Healthnotes Newswire —Lutein and zeaxanthin, two nutrients found in fruits and vegetables, do not offer significant protection against early age-related vision loss, according to a study published this month in the American Journal of Epidemiology.

In this new study, 8,200 adults over the age of 40 were interviewed about their dietary habits. Each participant also underwent a physical exam, which included blood tests and assessment of visual health.

No consistent relationship was found between either dietary intake or blood levels of lutein or zeaxanthin and risk of macular degeneration, the leading cause of blindness in older Americans. Participants between the ages of 60 and 79 years with the highest dietary intake of lutein and zeaxanthin, however, were found to be 90% less likely to have the most advanced symptoms of macular degeneration compared with those subjects with low intakes of these nutrients. Macular degeneration has been estimated to affect as many as 7% of people over 75 years old.

Lutein and zeaxanthin belong to a class of nutrients known as carotenoids. There are several hundred known carotenoids, including beta-carotene and lycopene. Foods high in lutein and zeaxanthin include leafy green vegetables, corn, green peppers, carrots, oranges, and eggs. These carotenoids have an affinity for the part of the retina where macular degeneration occurs. Once there, they protect the retina from damage caused by sunlight.

The new study raises more questions than it answers. Although the authors tried to make their results as specific as possible to intake of specific nutrients, the possibility remains that their findings simply reflect the protective effect (or lack thereof) of fruits and vegetables on the eyes, rather than showing a specific effect of lutein or zeaxanthin. Also, it is unclear from this study why these carotenoids would protect against the worst symptoms of visual loss, but not offer consistent protection against the earlier stages. Until these questions are answered by studies of more sophisticated design, people seeking to protect their eyesight should consider loading up on fruits and vegetables. Spinach and kale eaters have been previously found to have a lower risk of macular degeneration. It appears too soon, however, to suggest taking supplemental lutein or zeaxanthin to prevent macular degeneration.