Lutein and inflammation: a comprehensive review of its mechanisms of action

Lutein, a natural dihydroxy carotenoid and a member of the non-vitamin A carotenoids family, is abundant in yellow-colored fruits and green leafy vegetables such as spinach and lettuce. As the second most common type of carotenoid found in human serum, lutein offers a plethora of medicinal benefits, including anti-cancer, anti-inflammatory, and anti-oxidative properties. It is well-absorbed and systemically localized to the liver, lung, and retina, where it can cross the blood-retina barrier and accumulate in the macular pigment. Due to its anti-oxidative and singlet oxygen quenching properties, lutein is reported to reduce the risk of age-related macular degeneration (AMD). Higher concentrations of fasting plasma carotenoids and enhanced skin yellowing after lutein consumption indicate its presence in various regions of the human body, including the skin, breast, brain, and cervix. Lutein has remarkable benefits for neurodegenerative diseases, cardiovascular health, liver protection, and bone disease prevention. In the central nervous system (CNS), lutein supports brain homeostasis through its antioxidant and anti-inflammatory properties, increasing interleukin-10 (IL-10) and reducing tumor necrosis factor-α (TNF-α). It reduces the risk of coronary artery disease and exerts anti-inflammatory effects on peripheral blood mononuclear cells (PBMCs). Lutein protects against alcohol-induced liver damage by modulating the nuclear factor erythroid 2-related factor 2 (Nrf2)/heme oxygenase-1 (HO-1) signaling pathway. Additionally, lutein promotes bone health by enhancing mineralized bone nodule development and inhibiting osteoclast production, reducing bone resorption, and suppressing soluble receptor activator of nuclear factor kappa B ligand (RANKL). These multifaceted benefits make lutein a valuable agent in disease prevention and health promotion. This review discusses the comprehensive profile of lutein as a phytochemical activity, including anti-inflammatory, antioxidant, anti-cancer, hepatoprotective, neurological, and cardioprotective effects. Additionally, it discusses lutein’s beneficial impact on macular degeneration and eye diseases, showcasing its potential as a natural, plant-based therapeutic agent.