The Importance Of Vision Vitamins

By Nita McKinney


Vision vitamins are an important component of our everyday diet. Apart from the vitamin A which is widely known for its important properties, there are many others that play a central role in maintaining good eyesight. These nutritional elements include vitamin B6 and C and others such as selenium, zinc and magnesium among others. There are many different types of foods that contain many of these elements in different combinations. Examples include green leafy vegetables, oranges, carrots and pumpkins among others.

We will explore the benefits of vitamin A in more detail since it is the nutrient of greatest significance. The vitamin is involved in the synthesis of a pigment of the retina known as rhodopsin. Rhodopsin is necessary for dim vision. The other important role that this pigment plays is that it helps to keep the cornea moist through the maintenance of the integrity of related membranes.

The A vitamin is not a single unit as such but is composed of a group of hydrocarbons which are not saturated. These include retinoic acid, retinal, retinol and a number of vitamin A precursors (carotenoids). The most important among the pro vitamin A carotenoids is beta carotene. Retinal component combines with the protein opsin to form rhodopsin. The so formed light absorbing molecule is vital for both colour and low light (scotopic) vision.

Lack of vitamin A causes many eye problems whose severity varies depending on the period of time one is affected and the extent of deficiency. Such a deficiency will be caused by inadequate amounts of vitamin A in the diet for a long time. This is called primary vitamin A deficiency. Its prevention entails frequent intake of carotenoid containing foods such as fruits, vegetables and dairy products.

Secondary deficiency is commonly the result of impaired absorption of lipids and decreased production and release of bile. The A vitamin is fat soluble and will therefore require that there are enough lipids for it to be adequately absorbed. Cigarette smoking and prolonged alcohol use are the other risk factors that have been identified as contributing to insufficiency of this vitamin.

One of the earliest symptoms of deficiency is impairment of night vision. This is the result of dryness of the conjunctiva and replacement of thee secretory epithelium with keratinised (hardened epithelium). A vicious cycle ensues where the erosion of keratin plaques gives way to formation of more keratin. Eventually, the ability of the cornea to refract light is markedly reduced.

The other vitamins play a relatively minor role. Vitamin C has antioxidant properties which help protect the eye from irradiation. It is also important in the maintenance of capillary integrity and normal pressure. The B6 vitamin maintains red cell structure and function and thus ensures that the retina functions optimally. Zinc takes part in the conversion of beta carotene to vitamin A.

While it may not be practical to take all vision vitamins every day, it is advisable to take food supplements that contain the maximum number of essential vitamins in them. The amount of intake is also limited by factors such as age, sex, pregnancy and lactation. It is important to ensure that one takes just the right amount of nutrients to avoid toxicity and related complications.




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