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Lutein and zeaxanthin are found in high levels in foods such as green vegetables, egg yolk, kiwi fruit, grapes, orange juice, zucchini, squash, and corn. For some commercially available supplements, lutein is extracted from marigold petals. Lutein and zeaxanthin are carotenoids in the macular region of the retina of the eye (macular pigment), and thus lutein has been studied for its use in treating cataracts, preventing macular degeneration and retinal degeneration. Lutein and zeaxanthin also have antioxidant capabilities as well as the ability to trap short-wavelength light. The potential for carotenoids, including lutein, to play a preventing role in cardiovascular disease and cancer was recognized in the 1990s. Most of the information surrounding lutein is based on blood and/or dietary intakes of lutein compared with disease states (e.g. cancer, eye disorders, lung function, muscle soreness, obesity, and pre-eclampsia). More evidence is needed before recommendations can be made in these fields.
Riboflavin is a water-soluble vitamin, which is involved in vital metabolic processes in the body and is necessary for normal cell function, growth, and energy production. Small amounts of riboflavin are present in most animal and plant tissues. Healthy individuals who eat a balanced diet rarely need riboflavin supplements. Especially good dietary sources of riboflavin are milk (and other dairy products), eggs, enriched cereals/grains, meats, liver, and green vegetables (such as asparagus or broccoli). Intake may be lower in vegetarians compared to non-vegetarians. Riboflavin is often used as a tracer of medication compliance in the treatment of patients with alcohol dependence, mental disorders, and other conditions. Urinary riboflavin levels may be measured in order to determine the level of compliance.