Thaumatin
A naturally derived sweet protein extracted from a West African fruit, used in tiny amounts to sweeten food and enhance flavour.
What is it?
Thaumatin is a mixture of intensely sweet proteins (primarily thaumatin I and II) extracted from the arils of Thaumatococcus daniellii, a plant native to West Africa. It is approximately 2,000 to 3,000 times sweeter than sucrose by weight, so it is used in very small quantities. Because it is a protein, it provides negligible calories at the concentrations used in food.
What does it do?
Thaumatin binds to sweet taste receptors on the tongue and triggers a sweet sensation. At low concentrations it primarily acts as a flavour modifier and taste enhancer, rounding out or prolonging sweetness from other ingredients. At higher concentrations it functions as a standalone sweetener. It also has a lingering, slightly liquorice-like aftertaste at elevated use levels.
Where you will see it
Most commonly found in chewing gum, confectionery, chocolate products, tabletop sweeteners, food supplements, flavoured drinks, desserts, and some savoury sauces and snack foods. On a UK label it appears as 'thaumatin' or 'E957'.
What the science says
EFSA 2021 re-evaluation: no numerical daily limit needed
The European Food Safety Authority completed a full re-evaluation of thaumatin in 2021. The Panel found no genotoxicity and no adverse effects in animal toxicity studies even at very high doses. It calculated a margin of safety of over 5,000 between the highest estimated human exposure and the lowest dose with no observed effects in animals, and concluded no numerical acceptable daily intake was needed.
No genotoxic potential was identified and no adverse effects were found in animal studies at doses up to 5,200 mg per kilogram of bodyweight per day in rats.
The Panel derived a margin of safety of 5,417 at the 95th percentile human exposure scenario and concluded there was no safety concern at regulatory maximum levels. No numerical ADI was set.
Allergenicity: oral evidence is inconclusive
Because thaumatin is a protein, EFSA examined whether it could trigger allergic reactions when eaten. The Panel reviewed available human data but concluded no firm conclusion on oral allergenicity could be drawn from those data. Occupational inhalation of thaumatin powder has been linked to sensitisation in workers, but this is a different exposure route from eating it in food. No requirement to declare thaumatin as a food allergen currently exists under UK or EU food law.
EFSA concluded that no determination on oral allergenicity could be made from the available human data; inhalation allergenicity in occupational settings was noted but considered not relevant to dietary exposure.
JECFA assessment: no ADI assigned
The Joint FAO/WHO Expert Committee on Food Additives (JECFA) previously evaluated thaumatin and likewise did not assign a numerical acceptable daily intake, reflecting that exposure from food use is far below any level of concern identified in animal studies.
JECFA evaluated thaumatin and set no numerical ADI, considering it acceptable for use as a food additive at the levels required to achieve its sweetening effect.
Where it stands with the regulators
Who should be careful
No specific group is required to avoid thaumatin under current food law. People with known protein allergies who are cautious about novel proteins may wish to note its presence; look for 'thaumatin' or 'E957' on the label. Occupational handlers of thaumatin powder (not consumers) have shown inhalation sensitisation in some studies.
The honest read
Thaumatin is one of the more unusual food additives: it is a protein derived from a real fruit, used in quantities measured in fractions of a milligram, and has been in the food supply for decades. The two formal international assessments (EFSA 2021 and JECFA) both found no numerical daily limit was needed, which reflects how large the gap is between what people actually eat and any dose that produced effects in animal studies. The one genuinely open question is oral allergenicity: EFSA reviewed the human data and could not draw a conclusion either way. That is an honest gap in the evidence, not a cleared concern. Whether it matters in practice for food-consuming populations is unknown.
Related additives
Common questions
Is E957 banned in the UK?
No. Thaumatin is an approved food additive in the UK under the assimilated EU Regulation 1333/2008, as confirmed by the UK Food Standards Agency approved-additives list.
Can thaumatin cause an allergic reaction?
EFSA reviewed the available human data in 2021 and concluded no firm determination on oral allergenicity could be made. Inhalation of thaumatin dust has caused sensitisation in occupational settings, but that is a different exposure route. It is not currently classified as a declarable allergen under UK or EU food law.
What foods contain E957?
Chewing gum, confectionery, chocolate products, flavoured drinks, desserts, sauces, snack foods, food supplements, and tabletop sweeteners. Check the label for 'thaumatin' or 'E957'.
Is E957 vegan?
Yes. Thaumatin is extracted from the fruit of a plant (Thaumatococcus daniellii) and contains no animal-derived ingredients.
Sources
- EFSA Panel on Food Additives and Flavourings: Re-evaluation of thaumatin (E 957) as food additive, EFSA Journal 2021;19(12):e06884
- Re-evaluation of thaumatin (E 957) as food additive - PMC full text
- UK Food Standards Agency: Approved additives and E numbers
- International Sweeteners Association: EFSA re-confirms confidence in Thaumatin
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