Artificial Food Dyes: What They Are and How to Avoid Them
- , by SANUSq Research team
- 9 min reading time
The eye-popping colours of many sweets, cereals, drinks and snacks rarely come from anything natural. They come from synthetic dyes — and whether they belong in our food, especially our children's food, is a genuine and unresolved debate. This is a plain account of what artificial food dyes are, what the research on food dyes side effects does and doesn't show, and how to cut back if you'd rather not have them.
What are artificial food dyes?
Artificial (synthetic) food dyes are chemical colourings, most originally derived from petroleum, added to food purely for appearance. The common ones you'll spot on ingredient lists include tartrazine (E102, Yellow 5), sunset yellow (E110, Yellow 6), allura red (E129, Red 40), ponceau 4R (E124), carmoisine (E122) and quinoline yellow (E104). They do nothing for nutrition, taste or safety — their sole job is to make products look brighter, more appealing and more consistent, and to make cheap ingredients look premium.
They're used in tiny quantities, but they add up: a child working through brightly coloured cereals, squashes, sweets and iced treats across a day can take in a surprising cumulative dose — exactly the scenario the behavioural research examined.
Why they're everywhere
Colour powerfully shapes how we perceive food: we expect strawberry things to be red and citrus things to be yellow, and manufacturers know a vivid colour sells, particularly to children. Synthetic food dyes are cheap, intensely coloured and stable, which is why they've become ubiquitous in ultra-processed foods — the same foods that tend to be high in sugar, salt and refined ingredients. So dyes are often a marker of a broader nutritional problem, not just a colouring question. That association is worth holding onto: cutting synthetic dyes and cutting ultra-processed food are largely the same project.
Where the dyes hide
The obvious places are sweets, fizzy and squash drinks, brightly iced cakes and children's cereals. But synthetic colours also appear in less obvious products: flavoured yoghurts, sauces and condiments, pickles, some medicines and supplements, and foods marketed as 'fruit' flavoured that contain little or no actual fruit — the colour doing the job the fruit isn't.
The hyperactivity question
The biggest concern around food dyes is their possible effect on children's behaviour — and here there's real, if debated, evidence.
A landmark randomised, double-blind, placebo-controlled trial (the "Southampton study") found that mixes of artificial food colours and the preservative sodium benzoate increased hyperactive behaviour in both 3-year-old and 8/9-year-old children from the general population — not just those already diagnosed with hyperactivity (McCann et al., 2007).
The mechanism isn't fully understood — it may involve effects on neurotransmitters or histamine release in susceptible children rather than a single toxic pathway — which is part of why the debate has run so long.
It's important to be balanced about what this does and doesn't show. The effect sizes were modest, not every child reacted, and the mixtures combined dyes with a preservative, so the science isn't a slam-dunk. But the study was large and rigorous enough to prompt action: in the European Union, foods containing these colours must now carry a warning that they "may have an adverse effect on activity and attention in children", and many manufacturers reformulated with natural colours as a result. In the United States the FDA reviewed the same evidence and concluded it didn't warrant a ban — a striking transatlantic difference of opinion over the same data.
Other concerns
Behaviour isn't the only issue raised about synthetic dyes, so it is worth asking what the wider research on food coloring dangers actually establishes — and how firmly.
A toxicological review of food dyes concluded that some raise safety questions — ranging from allergic-type reactions to concerns flagged in animal studies — and argued that the evidence justified more caution and better safety testing than dyes have historically received (Kobylewski & Jacobson, 2012).
Some individuals also report allergic-type or intolerance reactions to specific dyes (tartrazine is a classic example); what people describe as a food dye allergy may be a reaction of this kind rather than a classic, immune-mediated food allergy. Regulators continue to reassess them: some dyes have been restricted or banned in various countries over the years, and the direction of travel — particularly in Europe — has been toward tighter labelling and a shift to plant-based colours.
Recent developments — fresh scrutiny of specific dyes and some high-profile restrictions — suggest the regulatory tide is slowly turning toward caution, even where outright bans remain contested.
How to cut back on artificial dyes
Whatever your read of the evidence, reducing synthetic dyes is a reasonable, low-cost choice — and it tends to improve diet quality anyway, because dyes cluster in ultra-processed foods. Practical steps:
- Read ingredient lists. Look for the E-numbers and colour names above; if a food is an unnatural colour, check why.
- Favour whole, minimally processed foods, which rarely need added colour.
- Choose products coloured naturally — with beetroot, turmeric, paprika, spirulina or fruit-and-vegetable extracts.
- Be extra mindful with children's foods, where dyes are most concentrated and the behavioural concern is greatest.
None of this needs to become an anxious label-reading crusade. The single most effective move is the simplest: the more of your diet that comes from whole, home-prepared food, the fewer synthetic dyes you'll meet without even trying — they live almost entirely in ultra-processed products.
Frequently asked questions
Are food dyes worse for children than adults?
The concern is greatest for children, for two reasons: the behavioural research focused on them, and children eat more of the brightly coloured products where dyes concentrate while weighing far less, so their relative dose is higher. Cutting dyes from children's diets is the sensible priority.
Do food dyes really cause hyperactivity?
The evidence suggests some children's behaviour can be affected: the rigorous Southampton study found artificial colours (with a preservative) increased hyperactivity in general-population children. The effects were modest and not universal, and the science is debated — but it was enough for the EU to require warning labels. It's a reasonable-caution issue, especially for children.
What should I know about red 40 side effects and the other dyes people ask about?
Allura red (E129, Red 40) is one of the colours people ask about most, and the questions about red 40 side effects rest on the same behavioural and toxicological evidence set out above — suggestive, debated and far from settled, rather than proof of harm from any single dye. The most-discussed are tartrazine (E102), sunset yellow (E110), allura red (E129), ponceau 4R (E124), carmoisine (E122) and quinoline yellow (E104). In the EU, foods with several of these must carry a warning about effects on children's activity and attention.
Are artificial food dyes banned anywhere?
Regulation varies by country and changes over time; some dyes have been restricted or banned in certain places, and the EU requires warning labels on several. The US has historically been more permissive, though this too is under ongoing review — a real transatlantic difference over the same evidence.
How can I avoid them?
Read labels for the colour names and E-numbers, favour whole and minimally processed foods, and choose products coloured with natural sources like beetroot, turmeric or paprika. Since dyes concentrate in ultra-processed foods, cutting them usually improves your diet overall.
Are natural food colours safer?
Natural colourings (from beetroot, turmeric, paprika, spirulina and the like) avoid the specific concerns raised about synthetic dyes and are generally regarded as lower-risk, which is why many manufacturers switched to them after the Southampton findings. As always, the bigger win is simply eating fewer heavily processed, brightly coloured foods.
In short: you needn't fear a birthday cake, but making dyed ultra-processed foods the exception rather than the daily norm is a sound, low-effort call — especially for children.
References
- McCann D, Barrett A, Cooper A, et al. Food additives and hyperactive behaviour in 3-year-old and 8/9-year-old children in the community: a randomised, double-blinded, placebo-controlled trial. The Lancet. 2007;370(9598):1560–1567. PMID 17825405
- Kobylewski S, Jacobson MF. Toxicology of food dyes. International Journal of Occupational and Environmental Health. 2012;18(3):220–246. PMID 23026007
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