Progress in the bioavailability of natural astaxanthin: Influencing factors, enhancement strategies, evaluation methods, and limitations of current research

Abstract

Background

Natural astaxanthin is a dietary carotenoid with distinguished antioxidant properties, but the low bioavailability limits its applications in food field.

Scope and approach

Based on the discussion of astaxanthin molecular structure, transport proteins, food matrix, and gut microbiota that affect the oral bioavailability of astaxanthin, this review outlines the primary strategies for enhancing its bioavailability. Additionally, we summarize common experimental methods for evaluating astaxanthin bioavailability to optimize its food formulations.

Key findings and conclusions

Strategies to enhance astaxanthin bioavailability, such as structural modifications, delivery systems, and modulation of gut microbiota and the expression levels of intestinal epithelial transport proteins, offer promising avenues for functional food development. Particularly, delivery systems are the most effective, improving oral bioavailability by enhancing digestive stability, controlled release, migration ability, and intestinal mucosal permeability of astaxanthin. However, several challenges, including material safety, stability, high costs, as well as the complexity and consistency of the preparation process, limit delivery systems large-scale application. Furthermore, current bioavailability evaluations primarily relied on in vitro digestion models, with limited in vivo studies addressing absorption and metabolism. Incorporating transport protein activators or prebiotics into delivery systems holds promise for synergistic effects on gut microbiota and epithelial transport mechanisms, further improving astaxanthin bioavailability. Advancing studies on bioavailability in animals and developing realistic gastrointestinal simulators, such as dynamic digestion or microfluidic systems, are essential for strengthening in vitro/in vivo correlations. These efforts will provide a robust foundation for developing effective delivery systems and optimizing functional food formulations of astaxanthin.