Recent advances in carotenoid absorption, distribution, and elimination

Carotenoids are a class of pigments with antioxidant properties synthesized by photosynthetic and heterotrophic organisms. Humans can store carotenoids in their intact form or cleave them enzymatically to apocarotenoids such as vitamin A, a hormone-like nutrient with crucial roles in gene expression and vision. Clinical and preclinical studies suggest that the consumption of diets rich in carotenoids attenuate cardiometabolic diseases, some types of cancer, neurodegenerative disorders, and inflammatory conditions. The bioactive properties of carotenoids depend, at least in part, on their accumulation in target tissues. However, the pathways that drive carotenoid absorption, delivery, and accumulation in tissues remain largely uncharacterized. This review provides a critical overview of the experimental models utilized to monitor carotenoid homeostasis in mammals. We also delve into recent findings concerning carotenoid intestinal uptake, bodily distribution, cellular uptake, and intracellular trafficking. Finally, we discuss the physiological relevance of a fecal carotenoid elimination pathway that operates independently of carotenoid enzymatic cleavage. Establishing the players governing carotenoid biodistribution and elimination is essential to maximize the bioactive properties of carotenoids in humans to prevent chronic diseases.