The carotenoids lutein and zeaxanthin were the most strongly associated with reduced risk of macular degeneration (MD). These are obtained primarily from dark green, leafy vegetables such as spinach, collard greens, kale, mustard greens, and turnip greens. Eating spinach and collard greens five or more times a week was found to noticeably reduce the risk of MD.
In addition to their antioxidant mechanism, lutein and zeaxanthin may help to protect the retina for any or all of the following reasons:
- They may protect against photodamage of the retina by filtering out blue light, which is not stopped by the cornea and lens, and which can damage the retina over time
- They may protect against peroxidation of fatty acids in the photoreceptor membrane
- They may protect the blood vessels that supply the macular region.
Lutein and zeaxanthin absorb best when taken with fat. For maximum absorption take supplements with any meal that contains fat or take along with any fatty acid supplements. The typical dose of lutein is between 10 and 20mg per day, and zeazanthin 1 to 4mg or higher per day.