Iodine in human healthIodine in human health

Iodine Deficiency DisorderesIodine Deficiency Disorderes

● ● Iodine is a chemical element Iodine is a chemical element ( as are Oxygen ,Hydrogen , Iron ) ( as are Oxygen ,Hydrogen , Iron ) occurs in a variety of chemical formsoccurs in a variety of chemical forms

●● Iodine is an essential trace Iodine is an essential trace element for the humanelement for the human

●● Iodine is an essential Iodine is an essential part of the chemical part of the chemical structure of thyroid structure of thyroid hormoneshormones

Total quantity present in body is (15-20

mg)

Mostly in thyroid gland

DeficiencyDeficiency

According to the World Health Organization According to the World Health Organization (WHO), iodine deficiency disorders (IDD) (WHO), iodine deficiency disorders (IDD) affect 740 million people throughout the affect 740 million people throughout the world, and nearly 50 million people suffer world, and nearly 50 million people suffer from some degree of IDD-related brain from some degree of IDD-related brain damage damage

mental retardation, mental retardation, hypothyroidism, , goiter, , and varying degrees of other growth and and varying degrees of other growth and developmental abnormalities developmental abnormalities

Seawater contains 50 ppm (parts per Seawater contains 50 ppm (parts per million) iodine which means that there are million) iodine which means that there are approximately 76 billion pounds of iodine in approximately 76 billion pounds of iodine in the world’s oceans. the world’s oceans.

Seaweed was a major source of iodine Seaweed was a major source of iodine before 1959.before 1959.

Seaweed is a significant source for iodine in Seaweed is a significant source for iodine in the diets of many people around the world.the diets of many people around the world.

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Daily adult requirements, currently Daily adult requirements, currently recommended at 150 µg/day, could be recommended at 150 µg/day, could be covered by very small quantities of seaweed.covered by very small quantities of seaweed.

Just one gram of dried brown algae provides Just one gram of dried brown algae provides from 500-8,000 µg of iodine from 500-8,000 µg of iodine

Even the green and red algae (such as the Even the green and red algae (such as the purple nori that is used in Japanese cuisine) purple nori that is used in Japanese cuisine) provides 100-300 µg in a single gram.provides 100-300 µg in a single gram.

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Iodine absorptionIodine absorption

Oral.  Oral.  Iodine appears to be inactivated by Iodine appears to be inactivated by combination with gastrointestinal contents. combination with gastrointestinal contents. Absorption is poor due to rapid conversion of Absorption is poor due to rapid conversion of iodine to iodide.  (Reynolds, 1989; Gilman et al., iodine to iodide.  (Reynolds, 1989; Gilman et al., 1990).1990).

"Inhalation.  "Inhalation.  Iodine is absorbed from the lungs, Iodine is absorbed from the lungs, converted to iodide in the body, (ILO 1971). converted to iodide in the body, (ILO 1971). Pulmonary absorption of vapour may result in Pulmonary absorption of vapour may result in systemic poisoning (Gosselin et al., 1984).systemic poisoning (Gosselin et al., 1984).

  

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Absorption…….Absorption……."Dermal."Dermal. Only very small quantities of iodine are Only very small quantities of iodine are

absorbed through an  intact skin, (Reynolds, 1989). absorbed through an  intact skin, (Reynolds, 1989). Iodine can be absorbed by wounds and abrasions. Iodine can be absorbed by wounds and abrasions. Enhanced absorption occurs through denuded skin, Enhanced absorption occurs through denuded skin,

decubitus ulcers, mucosal surfaces with high decubitus ulcers, mucosal surfaces with high absorptive capacity , or large areas of intact skin, absorptive capacity , or large areas of intact skin, (Dela Cruz et al., 1987; Vorherr et al., 1989; Prager (Dela Cruz et al., 1987; Vorherr et al., 1989; Prager & Gardner 1979; Cosman et al., 1988).  & Gardner 1979; Cosman et al., 1988). 

"Eye.  "Eye.  Iodine can be absorbed when applied on the Iodine can be absorbed when applied on the eye, (Geisthoevel, 1984).eye, (Geisthoevel, 1984).  

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Iodine transportIodine transport

Active IActive I-- accumulation in the thyroid is mediated accumulation in the thyroid is mediated by the Naby the Na++/ I/ I-- symporter (NIS), a plasma symporter (NIS), a plasma membrane glycoprotein membrane glycoprotein

Using as its driving force the Na+ gradient Using as its driving force the Na+ gradient generated by the Nagenerated by the Na++_-K_-K++_-ATPase, NIS couples _-ATPase, NIS couples the inward movement of Nathe inward movement of Na++ in favor of its in favor of its concentration gradient to the inward movement concentration gradient to the inward movement of Iof I-- against its electrochemical gradient. against its electrochemical gradient.

Characteristic hallmarks of NIS are its Na Characteristic hallmarks of NIS are its Na dependencedependence

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NIS mediates I uptake in several tissues NIS mediates I uptake in several tissues besides the thyroid, including :besides the thyroid, including :

Lactating mammary gland, Lactating mammary gland, Gastric mucosa,Gastric mucosa, & salivary glands& salivary glands It appears that NaIt appears that Na++/ I/ I-- symporter is symporter is

present in GI tract small intestine)present in GI tract small intestine)

  

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Pyramidal lobe

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Thyroid Hormones Contain 3-4 Thyroid Hormones Contain 3-4 Atoms of IodineAtoms of Iodine

Role of IodineRole of Iodine IodineIodine is needed for the synthesis of thyroid is needed for the synthesis of thyroid

hormones. hormones. Thyroid hormone:Thyroid hormone:

MetabolicThermogenicCarbohydrate metabolismProtein metabolismFat metabolism

Effect on organsCardiovascular systemRespiratory systemCentral system

Plays a key role in cell replicationEspecially relevant for the brain

Neural cells multiply mainly in utero and during the first 2 years of life

Fetal deficiency leads toIncreased rates of spontaneous abortionStillbirthsCongenital anomaliesCretinismPsychomotor deficitsNeonatal mortality

The spectrum of IDDThe spectrum of IDDFetus Abortions

StillbirthsCongenital anomaliesIncreased perinatal mortalityNeurologic creatinismPsychomotor defects

Neonate Neonatal goiterNeonatal hypothyroidims

Child & adolescent Goitrous juvenile hypothyroidism Impaired mental function Retarded physical development

Adult Goiter with its complications HypothyroidismImpaired mental function 1616

IDD and selenium deficiencyIDD and selenium deficiency

Se part of peripheral type I de-Iodinase (kidney Se part of peripheral type I de-Iodinase (kidney and liver) and liver)

Se deficiency: slower T4 to T3 metabolisationSe deficiency: slower T4 to T3 metabolisation Se part of Glutathion peroxidase : protector of Se part of Glutathion peroxidase : protector of

HH22OO22 damage Thyroid damage, disfunction of damage Thyroid damage, disfunction of thyroidthyroid

Cerebral de-iodinase is not Se dependent Cerebral de-iodinase is not Se dependent Glutathion peroxidase stimulates T4 productionGlutathion peroxidase stimulates T4 production

The Recommended Dietary The Recommended Dietary Allowance (RDA)Allowance (RDA)

Recommended Dietary Allowance (RDA) for IodineRecommended Dietary Allowance (RDA) for Iodine

Life Stage Life Stage  Age Age  Males Males (mcg/day) (mcg/day) 

Females Females (mcg/day) (mcg/day) 

Infants Infants  0-6 months0-6 months 110 (110 (AI)) 110 (110 (AI))

Infants Infants  7-12 months 7-12 months    130 (AI) 130 (AI)    130 (AI) 130 (AI) 

Children Children  1-3 years 1-3 years  90 90  90 90 

ChildrenChildren   4-8 years 4-8 years  90 90  90 90 

Children Children  9-13 years 9-13 years  120 120  120 120 

Adolescents Adolescents  14-18 years 14-18 years  150 150  150 150 

Adults Adults  19 years and 19 years and olderolder 150 150  150 150 

Pregnancy Pregnancy  all ages all ages  - -  220220

Breastfeeding Breastfeeding  all ages all ages  - -  290290 

Food sourcesFood sources FoodFood ServingServing Iodine (mcg)Iodine (mcg)

Salt (iodized)Salt (iodized) 1 gram1 gram 7777

CodCod 3 ounces3 ounces 9999

ShrimpShrimp 3 ounces3 ounces 3535

Fish sticksFish sticks 2 fish sticks2 fish sticks 3535

Tuna, canned in oilTuna, canned in oil 3 ounces (1/2 can)3 ounces (1/2 can) 1717

Milk (cow's)Milk (cow's) 1 cup (8 fluid ounces)1 cup (8 fluid ounces) 5656

Egg, boiledEgg, boiled 1 large1 large 2929

Navy beans, cookedNavy beans, cooked 1/2 cup1/2 cup 3535

Potato with peel, bakedPotato with peel, baked 1 medium1 medium 6363

Turkey breast, bakedTurkey breast, baked 3 ounces3 ounces 3434

SeaweedSeaweed 1 ounce, dried1 ounce, dried Variable; may be Variable; may be greater than 18,000 greater than 18,000

mcg (18 mg)mcg (18 mg)

GoiterGoiter

Endemic goiterEndemic goiter

More than 5% of More than 5% of

the preadolescent the preadolescent

(6-12 years) school (6-12 years) school

age children have age children have

enlarged thyroid glands. enlarged thyroid glands.

2121Simple (nontoxic goiter)

Endemic CretinismEndemic Cretinism(Neurologic Form)(Neurologic Form)

Sever mental deficiencySever mental deficiency Deaf mutism (Cochlear lesion)Deaf mutism (Cochlear lesion) Motor spasticity (spastic diplegia)Motor spasticity (spastic diplegia)

proximal rigidity of both lowerproximal rigidity of both lower

and upper extremities and the trunk. and upper extremities and the trunk. GoiterGoiter

2222

23

Endemic CretinismEndemic Cretinism(Neurologic Form)(Neurologic Form)

Endemic CretinismEndemic Cretinism(Myxedematous Form)(Myxedematous Form)

2424

Less sever degree of mental Less sever degree of mental

retardation retardation Sever growth retardationSever growth retardation Puffy featuresPuffy features Myxedematous and dry skinMyxedematous and dry skin Delayed sexual maturation Delayed sexual maturation No goiterNo goiter

25

An adult male from the Congo,

with three women of the same

age (17-20 years),

all of whom are myxedematous cretins.

Myxedematous Cretinism

Individuals at risk of iodine Individuals at risk of iodine deficiencydeficiency

Vegetarian and nonvegetarian diets that Vegetarian and nonvegetarian diets that exclude iodized salt, fish, and seaweed exclude iodized salt, fish, and seaweed have been found to contain very little iodine have been found to contain very little iodine

GoitrogensGoitrogens

Some foods contain substances that interfere with iodine Some foods contain substances that interfere with iodine utilization or thyroid hormone production utilization or thyroid hormone production

Some species of millet and cruciferous vegetables (for Some species of millet and cruciferous vegetables (for example, cabbage, broccoli, cauliflower, and Brussel example, cabbage, broccoli, cauliflower, and Brussel sprouts) sprouts)

The soybean isoflavones, genistein and daidzein, have The soybean isoflavones, genistein and daidzein, have also been found to inhibit thyroid hormone synthesis also been found to inhibit thyroid hormone synthesis

Most of these goitrogens are not of clinical importance Most of these goitrogens are not of clinical importance unless they are consumed in large amounts or there is unless they are consumed in large amounts or there is coexisting iodine deficiency coexisting iodine deficiency

GoitrogensGoitrogens are inactived in heat are inactived in heat

Acute toxicityAcute toxicity&&Iodine excessIodine excess

Tolerable Upper Intake Level (UL) for Iodine Tolerable Upper Intake Level (UL) for Iodine

Age Group  Age Group   UL (mg/day)UL (mg/day)

Infants 0-12 monthsInfants 0-12 months Not possible to establish*Not possible to establish*

Children 1-3 yearsChildren 1-3 years 200 mcg/day200 mcg/day

Children 4-8 years  Children 4-8 years   300 mcg/day300 mcg/day

Children 9-13 years  Children 9-13 years   600 mcg/day600 mcg/day

Adolescents 14-18 yearsAdolescents 14-18 years 900 mcg/day900 mcg/day

Adults 19 years and olderAdults 19 years and older 1,100 mcg/day (1.1 mg/day)1,100 mcg/day (1.1 mg/day)

*Source of intake should be from food and formula only.

Prevention Prevention

PreventionPrevention

Use of iodine solution(oral or injectional):Use of iodine solution(oral or injectional):

- In population that incidence is >70%In population that incidence is >70%

- If iodide salt is not availableIf iodide salt is not available

- One IM injectionOne IM injection 0/5-1ml is sufficient for 3-0/5-1ml is sufficient for 3-5 years5 years

- One oral dose is sufficient for 1-2 yearsOne oral dose is sufficient for 1-2 years

Summary of IDD Control Status in Summary of IDD Control Status in EMROEMRO

Source: Elimination of Iodine Deficiency Disorders, a manual for Health Workers: WHO, 2006

Recent Scenarios on IDDRecent Scenarios on IDD

There are fewer countries (47) where IDD is There are fewer countries (47) where IDD is considered to be a public health problem in recent considered to be a public health problem in recent years. years.

Conversely, there is a substantial number of Conversely, there is a substantial number of countries (34) where the level of Iodine intake is countries (34) where the level of Iodine intake is too high exposing susceptible groups to the risk of too high exposing susceptible groups to the risk of Iodine-induced hyper-thyroidism.Iodine-induced hyper-thyroidism.

Urinary IodineUrinary Iodine

Reflects directly intakeReflects directly intake Is best to follow up programme response, Is best to follow up programme response,

goitre takes time to decrease in sizegoitre takes time to decrease in size Samples needed are smallerSamples needed are smaller Technique is simple and not expensiveTechnique is simple and not expensive Samples can be taken easily, cheap, Samples can be taken easily, cheap,

acceptable and don’t need conservation acceptable and don’t need conservation techniquestechniques

Table 5. Epidemiological criteria for assessing iodine nutrition based on median urinary iodine concentrations in school-aged children Median urinary iodine

Iodine intake (µg/L)

Iodine nutrition

< 20 Insufficient Severe iodine deficiency 20-49 Insufficient Moderate iodine deficiency 50-99 Insufficient Mild iodine deficiency 100-199 Adequate Optimal 200-299 More than adequate Risk of iodine-induced

hyperthyroidism within 5-10 years following introduction of iodized salt in susceptible

> 300 Excessive Risk of adverse health consequences (iodine-induced hyperthyroidism, autoimmune thyroid diseases)

From WHO/UNICEF/ICCIDD (2)

يد اختالالت كنترل يد در اختالالت كنترل WHO WHO درمعيارهايمعيارهاي

از- 11 بيش درخانوار يددار نمك از- مصرف بيش درخانوار يددار نمك درصد درصد 9090مصرف

از- 22 كمتر ادرار از- يد كمتر ادرار از ug/dlug/dl 1010يد از كمتر درصد درصد 5050كمتر از كمتر ادرار از يد كمتر ادرار از ug/dlug/dl 55يد از كمتر درصد درصد 2020كمتر

كودكان- 33 تيروئيد كودكان- اندازه تيروئيد از 66--1212اندازه كمتر از ساله كمتر 55سالهدرصددرصد

44 - -TSHTSH از بيشتر از نوزادان بيشتر /55نوزادان واحد /ميلي واحد از LLميلي از كمتر درصد درصد 33كمتر

راهکارها راهکارها يددار نمک توليدوتوزيع کيفيت يددار کنترل نمک توليدوتوزيع کيفيت کنترل وبازآموزي همگاني هاي وبازآموزي آموزش همگاني هاي آموزش يدادرارکودکان ميزان گيري يدادرارکودکان اندازه ميزان گيري براي 88--1010اندازه براي ساله ساله

ساله يک درمقاطع يدکافي ازدريافت ساله اطمينان يک درمقاطع يدکافي ازدريافت اطمينان برنامه وکمي روندکيفي برنامه پايش وکمي روندکيفي پايشارزشيابي برنامهارزشيابي برنامه

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