Transcript Micronutrient deficiencies II

Micronutrient
malnutrition II
Vanessa Velazquez-Ruiz, MD
Emergency Medicine
Global Health Fellow
St. Luke’s-Roosevelt Hospital
Today schedule….
 Zinc Deficiency
 Iodine deficiency
Lets begin the second part of our journey
Are you ready!!!!!!
Zinc Deficiency
 Common but overlooked problem in developing
countries
 Important role in biological processes
 Gene expression
 Cell development
 Replication
 Immune function
 Growth and development
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
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
 One of the ten largest contributors to the burden of
disease in developing countries
Zn deficiency in world crops: major areas of reported problems (adapted
from Alloway, 2008a
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
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)
Close geographical linkage between soil zinc deficiency and
human zinc deficiency
Zinc Metabolism
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
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
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)
Sources of zinc
 Animal products, seafood, cereals

Oysters and shellfish
 Absorption impaired by phytates and fiber.

Protein acts as anti-phytate
Clinical presentation
 Severe deficiency
 Growth retardation
 Impaired immune system
 Skin lesions in extremities and perioral area
 Hypogonadism
 Anorexia
 Cognitive dysfunction
 Alopecia
 Mild to moderate
 Increases susceptibility to infection
 Growth retardation
 Failure to thrive
 Impaired taste (hypogeusia)
 During pregnancy
 Birth defects
 Spontaneous abortions
 Fetal growth retardation
 Low birth weight
 Preterm delivery
 Increase complications during delivery
 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
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
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
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)
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
 http://www.zincsaveskids.org/
 http://www.youtube.com/watch?v=vN_qQPxPK3Q
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
 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
 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
Replacement and
treatment
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)
Recommended nutrient intakes (RNIs) for dietary zinc (mg/day) to meet the
normative storage requirements from diets differing in zinc bio-availability
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.
Iodine deficiency
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
 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
Epidemiology
 Mountainous areas, high altitude and alluvial plains
 Leaching of iodine form the soil due to erosion and
heavy rain, deforestation, overgrazing lead to loss of
iodine form soil and water
WHO Region
Proportion of population with UI
< 100 µg/L (%)
Africa
42.6
Americas
9.8
South East Asia
39.8
Europe
56.9
Eastern Mediterranean 54.1
Western Pacific
24
Total
35.2
Population with
UI < 100 µg/L
(millions)
260.3
75.1
624
435.5
228.5
365.3
1988.7
192 WHO Members States Based on population estimates for the year 2002 (United
Nations, Population Division, World Population Prospects: The 2002 Revision)
WHO 2003
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
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
Sources of Iodine
 Seafood and seaweed
 Crops grown on iodine rich soil
 Iodized salt
 Drinking water (less than 10%)
WHO recommended dietary
requirements
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
Spectrum of iodine deficiency
disorders
 Neonate
 Neonatal goiter
 Neonatal hypothyroidism
Spectrum of iodine deficiency
disorders
 Child and adolescent
 Goiter
 Juvenile hypothyroidism
 Retarded physical development
Spectrum of iodine deficiency
disorders
 Adult
 Goiter
 Hypothyroidism
 Impaired mental function
 Iodine-induce hyperthyroidism
Goiter
 Enlargement of thyroid gland in response to insufficient
iodine intake
 Low iodine -> decrease T4 -> increase production of
TSH -> stimulates hyperplasia of the thyroid -> increase
uptake of iodine -> Goiter
 Definition by palpation: enlargement of the thyroid such
that lateral lobes are larger than the terminal phalanx of
the thumb of the person who is being examined
Goiter
 Severity of goiter correlates with severity of the
deficiency
 In areas of endemic goiter , the daily intake is less the
100 μg/day
Cretinism
 Usually found where the prevalence of endemic goiter is
more than 30%
 Characterized by mental retardation
 Two extreme types of cretinism:
 Neurological
 Myxoedematouse
 Myxoedematous cretinism (hypothyroid cretinism):
severe growth retardation, mental retardation not severe,
coarse, dry skin, husky voice.
 Neurological cretinism: stature is normal, mental
retardation is severe, deaf-mutism, cerebral diplegia
Assessment of iodine
status
 Urinary iodine
 Most useful/reliable indicator I status
 24hr or random (30 samples) urine collection
 Related to recent dietary I intake
Adequate
100-200 μg/L
Mild deficiency
50-99μg/L
Moderate Deficiency
20-49μg/L
Severe Deficiency
Less than 20μ/L
Assessment of iodine
status
 Thyroid size (goiter surveys)
 Palpation
 Ultrasound (more reliable)
 “Total Goiter Rate”, schoolchildren
Classification for Goiter
Grade 0
No palpable or visible goiter
Grade 1
Palpable mass but not visible when neck in
normal position
Grade 2
Visible, palpable swelling of the neck
Goiter by palpation or by thyroid volume by US (>97% of percentile)
Mild
5-19.9
Moderate
20-30
Severe
>30
*School-children
 TSH screening programs
 For early detection of congenital hypothyroidism
 Useful epidemiology information, not cost effective
 The degree of iodine deficiency can be evaluated on the basis of
the frequency of neonatal blood TSH above the cutoff point of
3μU/ml
Mild deficiency
TSH 3-19.9
Moderate deficiency
TSH 20-40
Severe deficiency
TSH > 40
Prevention
 Iodized salt: “Universal salt iodization” (150μg of I/day)
 Oral iodide oil
 Adult : 1ml (480mg)
 0.5ml (240mg)
 Iodized oil injections
Prevention
 Other:
 Iodization of drinking and irrigation water
 Iodine saturated silicon matrices placed in wells and hand
pumps
 Fortification of food
Conclusion
 Iodine deficiency is the leading cause of preventable mental
retardation
 Great progress in providing access to iodized salt
 WHO/UNICEF/ICCIDD report in 1999, from 5 billion
people living in counties with iodine deficiencies, 68% now
have access to iodized salt.
 From 130 counties, 104 have intersectoral coordination and
98 have legislations about iodized salt
 Much work needs to be done…
To be Continued…
Stay tune for more on micronutrient deficiencies next
week… same channel, same time
Thanks
Any questions…
References
WHO website