Macula protection

Several studies have linked lutein to a lower risk for eye, skin and other health disorders, probably through its antioxidant activity. Lutein is apparently metabolized to zeaxanthin, an isomer, and several other compounds which protect the macula from ultraviolet radiation. The suggestion is that lutein may play a positive role in reducing macular degeneration. Other reports have linked lutein to a reduction of risk of cancer.13 Regardless, lutein is currently being promoted as an important dietary supplement. 

P-carotene is only one of many antioxidants, which can be detected in the skin. Other carotenoids, for example, lutein and zeaxanthine, are preferentially found in the macula lutea, the so-called yellow spot in the eye. Here, carotenoids are subject to a metabolism typical for that tissue, which cannot be found in other tissues (e.g., formation of meso-zeaxanthine). In addition, they can specifically be absorbed into the macula. In the macula, they protect the retinal pigment epithelial cells against oxidative damage from UV light. Indeed, these two carotenoids can be protective against age-dependent macula degeneration. 

As a result, the lens and macula are prone to damage, especially without adequate eye protection. In addition to appropriate external protection (e.g., sunglasses), the eye requires an efficient internal antioxidant system. In this regard, Galileo apparently became blind after repeatedly observing the sun. Centuries later, in 1912, an estimated 3500 Germans suffered visual impairment after watching a solar eclipse. 

G4. Gerster, H., Review Antioxidant protection of the ageing macula. Age Ageing 20,60-69 (1991). 

AO/FRS [dietary vitamin protects visual macula by absorbing blue light] active against age-related macula degeneration (leading cause of irreversible blindness)... 

Skin afflictions from cercarias involve the epidermis because cercarias seem unable to penetrate beyond the derma. Initial itching is followed by an urticarial eruption which resolves within about 0.5 h, leaving maculae after a few hours, these transform into very itchy papules. The dermatitis resolves in 1-2 weeks. Prevention is only by individual protection, wearing overall wet suits, while environmental clean-up is required to solve the problem. Dermatitis from cere-... 

Lutein (6) and Zeaxanthin (9) in Kiwifruit Improvement and Protection on Human Macula and Retina... 

Meso-zeaxanthin is a xanthophyll that is not found within most foods but is present in some types of seafood [30, 55]. It is found to reach a maximum level in the central macula, where L levels reach a minimum [9]. This suggests that it may have some specific function at the macula. There may be a functional relationship between L and MZ within the central macula, as there is an inverse relationship between the two xanthophylls in terms of concentration at that location. Meso-zeaxanthin may be more effective than L at some essential role within the central macula and may not be needed in the peripheral retina. This suggests some kind of protective function in ARMD. It may also be that L is oxidized within the central retina, and then reduction results in its conversion to MZ [9]. The evidence suggests that there are specific mechanisms or biological pathways in place for the craiver-sion of L to MZ within the central macula. 

In summary, the fact that L and Z are selectively absorbed at the macula and the fact that L is likely to be converted to MZ at the fovea suggest some specific roles and have prompted interest in the possible functions of these carotenoids at that location. These functions may include screening of photooxidation inducing blue wavelengths of light, scavenging of free radicals, and also protection of RPE cells. 

The carotenoid lycopene has been reported to lower the risk of prostate cancer, but the evidence for a relationship between carotenoid intake and the risk of other cancers is conflicting. Increased intake of lutein and zeaxanthin may help to delay or prevent age-related maculopathy, because these carotenoids are concentrated in the macula and are likely to be very important in local protection of the lipid-rich retina. To date, however, epidemiological findings point to health benefits of foods containing carotenoids, and the influence, if any, of individual carotenoids remains to be established. 

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