What is lutein?

As humans are unable to synthesize carotenoids, they must ingest plant products or animal products that have been enriched with carotenoids to meet daily health recommendations. The six most commonly ingested carotenoids in the human diet can be separated into two groups:
(1) Provitamin A carotenoids (alpha-carotene, beta-carotene, and beta-cryptoxanthin)
(2) Non-provitamin A carotenoids (lutein, lycopene, and zeaxanthin).

Lutein is one of the most prevalent carotenoids in nature and in the human diet. In ripe bananas, one of the major carotenoids is lutein. Lutein abundantly found in banana peel and belongs to xanthophyll's family.

Like the other carotenoids, lutein has been shown to have antioxidant effects. Lutein and zeaxanthin are constituents of the pigment of the eye. A low density of this pigment in the macula of the eye may increase the risk of the disorder macular degeneration, possibly because it permits greater blue light damage.

Lutein is likely neuro-protective through its role as an antioxidant, an effect that may apply globally and not be limited to specific regions or cognitive domains.

The brain is especially vulnerable to free radical attack due to its high polyunsaturated fatty acid content and high metabolic activity. Lutein is differentially localized to membrane domains rich in polyunsaturated fatty acids including DHA, and therefore is well positioned to block oxidation of these vulnerable lipids.
What is lutein?