Nutrition and Eye Health
Despite being an extremely active field of research, ocular nutrition remains relatively unknown to both health professionals and patients. Downie et al. have shown that patients have high expectations when it comes to getting advice on their diet. Opticians appear to be good people to talk to on the topic. Physiopathological and epidemiological data has been accumulating for some twenty years or so. Lens opacification can lead to the development of cataracts.
Incidentally, this organ contains 50 times more vitamin C than plasma. Similarly, the macular pigment of the retina contains two carotenoids, lutein and zeaxanthin, which act as both blue light filters and in situ antioxidants. Eisenhauer et al. have produced an overview of dietary sources of lutein and zeaxanthin and their bioavailability. The foods with the highest levels are leafy vegetables, with spinach and kale leading the field followed by cabbage, lettuce, parsley – and pistachio nuts. Meanwhile, the bioavailability of the lutein and zeaxanthin in eggs is remarkable, despite the low levels contained.
Epidemiological studies have confirmed the relationship between lifestyle and the appearance of a number of eye diseases. One such is the Nurses’ Health Study, which has been reviewed by Kang et al. As well as smoking, which creates harmful oxidative stress, they have demonstrated an inverse relationship between cataracts and carotenoids and other antioxidant nutrients, and between age-related macular degeneration and carotenoids, in addition to other factors like low glycaemic load in interaction with genetic factors.
So, to be on the safe side, let’s make sure we eat healthily.