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| Vitamin A By Charles Silverman Vitamin A comes from animal sources such as eggs and meat, and is present in the form of a precursor called beta-carotene , when manufactured by plants. Vitamin A is found in milk, cheese, cream, liver, kidney, cod and halibut fish oil. All of these sources, except for skim milk that has been fortified with vitamin A, are high in saturated fat and cholesterol. The vegetable sources of beta-carotene are fat and cholesterol free. The body regulates the conversion of beta-carotene to vitamin A, based on the body's needs. Sources of beta-carotene are carrots, pumpkin, sweet potatoes, winter squashes, cantaloupe, pink grapefruit,apricots, broccoli, spinach, and most dark green, leafy vegetables. The more intense the color of afruit or vegetable, the higher the beta-carotene content. Functions Vitamin A helps in the formation and maintenance of healthy teeth, skeletal and soft tissue, mucous membranes, and skin. It is also known as retinol, as it generates the pigments that are necessary for the working of the retina. It promotes good vision, especially in dim light. It may also be required for reproduction and lactation. Beta carotene, which has antioxidant properties, isa precursor to vitamin A. Recommendations Recommended daily allowances (RDAs) are defined as the levels of intake of essential nutrients that the Food and Nutrition Board judges to be adequate to meet the known nutrient needs of almost all healthy persons. The best way to get the daily requirement of essential vitamins is to eat a balanced diet that contains a variety of foods from the food guide pyramid. Side Effects Vitamin A deficiency can increase the susceptibility to infectious diseases, as well as cause visionproblems. When you are seriously deficient in vitamin A, your body suffers dire consequences: your bones, reproductive organs, skin, and your respiratory tract all begin to malfunction. Large doses of vitamin A can be toxic although you would have to take about 50,000 IU or more daily that's ten times the RDA for an extended period of time for you to develop signs of intoxication . They can also cause abnormal fetal development in pregnant women. Increased amounts of beta-carotene can turn the color of skin to yellow or orange. The skin color returns to normal once the increased intake of beta-carotene is reduced. |
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