The eyes are our way with which we relate to the outside world. But the eyes, over the years, can also undergo diseases such as macular degeneration, diabetic retinopathy, glaucoma and cataracts that can cause progressive loss of vision. And what are the causes of these diseases? Certainly a part is due to aging, genetics and diseases such as diabetes but a key role is also played by oxidative stress. Oxidative stress results in an imbalance between free radicals and antioxidants, to the detriment of the latter. However, dietary choices can help reduce the risk of developing vision diseases. This is what emerges from a recent review published in the journal Heliyon by a team from Abia State University, Nigeria (Uchenna Ikonne et al, Heliyon, 2020).
Spices, fruits and vegetables contain substances capable of counteracting the damage of free radicals and inflammation, at the origin of eye diseases. The researchers analyzed, on the basis of previous studies, the beneficial effects that some substances can have on vision health. What emerged is that curcumin, the active ingredient in turmeric, is able to protect the retina by decreasing the markers of inflammation, it counteracts oxidative stress and increases antioxidant enzymes, which is useful in preventing cataracts and diabetic retinopathy. Quercetin, a substance found in red onions, apples, blueberries, broccoli, capers and elderberries, is able to inhibit glaucoma and cataracts and protects the cells of the pigment epithelium, which is the external layer of the retina responsible, among other things, to guarantee its nourishment and to participate in the regeneration processes of the photopigments of cones and rods. Epigallocatechin gallate is a powerful polyphenol abundant in green tea. Scientific studies have observed that this antioxidant substance performs a protective function on the photoreceptors of the retina, helps prevent glaucoma and inhibits the death of retinal ganglion cells. These cells have the task of transmitting visual information to the brain since their axons, or extensions, form the optic nerve. Resveratrol from dark grapes, berries and cranberries counteracts inflammation and damage from free radicals. Not only that, resveratrol improves blood flow with a beneficial effect on the vitality of the optic nerve. The lycopene of watermelon, cooked tomato, pink grapefruit and papaya helps delay the onset of cataracts, protects the cells of the pigment epithelium and has beneficial effects in case of diabetic retinopathy. Caffeine seems to have the ability to reduce intraocular pressure while lutein and zeaxanthine, two substances mainly contained in spinach, carrots and red grapes, improve visual performance and help prevent age-related macular degeneration of the retina. Finally, here is the role of vitamins, particularly vitamin C, found in citrus fruits, pineapple, cabbage and tomatoes, vitamin E, found in pumpkin, peanuts and sunflower seeds, and vitamin A, found in carrots, mango, papaya and oranges. Vitamin C counteracts free radical damage thanks to its powerful antioxidant action and reduces the risk of cataracts, vitamin E is anti-inflammatory and counteracts free radicals and vitamin A improves night vision. But what is important to emphasize is that the combination of these three vitamins, more than the vitamins taken individually, is able to reduce the risk of macular degeneration of the retina and neovascular macular degeneration, which is a vision pathology characterized by the formation of new blood vessels under the retina and the cause of a rapid decrease in vision.
In short, the health of sight also passes from the table!