Foods differ in their relative amounts of lutein and zeaxanthin, with lutein generally being more abundant. Lutein is found in dark green leafy vegetables such as spinach and kale, as well as in sweet corn and egg yolks, whereas zeaxanthin is found in sweet corn, egg yolk, orange peppers (capsicums), persimmons, tangerines, mandarins and oranges.
Lutein and zeaxanthin are primarily extracted from marigold flowers (Tagetes erecta) for use in supplements and are available in either free or esterified form. The esters typically contain two fatty acid groups that must be cleaved by pancreatic esterases and their absorption requires higher levels of dietary fat.
Deficiency Signs and Symptoms
It has been suggested that zeaxanthin and lutein be considered conditionally essential nutrients because low serum levels or low dietary intake are associated with low macular pigment density and increased risk of ARMD.
Epidemiological studies have also found an association between low serum carotenoid levels, including lutein and zeaxanthin levels, with all-cause mortality, the risk of inflammatory polyarthritis, breast cancer, prostate cancer, colon cancer, cervical cancer, human papilloma virus persistence, type 2 diabetes and impaired glucose metabolism, chronic cholestatic liver diseases, Alzheimer’s disease and vascular dementia, and low fruit and vegetable consumption.
Carotenoids have also emerged as an excellent tissue marker for a diet rich in fruits and vegetables, and measurement of plasma and tissue carotenoids is considered to have an important role in defining optimal diets.