Proper and balanced, as we used to say, nutrition plays a very decisive and regulating role in the effective functioning of almost all organs and systems of the human body, including the eyes and vision.
There are many foods, and individual nutrients, that have been associated with good vision function, but also with eye health, such as age-related macular degeneration (AMD) and cataracts. At the same time, the lack of certain nutrients in the daily diet has been shown to negatively affect visual function. According to studies, about 760 per 100,000 people have impaired vision. The two most important causes of visual impairment in Western countries are cataracts and age-related macular degeneration (AMD). Both conditions are associated with diabetes, obesity and ageing.
Cataracts, glaucoma, diabetic retinopathy, dry eye, degenerative retinal lesions such as macular degeneration, are various pathological conditions related to the eyes and vision that often occur in combination with metabolic diseases such as obesity, diabetes mellitus and hypertension. In other words, they occur in diseases and pathologies related to metabolism and the quantitative and qualitative impact of nutrition on it. Thus, following a diet that contributes to the regulation of metabolic parameters (glucose levels, blood pressure), but mainly in conjunction with the acquisition and maintenance of a healthy body weight, can play an indirect role in the better health of our eyes.
Η vitamin A, either as retinol or pre-vitamin A (beta-carotene), is what we call the vitamin of vision. Its actions are varied and include, the formation of the light-sensitive substance of the eye called rhodopsin (or visual purple, a pigment of the eyes involved in night vision). It is the most important micronutrient in the diet for our eyes, since its deficiency leads from visual disturbance and dry eyes (from its deficiency in infants and children where the eyes become very sensitive to light, while the secretion of tears is limited), to degenerative conditions such as corneal ulceration, night blindness (poor adaptation to darkness), up to more serious conditions such as irreversible blindness. On the contrary, being a fat-soluble vitamin, it has toxic effects when we have excessive intake. One of the symptoms of this toxicity is double vision, which is the tendency of the eye to see objects twice.
In our diet we get vitamin A from fish, fish oils, liver, milk, egg yolk, dark green leafy vegetables (spinach, broccoli), fruits and vegetables with bright colours due to carotenoids (e.g. apricots, peaches, mangoes, citrus fruits, as well as coloured peppers, carrots, and sweet potatoes.
For the health of the eyes an important role is played by a category of nutrients called antioxidants. The ageing process, various inflammations, cigarette smoking and sunlight are a source of free radicals and require the dietary intake of oxidants.
Thus, the systematic intake of antioxidants, vitamins, trace elements and minerals (beta-carotene, ascorbic acid - vitamin C, lycopene, lutein and zeaxanthin), mainly through the diet or in special groups and cases in the form of dietary supplements seems to be a proper prevention and treatment of eye diseases, mainly related to age, such as cataracts.
Studies on the actions of antioxidants have shown that higher intakes of vitamins C and E, as well as lutein and zeaxanthin, which are found in high concentrations in the retina, can prevent or delay the development of some types of cataracts and macular degeneration.
We get these antioxidants from fruits and vegetables such as carrots and orange-yellow fruits (blueberries, berries, red grapes), citrus fruits, tomatoes (lycopene), and zeaxanthin and lutein from foods such as maize, yellow peppers, spinach and egg yolk. Of course, we should also not forget that the main source of antioxidant vitamin E is olive oil.
We all know the relationship between omega 3 fats, belonging to the long-chain polyunsaturated fatty acids, with blood lipids (triglycerides and cholesterol) and their protective effect on the heart. However, they also appear to play a protective role for the eyes and vision, since, for example, one of them, namely docosahexaenoic acid (DHA), is a key component of the retina of the eye, and also plays a role in cell differentiation, the development of nerve tissues and the formation of retinal nerve synapses.
Thus, the consumption of fatty fish rich in omega-3 fatty acids such as sardines, bream, salmon, tuna, trout, herring, mackerel, plays an important role in reducing macular degeneration. Also, a study of about 38,000 women and their dietary habits over ten years, published in the journal Archives of Ophthalmology, showed that eating these fish reduces the risk of vision loss in older women by up to 42% compared to those who eat less than one fish a week.
Apart from oily fish and the corresponding fish oils, omega 3 can also be obtained from nuts, flaxseed, snails and some vegetables found in the Greek flora, e.g. in Crete, such as endaracla (slippery cress).
In addition to the ACE vitamins, a protective role through our diet can also be played by some B vitamins of the B complex (which are the vitamins of the nervous system), such as folic acid, and their reduced intake can lead to optic neuropathy. These vitamins can be found in green leafy vegetables such as broccoli and Brussels sprouts, fruits, liver, fish, meat, whole grains, some nuts, eggs and dairy products.
Η vitamin D, which we get mainly from dairy products, eggs, butter, margarines, fish, and direct exposure to age-related radiation, is also related to vision. Lack of vitamin D or calcitriol is associated with vision abnormalities.
