Vision vitamins are the nutritional elements that enhance eye sight. These include vitamin A, B6, C, selenium, trace elements such as magnesium and zinc among other nutrients. A variety of food containing vitamins include, among others oranges, carrots, pumpkin and leafy vegetables. Having enough of these food sources in the diet protects one from getting certain eye diseases such as cataracts and macular degeneration.
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.
It should be understood that vitamin A is not a single unit. Rather, it is made of several non-saturated hydrocarbons. These hydrocarbons include retinoic acid, retinol, retinal and other precursors known as carotenoids. Beta carotene is the most important of these carotenes. The retinal hydrocarbon reacts with a protein known as opsin to form rhodopsin. The resultant molecule helps in the achievement of scotopic (low light) and colour 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.
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.
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.
Vitamins C and B6 play a minor role but are still very important. Vitamin C is an antioxidant that protects the eye against the effects of irradiation. It also maintains capillary and collagen integrity and normal pressure. B6 vitamin ensures that the red cell structure is intact and this in turn contributes to proper functioning of the retina. The mineral zinc is involved in the conversion of beta carotene to active 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 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.
It should be understood that vitamin A is not a single unit. Rather, it is made of several non-saturated hydrocarbons. These hydrocarbons include retinoic acid, retinol, retinal and other precursors known as carotenoids. Beta carotene is the most important of these carotenes. The retinal hydrocarbon reacts with a protein known as opsin to form rhodopsin. The resultant molecule helps in the achievement of scotopic (low light) and colour 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.
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.
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.
Vitamins C and B6 play a minor role but are still very important. Vitamin C is an antioxidant that protects the eye against the effects of irradiation. It also maintains capillary and collagen integrity and normal pressure. B6 vitamin ensures that the red cell structure is intact and this in turn contributes to proper functioning of the retina. The mineral zinc is involved in the conversion of beta carotene to active 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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