There is copious evidence for the role of two particular antioxidants - lutein and zeaxanthin - in maintaining eye health. Carotenoid composition varies between internal organs, suggesting selective uptake or metabolism of these nutrients. These two are the only carotenoids found in the eye. Recent research suggests that the body absorbs and then deposits lutein in two different parts of the eye - the macula (the bright yellow spot at the centre of the retina) and the lens.

Evidence suggests that supplementation with lutein and zeaxanthin can help retard the process of age-related macular degeneration, or AMD (Am J Clin Nutr, 1995; 62 [6 Suppl]: 1448S-61S). In one study, the incidence and severity of AMD was reduced by 43 per cent through supplementation (JAMA, 1994; 272: 1413-20).

Lutein and zeaxanthin are abundant in a wide range of foods, including mango, papaya, oranges, peaches, kiwi, spinach, squash, peas, lima beans, green beans, broccoli, brussels sprouts, cabbage, kale, lettuce, prunes, pumpkin, sweet potato and honeydew melon. One study found that changes in diet - for instance, adding corn and spinach - not only elevated levels of lutein and zeaxanthin, but also improved the density of the macular pigment (Invest Ophthalmol Vis Sci, 1997; 38: 1795-801).