Important Facts About Vision Vitamins
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.
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.
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.
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 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.
The truth is that it is not possible to take all the vision vitamins on a daily basis. What is important is to ensure that one takes them as many times as possible within the week. Intake is determined by factors such as sex, age, pregnancy and lactation. Excessive of the vitamins may cause toxicity and due caution is, therefore, advised.
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.
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.
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.
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 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.
The truth is that it is not possible to take all the vision vitamins on a daily basis. What is important is to ensure that one takes them as many times as possible within the week. Intake is determined by factors such as sex, age, pregnancy and lactation. Excessive of the vitamins may cause toxicity and due caution is, therefore, advised.
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