Dimethyl polysiloxane
A silicone-based antifoaming agent added to frying oils and some processed foods to stop foam building up during cooking.
What is it?
Dimethyl polysiloxane is a synthetic silicone polymer made from repeating dimethylsiloxane units. It is a clear, viscous, oily fluid that does not dissolve in water. It is chemically inert and very stable at high temperatures, which is why it is used in industrial and food applications alike.
What does it do?
It lowers the surface tension of hot liquids, breaking up air bubbles before they can form a stable foam. In deep-frying oils, this prevents dangerous foam-over during cooking. In jam and jam-making, it controls foam during boiling. It works physically rather than chemically and is not absorbed in any meaningful quantity by the body, passing through largely unchanged.
Where you will see it
Most commonly found in deep-frying oils sold to caterers and fast-food restaurants, vegetable oils for industrial frying, fruit jams and marmalades (to control foam during manufacture), and some dietary supplements in capsule form (as an excipient). It also appears in some non-alcoholic flavoured drinks and soups at low levels. On a UK food label it appears as dimethyl polysiloxane or E900.
What the science says
Absorption and metabolism
Dimethyl polysiloxane is not significantly absorbed from the gut. Studies in animals show that the vast majority passes through the digestive tract unchanged and is excreted in faeces. Minimal systemic exposure is the basis for the large gap between the ADI and typical dietary intake.
In animal studies, orally administered dimethyl polysiloxane was poorly absorbed from the gastrointestinal tract, with most of the dose recovered intact in faeces.
EFSA's re-evaluation confirmed that absorption from the gut is minimal, noting that the polymer's high molecular weight and lipophilic character mean systemic exposure from food use is very low.
Long-term and toxicological studies
Chronic feeding studies in rodents at high doses showed no carcinogenic or reproductive effects attributable to dimethyl polysiloxane. No genotoxicity was identified in available assays. EFSA's 2020 re-evaluation found no new toxicological data that indicated a concern at permitted use levels.
No carcinogenic, genotoxic or reproductive effects were observed in long-term rodent studies at doses substantially above those expected from food use.
EFSA re-evaluation raised the ADI from 1.5 mg/kg bw/day (SCF 1990) to 17 mg/kg bw/day, based on application of an uncertainty factor of 100 to the most sensitive animal study endpoint.
Estimated dietary exposure vs ADI
EFSA calculated that typical dietary exposure to E900 from all permitted food uses is well below the revised ADI of 17 mg/kg bw/day even in high consumers. The main route of exposure for most people is residues in fried food rather than direct addition, because most of the additive remains in the cooking oil rather than transferring to the food.
Refined dietary exposure estimates for E900 across European populations did not approach the revised ADI of 17 mg/kg bw/day, even in children at the 95th percentile of consumption.
Where it stands with the regulators
Who should be careful
No specific group is advised to avoid E900 on current evidence. People with known silicone sensitivities (rare; usually relevant to medical implants rather than food-grade material) may wish to note it. On a label, look for dimethyl polysiloxane or E900.
The honest read
E900 is one of the more inert food additives in use. It is a large, chemically stable polymer that does not meaningfully enter the body and has been in widespread industrial food use for decades. The main public question tends to be whether it is vegan or whether it is the same substance used in breast implants, to which the honest answers are: it can be animal-derived (see vegan note below) and it is chemically similar to medical-grade silicone but is a different specification and purity grade. EFSA's 2020 re-evaluation reviewed the full toxicological dataset and found no signal that warranted restriction at permitted food use levels. The science here is settled enough that the ADI was raised rather than lowered on re-examination.
Related additives
Common questions
Is E900 banned in the UK?
No. E900 is approved for use in specific food categories in both the UK and EU, including frying oils, jams, soups and food supplements, subject to maximum permitted levels.
Is E900 the same as what is in breast implants?
E900 is a silicone polymer in the same chemical family as medical-grade silicone used in implants, but they are different products. Food-grade dimethyl polysiloxane is a lower-viscosity, lower-molecular-weight material manufactured to food specifications. The two should not be treated as equivalent for safety purposes.
What foods contain E900?
It is most commonly found in commercial frying oils (particularly in fast-food and catering frying), fruit jams and marmalades, and some non-alcoholic flavoured drinks and soups. It also appears in some food supplement capsules as a processing aid.
Is E900 vegan?
Not always. Dimethyl polysiloxane can be manufactured using a catalyst derived from animal fat. Food labelling does not distinguish the production route, so strict vegans may wish to avoid products listing E900 or dimethyl polysiloxane unless the manufacturer confirms a plant-based production route.
Sources
- EFSA Panel on Food Additives and Flavourings: Re-evaluation of dimethyl polysiloxane (E 900) as a food additive
- UK FSA approved additives and E numbers
- EU Regulation 1333/2008 on food additives, Annex II
- JECFA evaluation of dimethyl polysiloxane
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