Canthaxanthin

Canthaxanthin is an orange-red keto-carotenoid found naturally in mushrooms, crustaceans, and certain fish. Synthetically produced for food use, it provides an intense orange-red colour. Its most commercially significant application is as a feed additive for farmed salmon and trout, where it produces the characteristic pink-orange flesh colour consumers associate with fresh salmon. It is also used as a colorant in confectionery and certain food products.

JECFA's ADI is 0.03 mg per kilogram body weight per day, established in 1970 and kept low due to evidence that supplemental canthaxanthin causes crystal deposits in the retina of the eye (canthaxanthin retinopathy). This condition, observed in humans taking high-dose canthaxanthin supplements for tanning purposes, is reversible upon cessation but raised significant concern. The EU sets strict maximum limits on its use as a food additive and has banned its use as a tanning supplement.

Canthaxanthin is approved in the EU as a food additive at restricted levels, and is permitted in most global markets as a feed additive for salmon and poultry. As a food colorant it is primarily encountered in products where salmon-like colour is desired. Consumers eating farmed salmon regularly are exposed to canthaxanthin through the fish flesh, though at levels well below those that caused retinal effects in supplement studies. The key safety boundary is clear: food use at regulated levels is considered acceptable, while high-dose supplemental use is not.