Micronutrient malnutrition II

1. Micronutrient malnutrition II Vanessa Velazquez-Ruiz, MD Emergency Medicine Global Health Fellow St. Luke’s-Roosevelt Hospital

2. Today schedule…. • Zinc Deficiency • Iodine deficiency

3. Are you ready!!!!!! Lets begin the second part of our journey

5. Zinc Deficiency • Common but overlooked problem in developing countries • Important role in biological processes • Gene expression • Cell development • Replication • Immune function • Growth and development

6. Overview Intakes of zinc are commonly lower than recommended Adaptation mechanisms preclude the development of severe deficiencies Many consequences to adaptation states to low zinc levels

7. Overview Probably affects a quarter or a third of pre school children and their mothers Lack of simple quantitative markers for zinc deficiency Overall, 20.5% of the world population is at risk of zinc deficiency Estimated to be responsible for 800,000 deaths/year from diarrhea, malaria, pneumonia in children under five

8. Zn deficiency in world crops: major areas of reported problems (adapted from Alloway, 2008a One of the ten largest contributors to the burden of disease in developing countries

9. Overview • Incidence and prevalence have not been defined • Lack of sensitive, practical, accepted indicators for zinc deficiency • Population-based surveys have not been done • Marginal deficiency is not characterized as a specific syndrome • Severe clinical deficiency is not seen owing to adaptation or death

10. Risk factors for zinc deficiency • Insufficient dietary intake (low protein diet) • High phytate and/or fiber intake (vegetarians) • Diarrheal disease • Malabsorption syndromes • Parasitosis • Hot, humid climate • Lactation • Rapid multiplicative cell growth (pregnancy, infancy, adolescence) • Genetic disease (acrodermatitis enteropatthica, Sickel cell anemia)

11. Close geographical linkage between soil zinc deficiency and human zinc deficiency

12. Zinc Metabolism

13. Zinc absorption Absorbed at all levels of the small intestine Intestine must recover zinc from both diet and endogenous sources Total body zinc content maintained with absorption of 5mg/day

14. Zinc Storage • No specific organ for storage • 60% striated muscle • 20% in bone • 5% in blood and liver • 3% in the skin and GI tract

15. Zinc excretion Mostly in feces Through urine In tropical countries, sweat losses can be considerable Turnover of skin, hair and nails Menstrual blood and semen Lactation (2-3mg per day in the first several weeks)

16. Sources of zinc • Animal products, seafood, cereals • Oysters and shellfish • Absorption impaired by phytates and fiber. • Protein acts as anti-phytate

17. Clinical presentation • Severe deficiency • Growth retardation • Impaired immune system • Skin lesions in extremities and perioral area • Hypogonadism • Anorexia • Cognitive dysfunction • Alopecia

18. Mild to moderate • Increases susceptibility to infection • Growth retardation • Failure to thrive • Impaired taste (hypogeusia)

19. During pregnancy • Birth defects • Spontaneous abortions • Fetal growth retardation • Low birth weight • Preterm delivery • Increase complications during delivery

20. Impairs estrogen-dependent gene expression in the uterus (via zinc-finger protein) Lack of estrogen impairs the conversion of uterus from passive state to one capable of concerted contractions with sufficient force to expel fetus

21. Zinc and diarrheal disease Strong evidence that supplements improves the prognosis (reduces severity and duration) of children treated for diarrheal disease Zinc supplement + oral rehydration treatments been explored UNICEF recommends packs of ten tablets of 20mg Zinc/daily for tx of diarrhea

22. Zinc and respiratory diseases Regular zinc supplements have shown to prevent respiratory diseases in children with lower birth weights Pool analysis of randomized controlled trails showed reduction of pneumonia by 41% in preschool children supplemented with zinc One trial in Bangladesh showed reduced duration of severe pneumonia by 30% with zinc as adjunct therapy

23. Zinc and malaria Gambia: 32% fewer clinic visits for malaria due to Plasmodium falciparum in young children supplemented with Zinc 69% reduction for malaria episodes accompanied by high levels of parasitemia (>10,0000 parasites/μL)

24. Zinc and HIV Low serum Zinc identifies in 29% of hospitalized AIDS patients Some studies showed that low zinc levels may reflect HIV replication and the possibility that Zinc may enhance viral replication, however, Daily zinc supplementation for 30 days has proven to reduce infectious disease morbidity in AIDS patients in other studies

25. http://www.zincsaveskids.org/ http://www.youtube.com/watch?v=vN_qQPxPK3Q

26. Assessment • Plasma and Serum Zinc concentration • Circulating zinc less than 0.2% of total body • Cut-off values to assess risk of zinc deficiency • Below 10.71 μmol/L for fasting sample and less then 9.95μmol/L for non fasting

27. Dietary assessment • Food intake distributions of a population • Analysis of local staple foods • Recall of an individual for food consumed • Weighed food records by research assistants • 24-hr dietary recall • Local food composition tables if available

28. Other • Hair zinc concentrations • Diminished taste acuity (hypogeusia) • Composite index for predicting the national risk of zinc deficiency- uses a combination of stunting rates and adequacy of zinc in the national supple

29. Replacement and treatment

30. Table 1: Recommended Dietary Allowances (RDAs) for Zinc Age Male Female Pregnancy Lactation 0–6 months 2 mg* 2 mg*     7–12 months 3 mg 3 mg     1–3 years 3 mg 3 mg     4–8 years 5 mg 5 mg     9–13 years 8 mg 8 mg     14–18 years 11 mg 9 mg 12 mg 13 mg 19+ years 11 mg 8 mg 11 mg 12 mg * Adequate Intake (AI)

31. Recommended nutrient intakes (RNIs) for dietary zinc (mg/day) to meet the normative storage requirements from diets differing in zinc bio-availability

32. Treatment • To combat zinc deficiency, five intervention strategies can be used: • Supplementation using medicines • Food fortification through the incorporation of zinc additives in food • Dietary modification/diversification • Genetic biofortification through plant breeding • Agronomic biofortification through zinc fertilization.

35. Iodine deficiency

36. Overview Iodine is an essential constituent of the thyroid hormones (T4, T3) Deficiency can lead to Goiter or cretinism depending on the severity The ongoing global health effort to eliminate iodine deficiency through iodization of salt presents one of the largest public health efforts

37. By 1990, there were 1,572 million people worldwide consuming inadequate amounts of iodine Iodine deficiency is the leading cause of mental retardation in the world Problem is global, with mountainous regions and large river deltas the most well-known areas of endemic deficiencies

38. Epidemiology Mountainous areas, high altitude and alluvial plains

39. Leaching of iodine form the soil due to erosion and heavy rain, deforestation, overgrazing lead to loss of iodine form soil and water

40. WHO Region Proportion of population with UI Population with < 100 µg/L (%) UI < 100 µg/L (millions) Africa 42.6 260.3 Americas 9.8 75.1 South East Asia 39.8 624 Europe 56.9 435.5 Eastern Mediterranean 54.1 228.5 Western Pacific 24 365.3 Total 35.2 1988.7 192 WHO Members States 
Based on population estimates for the year 2002 (United Nations, Population Division, World Population Prospects: The 2002 Revision)

41. WHO 2003

42. Risk factors • Residency in an area where soil and water are poor in iodine • Ingestion of substances known as “goitrogens”( found in vegetables and fiber) that can interfere with metabolism • Cabbage, sweet potato, brussel sprouts, turnips • Cassava containing high concentration of thiocyanates

43. Role of iodine in biological functions • Metabolism • Growth and development • Synthesis of growth hormone • Normal bone cell growth and development • Brain development • Early growth and differentiation of the brain and nervous systems in the fetus • Immune function

45. Sources of Iodine Seafood and seaweed Crops grown on iodine rich soil Iodized salt Drinking water (less than 10%)

46. WHO recommended dietary requirements

47. Spectrum of iodine deficiency disorders • Fetus • Abortions • Stillbirths • Congenital anomalies • Increase perinatal mortality • Neurological cretinism: mental deficiency, deaf-mutism, spastic diplegia, squint • Myxoedematous cretinism: dwarfism, mental deficiency

48. Spectrum of iodine deficiency disorders • Neonate • Neonatal goiter • Neonatal hypothyroidism

49. Spectrum of iodine deficiency disorders • Child and adolescent • Goiter • Juvenile hypothyroidism • Retarded physical development

50. Spectrum of iodine deficiency disorders • Adult • Goiter • Hypothyroidism • Impaired mental function • Iodine-induce hyperthyroidism