Short-sightedness and astigmatism are becoming a global issue and the leading cause of visual impairment and blindness. One in five children in India have these kinds of eye problems. Moreover, age-related eye diseases, including cataract, diabetic retinopathy, glaucoma, and age-related mascular degeneration are getting predominant all over the world.
The eye is a most sensitive organ in our body. Poor eyesight reduces self-confidence and quality of life of an individual. In career front, it poses negative impact and a significant threat for employment opportunities. Light exposure or high metabolic rate induces oxidative damage due to stress, along with exposure to chemical and environmental toxins. These are the basic reasons for growing vision impairment cases all over the world. In 2002, the government of India collaborated with the World Health Organization and International Agency for Prevention of Blindness, to fight against untreated eye health issues. Evidence from clinical research revealed that nutritional intervention is one of the recognized measures to avoid the underlying cause of vision damage and can impede the progression of eye diseases.
Nutrients for Preventing Eye Disease
Negligence of early preventive initiation and inadequate nutritional balance are primary reasons for eye disease. There are certain essential nutrients which are identified for maintaining the integrity of eye functionality, such as vitamin C, Vitamin E, Vitamin A (β-carotene), zinc and copper. There is considerable awareness about the importance of these nutrients for eye health, but there is still an emergent need to know the exact dosing to obtain a significant effect. National Eye Institute of America has recommended a daily dosage of these nutrients for people having a higher risk to develop age-related macular degeneration. In general, the daily dosage of these nutrients is mentioned below. However, the daily requirement can vary from an individual’s perspective:
- Vitamin C – 425 mg
- Vitamin E – 400 IU
- Vitamin A – 28,640 IU
- Zinc – 69.6 mg
- Copper – 1.6 mg
All the nutrients follow some specific mechanism of action to prevent eye diseases and maintain eye health. Carotenoids, vitamin C & E, and zinc have potent anti-oxidant property; whereas omega-3 fatty acids provide an anti-inflammatory effect, which is effective to ameliorate the risk of age-related eye diseases.
Vitamin C is a water-soluble vitamin and has potent antioxidant property. Oxidative stress induces fundamental structural damage to the body, including protein, DNA, and RNA. This can be prevented by adding sufficient vitamin C in the diet. The metabolic rate in the eye is high and have the tendency to get intense oxidative damage. Vitamin C can be easily absorbed in the blood and reach the eye tissues and prevent oxidative damage. Sufficient vitamin C consumption also enhances production of other antioxidants including vitamin E. Different fruits and vegetables, such as orange, grapefruit, papaya, strawberries, blackberries, blueberries, broccoli, cabbage, tomato etc. are the naturally rich sources of vitamin C.
Light sensitive cells of the retina present in the inner structure of the eye play a major role in visual perception. The retina is made up of fatty acid and vulnerable to oxidative damage. Vitamin E is a potent antioxidant and acts as a free radical scavenger and prevent lipid oxidation. It also possesses vasodilatory effect by inhibiting platelet aggregation. Vitamin E prevents inflammation by regulating the immune system functioning. There are different natural food items like almonds, peanuts, wheat-germ oil, soybean oil, and sunflower oil which are good sources of Vitamin E.
β-carotene, lutein, and zeaxanthin are three important carotenoids essential for healthy eye-sight. The details of each of these carotenoids are described below:
β-carotene: β-carotene present in different dietary products, acts as a pro-vitamin A in our body and assists to maintain vitamin A level in blood plasma. Vitamin A is essential for preventing eye dryness and night blindness, which can occur in any age group. Lettuce, spinach, kale, carrot, apricots, broccoli, pumpkin, sweet potato, etc. are different fruits and vegetables which contain a sufficient amount of β-carotene. Individuals having a higher risk to develop lung cancer should avoid excessive intake of β-carotene.
Lutein and zeaxanthin: Lutein and zeaxanthin are two carotenoids which are collectively referred to as macular pigments. They are primarily present in the retina and lens of the eye. Any deficiency of these carotenoids can disturb the normal functioning of the eye. Although these two nutritional components are carotenoids, they do not act as pro-vitamin A. These carotenoids also possess the strong anti-oxidant property and decrease the risk of vision impairment. Dietary food items like Brussels sprouts, broccoli, sweet corn, peas, kale, lettuce, spinach are few major sources of lutein and zeaxanthin.
Omega-3 fatty acids
Eicosapentaenoic acid [EPA], docosahexaenoic acid [DHA] are two omega-3 fatty acids which have potent anti-inflammatory properties and can effectively reduce the risk of eye diseases and other related visionary disturbances. These two omega-3 fatty acids can prevent oxidative stress and improve vascularization. Omega three fatty acids assist to maintain the proper blood circulation in the retina. DHA is one of the primary fatty acids abundantly present in retina and assists to regulate thickness, permeability, fluidity, lipid-phase properties. Thus, DHA plays a significant role in photoreceptor-membrane functioning. Fish oil supplement is one of the most convenient ways to achieve the required amount of EPA and DHA. Besides maintaining eye health, it can also prevent cardiovascular diseases. Omega-3 fatty acids have a preventive effect against atherosclerosis.
Zinc is an essential mineral which can boost immunity and improve the functionality of the natural antioxidant of the body. It reinforces the eye functioning by upholding cell membrane structure. It also has a role in nerve signal transmission, which is essential for sense organ functionality. Therefore, adequate zinc containing foods like multigrain cereals, cooked chicken, yogurt, milk, cheese, corn flakes, cashew nuts, peanuts, and almond should be included in our daily food consumption list to fulfill the requirement of zinc.
Protein malnutrition is another major reason for vision impairment, apart from the insufficiency of these micronutrients and bioactive dietary ingredients. An egg in the plate every day, besides leafy green vegetables and colorful fruits, can help to retain strong eyesight. Research evidence support that 18 percent of cataract incidences can be reduced by regular intake of sufficient green vegetables and an egg. This regimen is highly recommended for children. Several dietary supplements are available in the market, but natural sources for nutrition are the most cost-effective measures to keep our eyes healthy.