The pigment responsible for giving seafood and crustaceans their pink to red hue, astaxanthin acts as a powerful antioxidant. It belongs to the carotenoid nutrient family -- the same one that includes beta carotene, a source of vitamin A. Astaxanthin isn't an essential nutrient, but it can benefit your health. You'll find it in several foods, primarily of marine origin, including seafood, microalgae and yeast.
Microalgae and Yeast
The most potent naturally occurring source of astaxanthin may be Haematococcus pluvialis, a very small algae, or microalgae, found in marine environments. Although humans don't regularly consume it on its own, many high-dose supplements come from this microalgae. A yeast, Phaffia rhodozyma, also generates substantial amounts of astaxanthin and is used to create supplements.
Salmon is a potent food source of astaxanthin, ranging in content from 4 to 40 milligrams per kilogram. The highest concentrations can be found in Pacific salmon, relative to Atlantic salmon. Fish that have developed in the wild may also have higher concentrations than their farmed counterparts.
Generally, seafood with a red to pink hue when raw or cooked may be a source of astaxanthin. For instance, although shrimp may have a greyish-blue colouring when raw, it transitions to vibrant pink when cooked. A few potential sources of astaxanthin include trout, krill, lobster, crabs, shrimp and crayfish.
Factors That Can Affect Astaxanthin Content
Astaxanthin, like many compounds in food, is sensitive to environmental stress. Long-term exposure to air and light can decrease astaxanthin concentration, as can contact with heat. Storage in airtight containers in dark places and minimizing cooking time may help reduce astaxanthin degradation in food.