Did You Know Azo Dyes Were Reduced After One Study?
The 2007 Southampton study on food colours and children's behaviour led to a UK warning label and prompted many brands to drop azo dyes. What it found, which colours it named, and what it means for sensitive skin.
The fact, stated plainly
In 2007, a study at the University of Southampton suggested that certain artificial food colours, plus the preservative sodium benzoate, were linked to increased hyperactivity in some children. The fallout was significant. The EU and UK brought in a warning label for the colours involved, and many manufacturers quietly reformulated to drop them. This is a matter of established public record, and it is why several colours that were once everywhere are now much harder to find.
The colours involved
The colours the study focused on are often called the “Southampton Six”: tartrazine (E102), quinoline yellow (E104), Sunset Yellow (E110), carmoisine (E122), Ponceau 4R (E124) and Allura Red (E129). Foods containing any of them must carry the line “may have an adverse effect on activity and attention in children”. Most of these are azo dyes, a family of synthetic colours built around a particular chemical structure. You can read more in our overview of tartrazine and other azo dyes.
Why it happened
The study combined a colour mix with sodium benzoate and measured children’s behaviour. It did not prove that any single colour causes a specific effect in a specific child, and the science on behaviour is still debated. What it did do was raise enough concern for regulators to act with a precautionary warning label, and for brands to reformulate rather than carry the warning. So the reduction in azo dyes was as much a commercial and regulatory response as a purely scientific one.
Why it matters for skin
The study was about behaviour, not skin, but it is useful to skin-sensitive shoppers in a practical way. These same colours are among those most often linked to hives and itching in people who react to food additives. And the mandatory warning label gives you a two-second screen in the shop: if you see that warning line, those colours are present. That makes it one of the easiest label cues to use.
Who it affects most
People with chronic hives linked to food additives, and parents managing a child who reacts to brightly coloured foods and drinks. Sweets, fizzy drinks, some ice lollies, cake decorations and cheaper squashes are the classic places these colours turn up.
How to spot and avoid them on a label
- Use the warning line first. “May have an adverse effect on activity and attention in children” means one or more of the Southampton Six is present.
- Then read the ingredients for the specific E numbers: E102, E104, E110, E122, E124, E129, or their names.
- Compare brands. Many products now use alternative colours or none, so a like-for-like swap is often easy.
- Our guide on how to find azo dyes on a label walks through the names to watch for.
What to do about it
If colours flare your skin, note which products set you off and check them against those E numbers. Swapping to uncoloured or naturally coloured versions for a couple of weeks, while keeping a food-and-skin diary, usually makes any pattern clear.
When to see a professional
See your GP if hives are frequent, long-lasting, or hard to link to a cause, and ask a pharmacist about suitable anti-histamines for occasional flares. A dietitian can help run a careful elimination trial. Any reaction with swelling of the lips, tongue or throat, or breathing difficulty, is a medical emergency and needs urgent care.
Check it against your own list
A free database like Open Food Facts and Fig give broad ingredient information rather than a check against your own skin. A personal-list app like ClearaScan lets you save the Southampton colours (and your other triggers) once and scan any product, food, medication or cosmetic, against your ingredient guard list, flagging only yours. Its Reaction Journal lets you tie a flare back to the product, a shared Care Circle lets family scan for you, and a Trusted Products list keeps what you have cleared. It is currently in early access. (Disclosure: our editor co-founded ClearaScan, and we are not paid to mention the others.)
The Sensitive Skin Ingredient Decoder
A free one-page guide to reading a skincare label fast: the irritants to watch, the fragrance loopholes, and what "fragrance-free" and "hypoallergenic" really mean.
Common questions
What did the Southampton study actually find?
The 2007 University of Southampton study suggested that certain artificial food colours, together with the preservative sodium benzoate, were linked to increased hyperactivity in some children. It looked at behaviour, not skin, but it changed how these colours are labelled.
What are the Southampton Six?
They are tartrazine (E102), quinoline yellow (E104), Sunset Yellow (E110), carmoisine (E122), Ponceau 4R (E124) and Allura Red (E129). These are the six colours the study focused on.
What is the warning label about?
Foods sold in the UK and EU that contain any of these six colours must carry the line 'may have an adverse effect on activity and attention in children'. It gives shoppers a quick way to spot those colours are present.
What has this got to do with sensitive skin?
The study was about behaviour, but these same colours are among those most often linked to hives and itching. The mandatory warning label doubles as a fast screen for people whose skin reacts to azo dyes.
Are these colours banned now?
No, they are still legal in the UK and EU with the warning label. Many manufacturers reformulated to remove them anyway, which is why they are now less common than they once were, but they still appear in some products.