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Health Encylopedia

Vitamin A
Definition Vitamin A is a fat-soluble vitamin. 
Alternative Names   Vitamin A deficiency; Deficiency - Vitamin A  
Function 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 because it generates the pigments in the retina . Vitamin A promotes good vision, especially in dim light. It may also be required for reproduction and lactation. Beta carotene, which has antioxidant properties, is a precursor to Vitamin A.
Food Sources 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 fat '>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 a fruit or vegetable, the higher the beta-carotene content.
Side Effects Vitamin A deficiency can increase the susceptibility to infectious diseases, as well as cause vision problems . Large doses of Vitamin A can be toxic. 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.
Recommendations Recommended daily allowances (RDAs) are the levels of essential nutrients that the Food and Nutrition Board judges as 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