If you’ve ever flipped a packet over and seen a wall of “E-numbers,” you’re not alone in feeling lost. The codes look alarming, but the truth is more nuanced: an E-number just means an additive has been assessed and approved for use in the EU. Some are harmless — even beneficial. Others are flagged by researchers and regulators for good reason.
This guide cuts through the noise. We’ll explain what additives are, which categories matter, and the specific ones worth keeping an eye on — without the fear-mongering.
What is a food additive, anyway?
A food additive is anything added to a product to do a job: preserve it, colour it, sweeten it, thicken it, or stabilise it. They fall into a few broad groups:
- Colours (E100–E199) — make food look a certain way
- Preservatives (E200–E299) — stop spoilage and bacterial growth
- Antioxidants & acidity regulators (E300–E399) — prevent fats going rancid
- Thickeners, stabilisers & emulsifiers (E400–E499) — control texture
- Sweeteners and others (E900+) — replace sugar, add shine, and more
Most are perfectly safe. The point isn’t to avoid every E-number — it’s to recognise the handful that carry genuine question marks.
How Eatly rates additives
In the Eatly app, every additive a product contains is matched against a safety database and tagged into one of four levels:
- Safe — no penalty (e.g. ascorbic acid, a.k.a. vitamin C)
- Low concern — a small penalty
- Moderate concern — a bigger penalty
- High concern — a large penalty, and the product’s overall score is capped
That’s why two products with similar nutrition can score very differently: additives matter. A product loaded with moderate- and high-concern additives simply can’t reach a top score.
The additives worth a second look
Here are the ones that most often get flagged. “Flagged” doesn’t mean “poison” — it means there’s enough evidence or regulatory concern to be cautious, especially if you’re eating them often.
Artificial colours: the “Southampton Six”
Several azo dyes — E102 (Tartrazine), E104 (Quinoline Yellow), E110 (Sunset Yellow), E122 (Carmoisine), E124 (Ponceau 4R) and E129 (Allura Red) — were linked in a landmark UK study to increased hyperactivity in some children. In the EU, products containing them must carry a warning label. They’re common in sweets, soft drinks and brightly coloured snacks, and they’re easy to avoid once you know the codes.
E171 — Titanium dioxide
A whitening agent that the EU banned as a food additive in 2022 after its food-safety authority could no longer rule out genotoxicity. It may still appear in products from other regions, so it’s worth scanning imports.
Nitrites & nitrates (E249–E252)
Used to cure processed meats like bacon, ham and salami. The concern is well established: the World Health Organization classifies processed meat as a Group 1 carcinogen, and nitrites are part of why. Enjoy these as an occasional treat rather than a daily staple.
E951 — Aspartame
The most-debated sweetener. In 2023 the WHO’s cancer agency classified it as “possibly carcinogenic to humans” (its lowest-evidence category), while food-safety bodies kept the existing acceptable daily intake. The honest takeaway: occasional use is widely considered fine; daily multi-can habits are where it gets murkier.
E320 / E321 — BHA & BHT
Antioxidants that stop fats going rancid. BHA in particular has been flagged in animal studies, and it’s classified as a possible human carcinogen. Found in some chips, gum and processed fats.
E211 — Sodium benzoate
A common preservative that’s generally fine on its own — but it can react with vitamin C (ascorbic acid) to form trace amounts of benzene, a known carcinogen. The combination matters most in soft drinks.
E407 — Carrageenan
A thickener derived from seaweed, common in plant milks and dairy. The research is genuinely mixed: some studies link the degraded form to gut inflammation, while approved food-grade carrageenan is considered acceptable. A “moderate concern” worth watching if you have a sensitive gut.
You don’t need to memorise any of this
That’s the whole point of scanning. Take a jar of Nutella: it’s not the additives that sink its score so much as the sugar and saturated fat — but on plenty of other products, it’s a single high-concern colour or preservative that caps the rating.
Instead of decoding labels in the supermarket aisle, you can:
- Scan the barcode with Eatly
- See every additive named, explained and colour-coded by risk
- Get a better-scoring alternative in the same category
The bottom line
Additives aren’t inherently evil — many are safe, and some (like vitamin C) are actively good. But a small group of colours, preservatives and sweeteners carry real, evidence-based question marks, and they cluster in ultra-processed foods. Knowing the worst offenders — or letting an app flag them for you — is the easiest win for eating cleaner.
Browse scored products to see how your favourites stack up, or scan your own shelf in seconds.