Characterization of astaxanthin isomers in different types of salmon filets and human plasma after salmon consumption

Astaxanthin, a marine carotenoid with antioxidant and anti-inflammatory properties, exists in various isomers in salmon. Despite salmon being a key dietary source of astaxanthin in American diets, the isomer contents across salmon types, processing methods, and human plasma post-consumption remains underexplored. Using mass spectrometry, we analyzed astaxanthin isomers, EPA, and DHA in wild and farmed salmon, processed salmon products, and human plasma following a feeding study. Results showed higher levels of 3S,3'S-all-trans-astaxanthin, EPA, and DHA in wild versus farmed salmon. Cooking did not affect 3S,3'S-all-trans-astaxanthin levels, but they were lower in processed forms like canned salmon. Plasma concentrations of 3S,3'S-all-trans-astaxanthin increased significantly in humans after consuming a Mediterranean diet with two servings of farmed salmon per week for five weeks. Notably, 13-cis-astaxanthin, but not 9-cis-astaxanthin, was detected in plasma. These findings demonstrate that food processing and farming practices affect astaxanthin levels, and that plasma astaxanthin concentrations reflect dietary salmon intake.