Stigmasterol-rich plant sterols
A plant sterol used as an ice-nucleating stabiliser in ready-to-freeze cocktails. Very narrow, specialist use.
EFSA could not establish an acceptable daily intake when it assessed this additive, citing insufficient toxicological data. The permitted use is narrow and the amounts involved are small, but the data gap remains unresolved.
What is it?
Stigmasterol is a phytosterol (plant-derived sterol) found naturally in soya beans, rapeseed, and other vegetable oils. The food additive form is a concentrated extract in which stigmasterol makes up at least 85% of the total phytosterol content (which must itself be at least 95% pure). It is chemically related to cholesterol but comes entirely from plant sources.
What does it do?
In ready-to-freeze alcoholic cocktails, stigmasterol-rich plant sterols act as an ice-nucleating agent. The sterol crystals provide a template that encourages the formation of small, uniform ice crystals when the drink is placed in a home freezer, producing a smooth semi-frozen slush texture rather than a solid block. This function is classified as a stabiliser under food law.
Where you will see it
Used exclusively in ready-to-freeze alcoholic cocktails sold in pouches or bottles intended to be put directly in the freezer. It is not used in standard food products, soft drinks, or dietary supplements under this E number. On a UK label it appears as 'E499' or 'stigmasterol-rich plant sterols'.
What the science says
EFSA could not set a safe daily intake level
When the European Food Safety Authority reviewed this additive in 2012, it concluded that the toxicological data available for stigmasterol-rich plant sterols in this concentrated, purified form were insufficient to establish an acceptable daily intake. This is not the same as finding a harm, but it means the regulator was unable to draw a confident safety boundary from the available evidence. EFSA judged that the amounts consumed from the narrow permitted use (ready-to-freeze cocktails only) were unlikely to raise concern in practice, but the underlying data gap was acknowledged and no ADI was set.
EFSA concluded that toxicological data for stigmasterol-rich plant sterols as a food additive were insufficient to establish an acceptable daily intake, though it considered the proposed use in ready-to-freeze cocktails unlikely to raise safety concerns given the exposure level.
Plant sterols and cholesterol absorption
Plant sterols as a class (including stigmasterol) compete with dietary cholesterol for absorption in the gut, reducing the amount of cholesterol that enters the bloodstream. This is the basis for plant sterol functional foods marketed for heart health. However, the amounts of E499 delivered by ready-to-freeze cocktails at their permitted levels (80 to 800mg/kg) are too small to produce a meaningful cholesterol-lowering effect. At the same time, plant sterols at high intakes can reduce absorption of fat-soluble vitamins and carotenoids, though this has not been studied specifically for E499 at these concentrations.
Plant sterols at doses of 1.5 to 3 g per day reduce LDL cholesterol by approximately 10%, but this level is far above what would be consumed from the narrow food additive use of E499.
Regular consumption of plant sterols at elevated intakes has been associated with modest reductions in plasma carotenoid and fat-soluble vitamin levels in controlled studies.
Sitosterolaemia: a rare genetic condition that requires avoidance
People with sitosterolaemia (also called phytosterolaemia) have a rare inherited metabolic disorder that causes plant sterols to accumulate in the blood and tissues rather than being excreted. In these individuals, dietary plant sterols including stigmasterol can contribute to premature cardiovascular disease, xanthomas (fatty deposits under the skin), and joint problems. The condition is rare but serious, and those affected are advised to restrict all plant sterol intake.
Sitosterolaemia is caused by loss-of-function mutations in the ABCG5 or ABCG8 transporter genes, leading to abnormal accumulation of plant sterols in plasma and tissues and associated cardiovascular risk.
Where it stands with the regulators
Who should be careful
People with sitosterolaemia (phytosterolaemia) should avoid all sources of plant sterols, including products containing E499. Look for 'E499' or 'stigmasterol-rich plant sterols' on the label of ready-to-freeze alcoholic pouches or bottles.
The honest read
E499 is a highly niche additive with a single permitted food use: making cocktail pouches freeze into a slush. The amounts involved are small and the exposure is rare. That said, when EFSA assessed it in 2012, it did not have enough toxicological data on this specific concentrated extract to draw a firm safety boundary, and no ADI was set. That data gap has not been publicly resolved in the years since. For the vast majority of people, encountering this additive at all would be unusual, and the dose from a cocktail pouch is far below the intakes associated with any known effects of plant sterols. For the small number of people with sitosterolaemia, any plant sterol source is a concern regardless of dose.
Related additives
Common questions
Is E499 banned in the UK?
No. E499 is approved for use in the UK, authorised under assimilated EU law as of 31 December 2020. It is permitted specifically in water-based and cream-based ready-to-freeze alcoholic cocktails at defined maximum levels.
Why did EFSA not set an acceptable daily intake for E499?
When EFSA reviewed E499 in 2012, the toxicological data submitted for this specific concentrated extract of stigmasterol-rich plant sterols were not sufficient to establish a numerical ADI. EFSA considered that the actual exposure from the narrow permitted use was unlikely to raise concern in practice, but it did not have the data to draw a firm safety boundary. No ADI was set as a result.
What foods contain E499?
E499 is approved only in ready-to-freeze alcoholic cocktails, the kind sold in a pouch or bottle that you put in a home freezer to produce a slush drink. It is not used in standard foods, non-alcoholic drinks, or dietary supplements under this E number.
Is E499 vegan?
Yes. Stigmasterol-rich plant sterols are extracted from plant sources such as soya beans and rapeseed oil. No animal-derived ingredients are involved in the production of E499.
Sources
- UK FSA regulated products database: E499 Stigmasterol-rich plant sterols
- Commission Regulation (EU) No 739/2013 amending Annex II to Regulation (EC) No 1333/2008 (adding E499)
- EFSA ANS Panel opinion on stigmasterol-rich plant sterols as a food additive, EFSA Journal
- Commission Regulation (EU) No 231/2012 laying down specifications for food additives (includes E499 specs)
- Berge KE et al. Accumulation of dietary cholesterol in sitosterolemia caused by mutations in adjacent ABC transporters, Science 2000
- EFSA NDA Panel opinion on plant sterols and LDL-cholesterol reduction, EFSA Journal
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