Lutein and zeaxanthin, which are carotenoids found in the macula of the eye, have been shown to reduce the risk of cataracts and age related macular degeneration (ARMD).
Corn is the only good source of both lutein and zeaxanthin. Dark, leafy greens contain significant lutein, while two Brazilian fruits, piqui and buriti, contain zeaxanthin. Processed corn includes canned corn, corn meal, corn flour, and corn flakes. Corn foods include farofa, boiled corn, pamonha, curau, and polenta (fried and boiled). Chickens fed corn concentrate yellow carotene pigment in their yolks, muscle and skin.
The authors compared the availability of lutein and zeaxanthin in the above foods. Canned corn had the highest levels of zeaxanthin, beta cryptoxanthin and beta carotene. Corn flakes had high levels of zeaxanthin, and corn meal had the highest levels of lutein and good levels of zeaxanthin. Farofa had a drastic reduction of carotenoids, while curau, pamonha and polenta all had low levels of carotenoids. Raw corn had more carotene than cooked corn.
Oxidation is the cause of the loss of carotenoid activity during processing. This loss is reduced by the use of antioxidants and increased by heat, metals, light and enzymes.
CONCLUSION: Corn is one good source of the carotenoids lutein and zeaxanthin, which reduce the risk of cataracts and age related macular degeneration. However, processing and preparation greatly alter the levels of these carotenoids in foods. Besides rare fruits from Brasil, canned corn, corn meal and corn flakes are good sources of these carotenes.
NOTE: Pamonha is a traditional Brazilian dish made from corn and milk paste wrapped in banana leaves. Curau is a dessert, like custard, made from unripe green corn, milk and sugar. Polenta is similar to cornmeal mush.
Read a list of foods containing lutein and zeaxanthin.
To read the author’s abstract of the article click on the link to the author’s title of the article above.