Application of nutrigenomics in eye health.

This paper reviews recent findings on the implication of nutritional and genetic factors in age-related eye diseases: age-related macular degeneration (AMD; a degenerative disease of the retina) and cataract (opacification of the lens). Because of direct exposure to light, the eye is particularly sensitive to oxidative stress. Antioxidants, such as vitamin E, C or zinc, clearly have a protective effect in AMD and probably in cataract. In addition, two carotenoids, lutein and zeaxanthin, may play a more specific role in the eye: they accumulate in the retina, where they form the macular pigment, and in the lens. Their role is probably to filter out phototoxic blue light and to quench singlet oxygen. Finally, docosahexaenoic acid (an omega-3 polyunsaturated fatty acid) is particularly important for the retina, where it exerts structural, functional and protective actions. Besides, these diseases are strongly influenced by genetics, as demonstrated by familial and twin studies. The apolipoprotein E4 allele is associated with a reduced risk of AMD, while an association of AMD with complement factor H polymorphism has recently been demonstrated. Nutrigenomics, by studying the interactions between genetic variability and nutritional factors, represents a new challenge in order to account for interindividual variations in disease susceptibility. Such potential interactions are presented.