How Much Vitamin A Do We Need Each Day?
Vitamins A performs many functions essential for life and health. Vitamins are classified according to their solubility, and vitamin A is considered fat-soluble. Fortunately, this means that vitamin A is ingested with fats in the diet and is readily available from a variety of foods in a well-balanced diet.
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Recommended Daily Allowances
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Infants and young children especially need vitamin A for optimal health, growth and development. It is important for a mother to breastfeed exclusively during the first six months of life to increase her baby's vitamin A stores. This is necessary because most infants are born with low levels of vitamin A. As infants grow into young children, the recommended daily allowance does fluctuate due to the transition from breast milk to actual food. The RDA for infants up to 6 months is 1,333 international units, and for infants 7 to 12 months it is 1,667 IU. The RDA for children 1 to 3 years old is 1,000 IU, children 4 to 8 years old is 1,333 IU and for children 9 to 13 years old it is 2,000 IU. The recommended daily allowance for adolescents between the ages of 14 and 18 is 2,800 IU for both males and females.
Pregnant women need to increase their vitamin A intake through foods and/or supplements. Women who are pregnant and 18 years and younger should consume 2,500 IU daily. Woman who are pregnant and 19 years and older require 2,567 IU. Adolescent women who are breastfeeding should consume 4,000 IU, while an adult breastfeeding woman needs 4,333 IU. The RDA for both adult men and women is 3,000 IU.
Sources Of Vitamin A
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Vitamin A comes from two different sources. One source is found in vegetables and fruits and also is known as beta carotene. Beta carotene is always nontoxic in foods. It is abundant in yellow and orange vegetables and fruit. Green vegetables also are rich in beta carotene. Spinach and carrots hold the highest amount. The other dietary form of vitamin A is found mostly in animal liver and dairy products. This form of vitamin A is know as retinol.
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Benefits Of Vitamin A
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Vitamin A performs many critical functions, both preventive and therapeutic. Vitamin A helps keeps skin and mucus membrane cells healthy and stimulates immune system response, which helps fight infections. Vitamin A also enhances vision in low lighting. Another important function of vitamin A is that it acts as an antioxidant, helping to protect cells against cancer and other diseases.
Toxicity Of Vitamin A
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Vitamin A toxicity is very rare and mostly is associated with long-term consumption in excess of 10 times the RDA. Toxicity of vitamin A is known as hypervitaminosis. People who may be susceptible to this at lower doses include the elderly, pregnant women and alcoholics. It is possible to receive excessive amounts of vitamin A strictly from diet, so a tolerable upper-intake level has been set at 10,000 IU daily.
Vitamin A Deficiency
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Severe vitamin A deficiency is one of the leading causes of blindness in children. Over half a million children lose their sight each year due to severe vitamin A deficiency. Vitamin A deficiency also increases the risk of complications and death from measles, causes dry hair and skin, and results in broken nails.
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References
Resources
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