5PROVITAMINS“An inactive form of a vitamin that the body can convert into an active use-able form.Example: CarotenoidPrecursor of Vit A in foods of plant origin. Present in many fruits and vegetables.
6Major Role of Vitamins: Antioxidants CoenzymesVit E B-VitaminsVit C VisionCarotenoids Vit ABone Health Blood ClottingVit D Vit KVit K
7VITAMIN-A (The Retinoids) Three active (03) Forms:Retinol The alcohol form (KEY PLAYER)(reproduction& bone health)Retinal The aldehyde form(night & color vision)Retinoic acid The acid form(cell growth & differentiation)
8Vitamin A interconversions RetinalRetinoic acidRetinol
9STORAGE &TRANSPORT Liver 90 % Adipose tissues Lungs & kidneys 10% (stored as retinyl esters)Transported by retinol binding protein (RBP)Serum range of RBP = mcg/dL.
10SOURCES OF VITAMIN-A Animal food 50% (as preformed Vit-A) Cod liver oil, Milk fat, Meat, Eggs,Fortified foods like Margarine.Fruits and Vegetables %(as provitamin-A , carotenoids)Carrots,Spinach,Broccoli,Potatoes,Apricot,Mangoo.Papaya,Pumpkin
11MEASURING UNIT RAE (Retinol Activity Equivalent) 1 RAE = 1 microgram Retinol= 12 microgram beta carotene= 24 microgram carotenoids
12RECOMMENDED DAILY ALLOWANCE MALE microgram RAEFEMALE microgram RAEPREGNANT WOMEN microgram RAELACTATING WOMEN microgram RAEINFANTS microgram RAE
13FUNCTIONS OF VIT-A Vit-A and Vision ( Retinal) Vit-A and cell differentiation (Retinoic acid)Vit-A and immune functions (Retinoic acid)Vit-A and reproduction (Retinol+Retinal)Vit-A and bone health (Retinol+Retinal+Retinoic)
15VITMIN-A DEFICIENCYEYE: The signs of vitamin A deficiency are predominantly ocularNightblindnessConjunctival xerosisBitot’s spotsCorneal xerosisKeratomalaciaXEROPHTHALMIA: (dry eyes) includes all ocular manifestations ranging from night blindness to keratomalacia.
16VITMIN-A DEFICIENCY NIGHTBLINDNESS CONJUNCTIVAL XEROSIS Lack of vitamin A first causes night blindness or inability to see in dim light.CONJUNCTIVAL XEROSISThis is the first clinical sign of vitamin A deficiency. The conjunctiva becomes dry and non-wettable.
18VITAMIN- A DEFICIENCY BITOT’S SPOTS Bitot’s spots are triangular, pearly-white or yellowish, foamy spots on the bulbar conjunctiva on either side of the cornea. They are frequently bilateral. Bitot’s spots in young children usually indicate vitamin A deficiency. In older individuals, these spots are often inactive sequelae of earlier disease.
20VITAMIN-A DEFICIENCY CORNEAL XEROSIS The cornea appears dull, dry and non-wettable and eventually opaque. It does not have a moist appearance. In more severe deficiency there may be corneal ulceration. The ulcer may heal leaving a corneal scar which can affect vision.
22VITAMIN-A DEFICIENCY KERATOMALACIA Keratomalacia or liquefaction of the cornea is a grave medical emergency. The cornea (a part or whole) may become soft and may burst open. The process is a rapid one. If the eye collapses, vision is lost.
24EXTRA-OCULAR MANIFESTATIONS SKIN: Follicular Hyperkeratosis.( goose flesh)GROWTH :retardation, bone deformities.IMMUNE FUNCTION:Increased morbidity and mortality due to respiratory and intestinal infection.decreased sperm production,female infertility.
25TREATMENTAll the early stages of xero-ophthalmia can be reversed by administration of a massive oral dose (200,000 IU or 110 mg) of Retinyl Palmitate on two successive days.Children with corneal ulcers should receive vitamin A whether or not a deficiency is suspected.
26EPIDEMIOLOGYAn estimated 250 million preschool children and 19 million pregnant women are vitamin A deficient globally.An estimated to vitamin A deficient children become blind every year, half of them dying within 12 months of losing their sight.
27PREVENTIONImprovement of diet so as to ensure a regular and adequate intake of food rich in vitamin AReducing respiratory tract infections, diarrhoea and measles.Both are long term measures involving intensive nutrition education of the public and community participation.Supply of fortified foods .Vitamin-A capsule iu months( children 6months years)