Carotenoids such as lutein and zeaxanthin are tetraterpenoid pigments synthesized by plants and algae, responsible for yellow-orange coloration in fruits, vegetables, and flowers. They function as antioxidants protecting against oxidative stress and play critical roles in photosynthesis by dissipating excess light energy. In human nutrition, these xanthophylls accumulate in the macula of the eye, filtering blue light and reducing risk of age-related macular degeneration. Lutein and zeaxanthin are lipophilic molecules with conjugated double bonds conferring their color and radical-scavenging properties. They are commonly obtained from spinach, kale, and marigold flowers and are used as food colorants and dietary supplements. Their bioavailability increases when consumed with dietary fats.