Dietary intakes of lutein and zeaxanthin were associated with a decreased lung cancer risk in a six-year study in more than 58,000 Dutch men (3) while other studies did not show such association (see also beta-carotene).
Age-related macular degeneration (AMD)
As lutein and zeaxanthin are present in high concentrations in the center of the eye’s retina (‘macula’), where they are efficient absorbers of blue light, they may protect against light-induced oxidative damage, which is thought to play a role in the pathology of age-related macular degeneration (2). AMD is the leading cause of blindness in older adults, for which there is currently no cure.
Epidemiological studies provide some evidence that higher intakes of lutein and zeaxanthin are associated with lower risk of AMD (4).
However, several prospective cohort studies found no relationship between baseline dietary intakes or serum levels of lutein and zeaxanthin and the risk of developing AMD over time (5, 6, 7, 8).
To date, the available scientific evidence suggests that consuming at least 6 mg/day dietary lutein and zeaxanthin from fruits and vegetables may decrease the risk of age-related macular degeneration (9, 10, 11).
Whether the magnitude of the carotenoids’ protective effects is significant enough over time to meaningfully reduce the risk of acquired retinal disease can only be definitively answered by long-term studies. This is particularly difficult, however, when considering that degenerative diseases like AMD reflect the accumulation of damage accrued over many decades of life.
Cataracts
As light absorbers lutein and zeaxanthin may prevent the eye’s lens from ultraviolet light and oxidant damage, causing structural changes that result in the formation of opacities known as cataracts. As people age, cumulative damage to lens proteins often results in cataracts that are large enough to interfere with vision (1).
Four large prospective studies found that men and women with the highest intakes of foods rich in lutein and zeaxanthin were 18–50% less likely to require cataract extraction (12, 13) or develop cataracts (14, 15, 16).
Cardiovascular health
One study has suggested that lutein may play a role in atherosclerosis prevention: higher levels of lutein in the blood have been associated with less thickening of arterials walls (17). More studies are needed to clarify this relationship.