bark. The gum swells dramatically in water but does not fully dissolve, forming a viscous gel.
What does it do?
Karaya gum absorbs water and swells to many times its dry volume, creating a thick, cohesive gel at low concentrations. This makes it effective as a thickener, stabiliser and emulsion stabiliser. It resists breakdown under acidic conditions better than many other plant gums, which makes it useful in acid foods such as salad dressings.
Where you will see it
Ice cream and frozen desserts, processed cheese spreads, salad dressings, sauces, meringues, whipped toppings, pharmaceuticals (laxatives and denture adhesives), and some confectionery products. On a UK food label it appears as E416 or karaya gum.
What the science says
Digestibility and metabolic fate
Karaya gum passes through the gut largely intact. It is poorly fermented by intestinal bacteria compared with other plant gums. Because it is not absorbed or broken down into nutritionally significant components, it contributes negligible calories and does not enter the bloodstream.
Karaya gum is practically indigestible and only minimally degraded by intestinal microflora, resulting in negligible systemic absorption.
Genotoxicity and long-term toxicity
Standard genotoxicity tests (mutagenicity, clastogenicity) have returned negative results. Animal feeding studies at high doses did not produce toxic effects in the organs examined. No carcinogenicity signal has been identified.
No genotoxic concern was identified. In animal studies, karaya gum did not induce toxic effects at doses up to 1,250 mg per kilogram of body weight per day.
Allergenicity
Karaya gum is a recognised contact allergen, particularly associated with occupational exposure (nurses and healthcare workers using karaya-based ostomy appliances). Ingested karaya as a food additive appears at much lower levels, but isolated cases of allergic reactions following food consumption have been documented. People with known karaya hypersensitivity should check labels.
Karaya gum is a recognised contact allergen. Occupational exposure (stoma care products) is the primary route of sensitisation; food-intake reactions have been reported in sensitised individuals.
Case reports of allergic reactions to karaya gum in stoma care settings have appeared in the literature since the 1970s, with food-triggered reactions documented in already-sensitised individuals.
Human tolerance at higher intakes
Short-term human studies at doses around 100 mg per kilogram of body weight per day for four weeks reported no adverse effects. Estimated real-world dietary exposure from food use is far below these study doses.
Karaya gum was reported to be tolerated in humans at approximately 100 mg per kilogram of body weight per day over four weeks in short-term studies.
Where it stands with the regulators
Who should be careful
People who know they are allergic to karaya gum should check labels for E416 or karaya gum. Sensitisation most commonly occurs through prolonged skin contact with karaya-based stoma or wound-care products, but once sensitised, food ingestion can trigger a reaction.
The honest read
Karaya gum has a long history of food use and has been reviewed twice by international expert bodies. The 2016 EFSA re-evaluation concluded no numerical ADI was needed given low food-additive exposure and the gum's negligible absorption. The main documented signal is allergenicity in people already sensitised through medical product contact, which affects a small subset of the population. At the levels found in food it does not raise the kinds of concerns associated with synthetic additives or preservatives. The science around it is settled and narrow in scope.
Related additives
Common questions
Is E416 banned in the UK?
No. Karaya gum is approved for food use in the UK under the FSA's approved-additives list and the retained EU Regulation 1333/2008.
Can karaya gum trigger an allergic reaction?
Yes, in people who have been sensitised to it, usually through prolonged skin contact with karaya-based ostomy or wound-care products. Once sensitised, consuming it in food can provoke a reaction. If you have used such products and experienced skin reactions, look for E416 or karaya gum on ingredient labels.
What foods contain E416?
Ice cream, frozen desserts, salad dressings, processed cheese spreads, some sauces and whipped toppings. It can also appear in some confectionery and processed meat products. Look for E416 or karaya gum in the ingredients list.
Is E416 vegan?
Yes. Karaya gum is a plant-derived exudate from the Sterculia urens tree. It contains no animal-derived ingredients and is suitable for vegan diets.
Sources
- EFSA ANS Panel, Re-evaluation of karaya gum (E 416) as a food additive, EFSA Journal 2016;14(2):4598
- UK FSA Approved Additives and E Numbers (Emulsifiers, stabilisers, thickeners and gelling agents)
- JECFA monograph on Karaya gum (Sterculia gum), FAO/WHO
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