Wednesday, August 7, 2013

The Importance Of Vision Vitamins

By Nita McKinney


Apart from improving eyesight, vision vitamins also play a very vital role in the prevention of certain eye diseases such as macular degeneration and cataracts. Of all the nutrients that are known to have these benefits, vitamin A is undoubtedly the most published. It will be worth noting that there are many other nutritional elements that are equally as helpful. These include, for example, vitamin C and b6 and elements such as selenium, magnesium and zinc. Such nutrients will be found in great quantities in foods such as oranges, leafy vegetables and pumpkins.

We will look at vitamin A in detail and understand what it is that it does at cellular level. Research has revealed to us that this vitamin is very important in the synthesis of a pigment known as rhodopsin. This pigment is found in high amounts on the retina which acts as a screen on which images from the environment are formed. Adequate levels of rhodopsin are needed to help one see better in dim light.

It is important to mention that vitamin A is made up of several components and is not one unit as is believed by many. The different components are made up of hydrocarbon molecules that are unsaturated. They include molecules such as carotenoids, retinol and retinal. Beta carotene is the most important carotene that has been identified yet. When retinal combines with a protein called opsin, the result is the molecule rhodopsin.

A deficiency in vitamin A may lead to various eye problems ranging from mild, moderate to severe manifestation depending on the chronicity of the deficiency. Lack of this crucial vitamin can either be primary or secondary. A primary deficiency is due inadequate intake of either provitamin A carotenoids (vegetables and fruits) or the preformed vitamin from dairy and animal products. This is the commoner form.

The secondary form of deficiency is as a result of malabsorption of lipids and deficient bile production and release. This is explained by the fact that the A vitamin is a fat soluble vitamin and therefore requires dissolution in fat in fat for it become functional in the body. As such, a low fat diet can predispose one to disease states related to deficiency of respective vitamins. Long term exposure to oxidants including cigarette smoke and alcohol intake can also lead to secondary insufficiency of vitamin A.

Night blindness is one of the commonest and earliest symptoms of deficiency. One of the causes of reduced vision is drying of the conjunctiva which takes place as the condition progresses. The normal secretory system is progressively replaced with hardened keratinised tissue. As keratin plaques are eroded progressively, more keratinisation takes place.

The antioxidant properties of vitamin C help protect the eye from damage due to radiation. This nutrient also helps in maintaining normal pressure, collagen and capillary integrity. Vitamin B6 helps maintain the structure and function of red blood cells found within the retina. A trace element such as zinc plays a key role in ensuring good vision. It is responsible for converting 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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