Ascorbyl palmitate
A fat-soluble form of vitamin C added to oily and fatty foods to slow down oxidation and extend shelf life.
EFSA could not set a safe daily intake level due to limited toxicological data. In infant formula, ascorbyl palmitate can push vitamin C intake well above recommended levels for the youngest infants.
What is it?
Ascorbyl palmitate is made by chemically bonding ascorbic acid (vitamin C) to palmitic acid (a common saturated fatty acid). Unlike plain vitamin C, which dissolves in water, ascorbyl palmitate dissolves in fat, making it useful as an antioxidant in oily foods. It breaks down in the gut into its two component parts before being absorbed.
What does it do?
It donates electrons to free radicals in fat-containing foods, breaking the chain reaction that turns oils rancid. Because it works within the fatty portion of a food matrix, it protects flavour, colour and nutritional content far more effectively than water-soluble vitamin C in these applications.
Where you will see it
Most commonly used in vegetable oils, margarines, spreads, cooking fats, baby formula, biscuits, crisps and other fatty snack foods. Also found in fat-based vitamin supplements and some fried convenience foods. On a UK label it appears as 'ascorbyl palmitate' or 'E304'.
What the science says
EFSA could not set a daily intake limit
When EFSA re-evaluated E304 in 2015, the panel found the available toxicology studies too limited to calculate a reliable acceptable daily intake. This is unusual and means the usual safety margin calculation was not possible. The panel's conclusion of no safety concern at current use levels rested mainly on the assumption that ascorbyl palmitate breaks down fully into ascorbic acid and palmitic acid before entering the bloodstream, supported by one in vitro study and limited human data.
EFSA concluded that the available toxicological data were too limited to establish an ADI for ascorbyl palmitate; no numerical acceptable daily intake was set.
The safety conclusion relied on the assumption of near-complete pre-systemic hydrolysis to ascorbic acid and palmitic acid, supported by one in vitro study and limited human pharmacokinetic data.
Infants below 16 weeks: vitamin C overshoot
A 2020 EFSA follow-up opinion specifically addressed infants under 16 weeks, a group excluded from the 2015 review. At the maximum permitted levels in infant formula and foods for special medical purposes, the ascorbic acid released from ascorbyl palmitate could push total vitamin C intake to around 266% of the adequate intake for very young infants. EFSA concluded this did not raise health concerns, but noted the evidence base was weak: only six clinical studies were available, five of which were rated as high risk of bias.
At maximum permitted levels, ascorbic acid intake from ascorbyl palmitate in infant formula could reach approximately 266% of the adequate intake for infants below 16 weeks.
Of six studies reviewed for the infant population, five were rated as high risk of bias and none included a proper control group unexposed to ascorbyl palmitate, limiting the strength of the evidence base.
Specification impurities flagged
EFSA recommended tightening the purity specifications for commercially manufactured ascorbyl palmitate to limit potential residual heavy metals (lead, arsenic, mercury) and residual solvents used in its manufacture (acetone, petroleum ether). This is a manufacturing quality concern rather than a dietary hazard from the additive itself.
EFSA recommended that specifications for ascorbyl palmitate should include limits for lead, arsenic, mercury and residual solvents including acetone, petroleum ether and mesityl oxide.
Where it stands with the regulators
Who should be careful
Parents of very young infants (below 4 months) fed formula may wish to check whether formula contains E304, particularly if the infant is already receiving vitamin C from other sources, as permitted levels can push total vitamin C intake well above recommendations. Look for 'ascorbyl palmitate' or 'E304' on the ingredients list.
The honest read
For most adults and older children, ascorbyl palmitate is a mundane fat-soluble antioxidant derived from two ordinary nutritional components, vitamin C and palmitic acid. The catch is that EFSA's 2015 review found the underlying toxicology database thin enough that a standard acceptable daily intake could not be calculated, which is not the norm for long-established food additives. For the general adult population eating it at typical dietary levels this data gap has no practical consequence. The picture is slightly less clear for the youngest infants in formula, where permitted amounts can deliver substantially more vitamin C than guidance recommends, and where the clinical evidence examined was rated as weak. The science here is not alarming but it is not fully settled either.
Related additives
Common questions
Is E304 banned in the UK?
No. Ascorbyl palmitate (E304) is approved for use in the UK under the UK FSA approved-additives list and assimilated EU Regulation 1333/2008.
Why could EFSA not set a safe daily intake level for E304?
When EFSA re-evaluated E304 in 2015, it found the available animal and human toxicology studies too limited to calculate a reliable acceptable daily intake. The regulator concluded that current dietary exposure does not raise health concerns based on what is known, but the data gaps mean the usual numerical safety margin could not be calculated.
What foods contain E304?
Ascorbyl palmitate is most commonly found in vegetable oils, margarines, fat spreads, infant formula, biscuits, crisps, fried snack foods and fat-soluble vitamin supplements. Look for 'ascorbyl palmitate' or 'E304' on the ingredients list.
Is E304 vegan?
Generally yes. Ascorbyl palmitate is synthesised from ascorbic acid (vitamin C, which is typically fermented from plant sugars) and palmitic acid (most commonly derived from palm oil or coconut oil). Animal-derived palmitic acid sources exist but are not standard in food-grade manufacturing. If strict vegan status matters, check with the specific manufacturer.
Sources
- EFSA Scientific Opinion on the re-evaluation of ascorbyl palmitate (E 304(i)) and ascorbyl stearate (E 304(ii)) as food additives, EFSA Journal 2015;13(11):4289
- EFSA Opinion on the re-evaluation of ascorbyl palmitate (E 304i) as a food additive in foods for infants below 16 weeks of age (2020), PMC7448004
- UK Food Standards Agency: Approved additives and E numbers
- EU Regulation 1333/2008 on food additives (Annex II)
See this on every food you scan
NutraSafe reads the label and puts every additive into plain English, with the source, right in the app.
Get NutraSafe on the App Store