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NUTRITION-V. Dr M.Rashid Anjum Community Medicine Department Army Medical College. VITAMINS (Micronutrients). QUESTIONS? 1.What are vitamins? 2.Why these are essential for body? 3.What happens if there is deficiency of vitamins?. VITAMINS. Organic Compounds (C-containing)
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NUTRITION-V Dr M.Rashid Anjum Community Medicine Department Army Medical College
VITAMINS(Micronutrients) QUESTIONS? 1.What are vitamins? 2.Why these are essential for body? 3.What happens if there is deficiency of vitamins?
VITAMINS • Organic Compounds (C-containing) • Essential for Growth Body functions Maintenance
VITAMINS:TWO-GROUPS • FAT SOLUBLE WATER SOLUBLE • Vit-A 8 B-VITAMINS & VIT-C • Vit-D B-1 Thiamin • Vit-K B-2 Riboflavin • Vit-E B-3 Niacin B-6 Pyridoxine B-12 Cyanocobalamin Pantothenic acid Biotin Folate
PROVITAMINS “An inactive form of a vitamin that the body can convert into an active use-able form. Example: Carotenoid Precursor of Vit A in foods of plant origin.Present in many fruits and vegetables.
Major Role of Vitamins: AntioxidantsCoenzymes Vit E 8 B-Vitamins Vit C Vision Carotenoids Vit A Bone Health Blood Clotting Vit D Vit K Vit K
VITAMIN-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)
Vitamin A interconversions Retinal Retinoic acid Retinol
STORAGE &TRANSPORT Liver 90 % Adipose tissues Lungs & kidneys 10% (stored as retinyl esters) Transported by retinol binding protein (RBP) Serum range of RBP = 40-50 mcg/dL.
SOURCES OF VITAMIN-A • Animal food 50% (as preformed Vit-A) Cod liver oil, Milk fat, Meat, Eggs ,Fortified foods like Margarine. • Fruits and Vegetables 50% (as provitamin-A , carotenoids) Carrots,Spinach,Broccoli,Potatoes, Apricot,Mangoo.Papaya,Pumpkin
MEASURING UNIT RAE (Retinol Activity Equivalent) 1 RAE = 1 microgram Retinol = 12 microgram beta carotene = 24 microgram carotenoids
RECOMMENDED DAILY ALLOWANCE MALE 900 microgram RAE FEMALE 700 microgram RAE PREGNANT WOMEN 770 microgram RAE LACTATING WOMEN 1300 microgram RAE INFANTS 400 microgram RAE
FUNCTIONS 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)
VITMIN-A DEFICIENCY EYE: The signs of vitamin A deficiency are predominantly ocular • Nightblindness • Conjunctival xerosis • Bitot’s spots • Corneal xerosis • Keratomalacia XEROPHTHALMIA: (dry eyes) includes all ocular manifestations ranging from night blindness to keratomalacia.
VITMIN-A DEFICIENCY • NIGHTBLINDNESS Lack of vitamin A first causes night blindness or inability to see in dim light. • CONJUNCTIVAL XEROSIS This is the first clinical sign of vitamin A deficiency. The conjunctiva becomes dry and non-wettable.
VITAMIN- 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.
VITAMIN-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.
VITAMIN-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.
EXTRA-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.
TREATMENT • All 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.
EPIDEMIOLOGY • An estimated 250 million preschool children and 19 million pregnant women are vitamin A deficient globally. • An estimated 250 000 to 500 000 vitamin A deficient children become blind every year, half of them dying within 12 months of losing their sight.
PREVENTION • Improvement of diet so as to ensure a regular and adequate intake of food rich in vitamin A • Reducing 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 200000 iu 4-----6 months ( children 6months-------6 years)