Did You Know Annatto Is a Hidden Natural Colour Culprit?
Annatto (E160b) is a natural orange colour that turns up in cheese, butter and snacks, and quietly triggers hives in some people. Where it hides, why 'natural' does not mean safe, and how to spot it on a label.
The fact, stated plainly
When people think “food colours and skin”, they picture bright synthetic sweets. But annatto (E160b), a natural yellow-orange colour from the achiote seed, is a quieter culprit. It is the reason a cheese like Red Leicester is orange, and it is a recognised, if uncommon, trigger of hives and swelling. You can read more in our annatto (E160b) profile.
Why it happens
Annatto’s colour comes from two pigments, bixin and norbixin, extracted from the red coating around achiote seeds. In sensitive people these can prompt an urticarial reaction, hives, itching and sometimes swelling, in the hours after eating. The exact mechanism is not fully settled, and reactions appear to be uncommon, but annatto has a longer track record than most as a colour linked to hives. Crucially, being plant-derived makes no difference to the skin that reacts to it. “Natural” describes the source, not how your body responds.
Part of the reason annatto slips through is expectation. Most people who watch out for food colours are watching for the bright synthetic ones in sweets and fizzy drinks, so a soft orange in a wholesome cheese or a pat of butter simply does not register as a “colour” at all. That blind spot is exactly what lets a recognised, if uncommon, trigger keep catching the same people out.
Who it affects most
People whose skin reacts to food colours generally, and anyone with chronic hives linked to food additives. Because annatto is so often assumed to be harmless, it tends to catch out exactly the people who are careful about the synthetic dyes but never think to check a “natural” colour. Children who react to coloured foods can be affected too, since annatto is common in dairy and snacks.
How to spot it on a label
- Look for annatto, E160b, or its pigments bixin and norbixin in the ingredients list.
- Check the foods where it hides most: coloured cheeses, butter and margarine, custards, snack foods, smoked fish and some cereals.
- Do not rely on “no artificial colours” claims. Annatto is natural, so a product can carry that claim and still contain it.
- Uncoloured versions of the same product are the quickest test. A pale, uncoloured cheddar instead of an orange one removes the annatto while keeping the food.
What to do about it
If colours flare your skin, add annatto (E160b, also bixin or norbixin) to your watch list alongside the synthetic dyes, and check cheese and dairy labels in particular. Swapping to uncoloured versions for a couple of weeks is an easy way to see whether it makes a difference. Keeping a short food-and-skin diary while you do this helps you separate annatto from the other things you might be eating at the same time.
When to see a professional
Occasional mild hives that settle on their own can usually be managed by avoiding the trigger and, if needed, an anti-histamine your pharmacist recommends. See your GP if hives are frequent, persistent or affecting daily life, and ask about a referral if they are hard to pin down. Any reaction that involves swelling of the lips, tongue or throat, or difficulty breathing, is a medical emergency and needs urgent care straight away.
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 annatto (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.)
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Common questions
What is annatto?
Annatto is a yellow-orange food colour made from the seeds of the achiote tree. On labels it appears as annatto, E160b, or its active pigments bixin and norbixin. It is the colour behind Red Leicester, many orange cheeses and some butters and snacks.
If it is natural, why does it cause reactions?
Natural does not mean non-allergenic. Annatto is a recognised, if uncommon, trigger of hives and swelling in sensitive people. The plant origin makes no difference to skin that reacts to it.
Which foods most often contain annatto?
Coloured cheeses such as Red Leicester and some cheddars, butter and margarine, custards, snack foods, smoked fish and some breakfast cereals. It hides in everyday, wholesome-seeming foods rather than obvious sweets.
How do I avoid annatto?
Read ingredient lists for annatto, E160b, bixin or norbixin, and check cheese and dairy labels in particular. Uncoloured versions of the same products, for example a pale cheddar rather than an orange one, make an easy swap.
Could it be annatto rather than the synthetic dyes I already avoid?
Yes. People who screen only for synthetic azo colours can be caught out by a natural one. If colours seem to flare your skin but you have ruled out the synthetics, annatto is worth adding to your watch list.