Vit a and vit a deficiency disorders

Vitamin A and its importance as well as its deficiency manifestations

1. Vitamin A and Vitamin A Deficiency D isorders Dr. Moumita Pal MBBS,DPH, MD Dept. of Community Medicine College of Medicine and Sagore Dutta Hospital

2. Vitamin A Active form-Retinol Proactive form (precursor)- Carotinoids Fat soluble Stable to heat at ordinary cooking temperature. IU of Vit.A =0.3 mcg of Retinol RE: Retinol equivalent ( Vit A activity) 1mcg of retinol=1 RE=3.33IU Vit A 2

3. Functions Formation of rhodopsin in Rods of retina. Helps in dark adaptation Integrity of cellular structures specially epithelial tissue ( respiratory, GI tract, GU tract, skin) Role in immune defense mechanism Antioxidant property of free radical scavenging Skeletal growth Protects against certain cancers like bronchial cancers 3

4. Sources 1. Animal Foods (retinol) : Liver, meat, kidney, milk, fish, eggs. Richest source is fish liver oil. 4

5. Sources 2. Plant foods ( carotenoids ): coloured fruits and vegetables. - green leafy vegetables ( spinach, amaranth) -yellow orange vegetable and fruits( pumpkin, mango, papaya, apricots, carrots) Carotene converted to Vit A in small intestine. Pigments with no vit A activity: Lycopene in tomatoes 5

6. Vit E protects it from oxidation Destroyed by exposure to sunlight Heating for a long time Drying and dehydration 3. Fortified foods: vanaspati margarine, milk 6

7. Storage Liver Retinol palmitate mostly Well fed person has sufficient reserve for 6-9 months Retinol ( free) highly toxic. Transported in blood with retinol binding protein ( produced in liver) 7

8. Requirements and recommendations Groups Retinol RDA (mcg) Adults ( Male/female) Children >6 years Adolescents 600 Children (1-6 years) 400 Infants (<12 months) 350 Pregnancy 800 Lactation 950 8

9. Toxicity Induced by single dose of >200mg ( 200000RE) Chronic - >4000 RE (infants) to 7000 RE (adults) consumed daily Persistent large dose > 100 times of required dose daily overwhelm liver storage capacity and produced intoxication Skin/mucous membrane changes Dry lips, dryness of nasal mucosa and eyes, erythema , scaling, peeling of skin, hair loss and nail fragility Headache, nausea vomiting Toxic to fetus (teratogenic): craniofacial, CNS, cardiovascular, thymic malformation 9

10. Deficiency 10

11. Signs and symptoms Dryness, itching and redness of conjunctiva Night blindness ( inability to see in dim light) Others signs of xerophthalmia : Bitot spots, corneal xerosis , keratomalasia Dry rough itchy skin: rash Dry brittle hair and nail Loss of acuity of senses : smell and taste Loss of appetite Fatigue Poor growth Low immunity/ vulnerability to infections Increased risk of certain cancers 11

12. Vitamin A deficiency Leading cause of preventable blindness in children Major cause of controllable public health and nutrition problem in India 5.7 % children of India suffer from s/s Only 21 % children (12-35months age) received Vit A supplementation Less than 10% coverage in Nagaland & UP 12

13. Etiological factors Most common in 1-3 years age group Weaning and infections: Mothers not conversant with correct weaning practices Low vit A diet: diluted milk, poor starchy food, no fruits, butter, vegetables or animal food Ignorance and economic reasons Repeated infection during teething, weaning, exposure to the outer world  high demand PEM  immunologically vulnerable High rate of diarrhoea, respiratory infections measles compromised Vit A status 13

14. Social factors Cultural belief on BF and weaning Discarding colostrum, early or late weaning, restrictions of food items, excessive dilution of milk, vegetarianism, unscientific management of infection, belief in quacks Poverty 14

15. Poor environmental sanitation Practices: Non availability of sanitary latrines Open air defecation Poor hygienic practices Lack of potable water 15

16. Other causes Vegetarians Prolonged dietary deprivation Chronic alcoholics Sprue Duodenal bypass Chronic diarrhea Cirrhosis 16

17. Xerophthalmia DEFINITION: “an abnormal dryness of the eyeball produced usually by Long-continued inflammation and subsequent atrophy of the Conjunctiva and cornea.” Ocular manifestation of Vit A deficiency in various clinical forms Leads to blindness but preventable 17

18. Xerophthalmia as a public health problem WHO classification Clinical condition Prevalence among pre school children XN Night blindness >1% X1A Conjunctival xerosis - X1B Bitot’s spot >0.5% X2 Corneal xerosis - X3A Corneal ulceration/ Keratomalacia (involving <1/3 of cornea) >0.01% X3B Corneal ulceration/ Keratomalacia (involving >1/3 of cornea) >0.01% XS Corneal scar >0.05% XF Xerophthalmic fundus - Bio chemical Plasma retinol <0.35 micro mol/L >5% 18

19. Night blindness First symptom Inability to see in dim light Due to impaired dark adaptation Can be diagnosed by mother when- in the evening child strikes against a stone and while play and fall down/ unable to see the content of food plate and gropes for food/ in a dimly lit classroom can’t see blackboard Reversible with Vit A 19

20. Conjunctival Xerosis First clinical sign Cornea and tissue of the eye become dry , wrinkled (vertically folded) and thickened Restricted to “exposed” bulbar conjunctive Dryness looks like waxy paint as lose of transparency and shiny appearance loss of goblet cells /Less mucin production  Un wettable cornea 20

21. Bitot’s Spot Triangular pearly white/yellowish foamy spots on bulbar conjunctiva Either side of cornea Due to hyper-keratinizing metaplasia of epithelium & accumulations of seborrhoeic excretions. Diagnostic in children but adult- inactive sequelae of earlier disease. 21

22. Corneal xerosis Cornea appears dry dull and non wettable Serious condition May progress to corneal ulceration Ulcer may heal leaving a scar behind Affect vision 22

23. Keratomalacia Liquefaction of cornea Grave medical emergency-process is rapid Cornea becomes soft and burst open Through this content of eye may extrude out Eye collapses & vision lost 23

24. Extra ocular manifestations Follicular hyperkeratosis Growth retardation Anorexia Non specific & difficult to quantify 24

25. Treatment schedule for xerophthalmia for all age groups except women of reproductive age Timing Vit A dosage Immediately on diagnosis (day 1) -<6 months of age -6-12 months ->12 months -50000 IU -100000IU -200000IU (110 mg) Next day ( day 2) Same age specific dose At least 2 weeks later Same age specific dose Vit A in oil/ Retinol Palmitate http://apps.who.int/iris/bitstream/10665/41947/1/9241545062.pdf 25

26. Women of reproductive age Daily oral dose of 5000-10000IU for 4 weeks Such daily dose should never exceed 10000IU 26

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28. XEROPHATHALMIA FUNDUS: Pale yellow spots near the course of the retinal vessels and in the retinal periphery Disappear with 2- 4 months of vitamin A therapy 28

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30. Prevention Dietary modification Vit A or beta carotene rich food Nutrition education Importance of vitamin rich diet, regular intake, harmful effects of deficiency Fresh seasonal fruits and vegetables Healthy food preservation techniques Public meeting, schools and Mass media may be used 30

31. Fortification Ghee, dalda , butter, margarine, dried skimmed milk etc. Periodic massive dosage NIS First dose- 100000 IU at 9 th completed months along with measles vaccine Then 200000IU at 16 months with DPT/OPV booster. Then same dose at 6 months interval up-to 5 years Total 9 mega-doses 31

32. Long term actions Continuous nutritional education Importance of immunization Environmental sanitation Breast feeding Early treatment of infection Good maternal and child health care 32

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