Vitamin A and carotenoids for healthy eyes
Antioxidants are thought to reduce the risk of eye diseases such as macular degeneration and cataracts. Vitamin A is one of the important antioxidants. Animal sources such as liver and butter offer direct vitamin A, while vegetables and fruits contain carotenoids, which can be converted into vitamin A by human body. Some carotenoids such as lutein and zeaxanthin also add red and yellow pigments to plants and animals.
Vitamin A plays an important role in maintaining eye health. As mentioned above, vitamin A is indicated to decrease the incidence of macular degeneration and cataracts. Vitamin A deficiency may lead to xerophthalmia, accompanied by dry eye, corneal ulcers and swollen eyelids. Left untreated, night blindness can be caused. In developing countries, vitamin deficiency is a major contributor to blindness. And sufficient vitamin A prevents night blindness.
Daily allowance of vitamin intake has strict standards. People who drink or smoke need an extra amount of vitamin A than ordinary people. Tobacco affects the efficiency that human body absorbs vitamin A and drinking rapidly dissipates vitamin A that has been in the body. You’d better to choose fresh vegetables and fruits. If you are beyond fresh food, remember that frozen foods preserve vitamin A better than canning types.
Lutein and zeaxanthin are also proved by some studies that they decrease the rate of developing cataract and macular degeneration. Green, leafy vegetables such as spinach, kale and collard, and fruits as well as eggs yolks are rich in both lutein and zeaxanthin. Studies show that cooked vegetables contain lutein and zeaxanthin that are easier for absorption than raw types. Interestingly, scientists found out that lutein and zeaxanthin always appear together.
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