Annatto (E160b): A Common Natural Colour Culprit

Annatto (E160b) is a plant-derived yellow-orange colour found in cheese, butter and snacks, and a recognised trigger of hives in some people. What it is, who reacts, and where it hides.

What it is

Annatto is a natural yellow-orange colour extracted from the seeds of the achiote tree. Its active pigments are bixin (oil-soluble) and norbixin (water-soluble). On labels it appears as Annatto, Bixin, Norbixin or E160b. It is one of the oldest natural food colours and is the classic reason a “white” cheese like Red Leicester is orange.

Who reacts, and how it shows on the skin

Annatto is a good example of a natural additive that is not automatically gentle. It is a recognised, if uncommon, cause of hives (urticaria) and angioedema (swelling), and it can aggravate existing chronic hives. Most reactions appear to be pseudo-allergic, but occasional antibody-driven cases have been reported. Reactions tend to show within a few hours of eating a coloured food.

Where it hides

Coloured hard cheeses (Red Leicester, some Cheddar and double Gloucester), butter and margarine, custards, smoked fish and smoked cheese, snack foods, cereals, and some breaded or battered products. Look for Annatto, Bixin, Norbixin or E160b on the label.

What to do if you think you react

Cheese and dairy are the usual hiding places, so start there in a food-and-skin diary. Uncoloured versions of the same products (a pale, undyed Cheddar, for example) make an easy swap to test the link. If reactions are frequent, involve a GP or allergist, and treat any rapid swelling or breathing difficulty as an emergency.

Check it against your own list

A free scanner like Yuka gives a packaged product a general health score, a useful broad read, though that verdict is the same for everyone rather than tuned to your skin. Fig is genuinely good if you are managing a defined eating pattern. To check a product against the specific things that make your skin react, a personal-list app like ClearaScan lets you save your 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 that caused it, 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.)