astaxanthine

Astaxanthin, sometimes spelled astaxanthine, is a keto-carotenoid pigment belonging to the xanthophyll family. It is responsible for the pink to red coloration seen in salmon, shrimp, krill, and flamingos, and is widely studied for its antioxidant properties. Chemically, astaxanthin has a C40H52O4 backbone with two terminal ionone rings bearing hydroxyl and keto groups, connected by a conjugated polyene chain. It occurs in nature in free form and as mono- or diesters with fatty acids, and is produced commercially from microalgae, most notably Haematococcus pluvialis, as well as other microorganisms and yeasts.

Natural sources and production

Astaxanthin is synthesized by certain algae and accumulates in organisms that consume algae, entering the marine food web. Commercial production often centers on the green unicellular alga H. pluvialis, which under stress conditions yields high concentrations of astaxanthin. It is then extracted and processed for use in supplements, animal feeds, cosmetics, and food products.

Uses and applications

In aquaculture, astaxanthin is added to feeds to impart the characteristic pink color to salmon, trout, and crustaceans and to support health. In human nutrition, it is sold as a dietary supplement and studied for potential effects on oxidative stress, inflammation, visual function, and skin health. It is also used as a cosmetic ingredient for its antioxidant properties and as a color stabilizer in some formulations.

Bioavailability and form

Astaxanthin is lipophilic, with absorption enhanced by dietary fats. In supplements, it appears as free astaxanthin or as mono- or diesters, and processing can influence bioavailability.

Safety and regulation

Astaxanthin is generally considered safe as a dietary supplement and food additive when used appropriately, though regulatory status and approved applications vary by jurisdiction. High intakes can cause harmless orange or pink discoloration of the skin or stools. Individuals with seafood allergies should exercise caution and consult healthcare professionals as needed.