Vitamin A

Definition Vitamin A is a generic term for a large number of related compounds Retinol (an alcohol) Retinal (an aldehyde) Retinoic acid Carotenoids

Function Vision Regulation of gene expression Maintenance of epithelial tissue Immunity Growth and development Red blood cell production Prevention of cancer

Males: mcg/day (IU/day) Females: mcg/day (IU/day) Recommended Dietary Allowance (RDA) for Vitamin A as Preformed Vitamin A (Retinol) Life Stage  Age  Males: mcg/day (IU/day) Females: mcg/day (IU/day)  Infants  0-6 months  400 (1333 IU) 7-12 months  500 (1667 IU)  500 (1667 IU) Children  1-3 years  300 (1000 IU) 300 (1000 IU) 4-8 years  9-13 years  600 (2000 IU) Adolescents  14-18 years  900 (3000 IU) 700 (2333 IU) Adults  19 years and older  Pregnancy  18 years and younger  -  750 (2500 IU) 19-years and older 770 (2567 IU) Breastfeeding  1,200 (4000 IU) 19-years and older  1,300 (4333 I

Good dietary sources of vitamin A Best sources include: beef liver carrots (as beta-carotene) mustard greens (as beta-carotene) eggs apricots (as beta-carotene) Note that beta-carotene is much less toxic in higher doses than is the preformed animal forms of vitamin A

Food Serving Vitamin A, RAE Vitamin A, IU Retinol, mcg Retinol, IU Cod liver oil 1 teaspoon 1,350 mcg 4,500 IU Fortified breakfast cereals 1 serving 150-230 mcg 500-767 IU Egg 1 large 91 mcg 303 IU 89 mcg 296 IU Butter 1 tablespoon 97 mcg 323 IU 95 mcg 317 IU Whole milk 1 cup (8 fl ounces) 68 mcg 227 IU 2% fat milk (vitamin A added) 134 mcg 447 IU Nonfat milk (vitamin A added) 149 mcg 500 IU Sweet potato 1/2 cup, mashed 959 mcg 3,196 IU Carrot (raw) 1/2 cup, chopped 385 mcg 1,283 IU Cantaloupe 1/2 medium melon 466 mcg 1,555 IU Spinach 1/2 cup, cooked 472 mcg 1,572 IU Squash, butternut  572 mcg 1,906 IU

Quantity Bioconverted to Retinol Retinol activity equivalency (RAE) ratios for beta-carotene and other provitamin A carotenoids Quantity Consumed Quantity Bioconverted to Retinol  RAE ratio  1 mcg of dietary or supplemental vitamin A  1 mcg of retinol*  1:1  2 mcg of supplemental beta-carotene  1 mcg of retinol  2:1  12 mcg of dietary beta-carotene  12:1  24 mcg of dietary alpha-carotene  24:1  24 mcg of dietary beta-cryptoxanthin 24:1 *One IU is equivalent to 0.3 mcg of retinol, and one mcg of retinol is equivalent to 3.33 IU of retinol.

vitamin A deficiency Symptoms Dry, hard skin Dry cornea and eventual blindness (Xerophthalmia) Night blindness (insufficient retinal for rhodopsin formation) Impaired immune function Deficiency also causes a decrease in appetite and poor growth

Cause of deficiency Insufficent intake(poverty,low income,…) Lack of food sources of V.A Low fat diet Malabsorption(surgery,parasite,…) Increasedneed(pregnancy,breastfeeding,…) Insufficent Supplemental feeding Infectious disease

Deficiency in children: 250 millions preschool children have subclinical deficiency The most incidencecause of blindness in developing countries(500000 children in year) If 1% children(2-6 years old)with night blindness or 10% children (6 months-6 years )had serum retinol below 7%micromol/l that population had health problem. Improve of V.A level in infant lead to decrease of 23% mortality

Control of VADD 1.Breastfeeding 2.Supplementation 3.Fortification 4.Food variety 5.Control of infectious disease&parasite

Supplement in severeV.A.D populatin Infant(<6months) 50000IU (not fed breastmilk or their mothers not take V.A supplement) Infant(6-12months ) 100000IU (every 4-6 months) Children(>1 year) 200000IU Children +1 mega dose (withmeaslse,diahrea,pneumonia& severe malnutrition) Mothers +1 mega dose (during 8 week after delivery)

Supplement in low V.A.D populatin Children(<2 years) 1500IU/daily Pregnancy 500IU/daily (from4 months- delivery) 2500IU/weekly

Toxicity Symptoms nausea, headache, fatigue, loss of appetite, dizziness, and dry skin, in pregnancy birth defects Signs of chronic toxicity dry itchy skin, loss of appetite, headache, and bone and joint pain Severe hypervitaminosis A liver damage, hemorrhage, and coma

Tolerable Upper Level of Intake (UL) for Preformed Vitamin A (Retinol) Age Group  UL in mcg/day (IU/day) Infants 0-12 months  600 (2,000 IU)  Children 1-3 years  Children 4-8 years  900 (3,000 IU)  Children 9-13 years  1,700 (5,667 IU)  Adolescents 14-18 years  2,800 (9,333 IU)  Adults 19 years and older  3,000 (10,000 IU)