carotenoids are found in many plants, algae, and bacteria. Carotenoids act as antioxidants within the body, protecting against cellular damage, the effects of aging, and even some chronic diseases. These beneficial compounds cannot be synthesized by humans or animals, diet is the only way to get them. There are well over 600 known carotenoids, with beta-carotene, alpha-carotene, lutein, zeaxanthin, lycopene, and astaxanthin being the most common.