IRON DEFICIENCY & IDAIRON DEFICIENCY & IDA

Abdelaziz ElaminMD, PhD, FRCPCHProfessor of Child HealthCollege of MedicineSultan Qaboos UniversityMuscat, Omanazizmin@hotmail.com

HIDDEN HUNGERHIDDEN HUNGER

The term was coined by WHO in 1986 & refers to the problems associated with the deficiency of 3 essential micronutrients:IronIodine Vitamin A

LEARNING OBJECTIVESLEARNING OBJECTIVES

At the end of the lecture you will be able to: Discuss iron absorption, transport & stores Know the burden of IDA in the world Identify the causes & consequences of IDA Know how to diagnose IDA Recognize the strategies for control &

prevention of IDA

IRON IN NATUREIRON IN NATURE

Iron is among the abundant minerals on earth. Of the 87 elements in the earth’s crust, Iron

constitutes 5.6% and ranks fourth behind Oxygen (46.4%), Silicon (28.4%) and Aluminum (8.3%).

In soil, Iron is 100 times more than Ca, Na & Mg and1000 times more than Zinc and 100,000 times more than Iodine.

IRON DEFICIENCYIRON DEFICIENCY

Iron deficiency is the most common micronutrient deficiency in the world affecting 1.3 billion people i.e. 24% of the world population.

In comparison only 275 million are iodine deficient and 45 million children below age 5 years are Vitamin A deficient.

IRON DEFICIENCY /2IRON DEFICIENCY /2

Iron deficiency can range from sub-clinical state to severe iron deficiency anemia.

Different stages are identified by clinical findings & lab tests.

Anemia is defined as a hemoglobin below the 5th percentile of healthy population.

Most studies showed this cutoff point to be around 11 g/dl (-2SD below the mean).

HB IN IDAHB IN IDA

AT RISK GROUPSAT RISK GROUPS

Infants

Under 5 children

Children of school age

Women of child bearing age

PREVALENCE OF IDPREVALENCE OF ID

Region 0-4yr 5-12yrWomen

South Asia 56% 50% 58%Africa 56% 49% 44%Latin Am 26% 26% 17%Gulf Arabs 40% 36% 38%Developed 12% 7% 11%World 43% 37% 35%

ETIOLOGYETIOLOGY

• Inadequate intake of iron & of food, which enhances iron absorption.

• High intake of inhibitors of iron absorption

• Hookworm infestation.

• Blood loss (heavy menses & use of aspirin & NSAID).

• High fertility rate in womem.

• Low iron stores in newborns.

DIETARY IRONDIETARY IRON

There are 2 types of iron in the diet; haem iron and non-haem iron

Haem iron is present in Hb containing animal food like meat, liver & spleen

Non-haem iron is obtained from cereals, vegetables & beans

Milk is a poor source of iron, hence breast-fed babies need iron supplements

IRON ABSORPTIONIRON ABSORPTION

Haem iron is not affected by ingestion of

other food items.

It has constant absorption rate of 20-30%

which is little affected by the iron balance

of the subject.

The haem molecule is absorbed intact and the iron is released in the mucosal cells.

IRON ABSORPTION (2)IRON ABSORPTION (2)

The absorption of non-haem iron varies greatly from 2% to 100% because it is strongly influenced by:

The iron status of the bodyThe solubility of iron saltsIntegrity of gut mucosaPresence of absorption inhibitors or

facilitators

INHIBITORS OF IRON ABSORPTIONINHIBITORS OF IRON ABSORPTION

Food with polyphenol compounds Cereals like sorghum & oats

Vegetables such as spinach and spices

Beverages like tea, coffee, cocoa and wine.

A single cup of tea taken with meal reduces iron absorption by up to 11%.

OTHER INHIBITORSOTHER INHIBITORS

Food containing phytic acid i.e. Bran, cereals like wheat, rice, maize & barely. Legumes like soya beans, black beans & peas.

Cow’s milk due to its high calcium &

casein contents.

INHIBITION-HOW?INHIBITION-HOW?

The dietary phenols & phytic acids

compounds bind with iron decreasing

free iron in the gut & forming

complexes that are not absorbed.

Cereal milling to remove bran reduces

its phytic acid content by 50%.

Promoters of Iron AbsorptionPromoters of Iron Absorption

Foods containing ascorbic acid like citrus fruits, broccoli & other dark green vegetables because ascorbic acid reduces iron from ferric to ferrous forms, which increases its absorption.

Foods containing muscle protein enhance iron absorption due to the effect of cysteine containing peptides released from partially digested meat, which reduces ferric to ferrous salts and form soluble iron complexes.

IRON ABSORPTION (3)IRON ABSORPTION (3)

Some fruits inhibit the absorption of iron although they are rich in ascorbic acid because of their high phenol content e.g strawberry banana and melon.

Food fermentation aids iron absorption by reducing the phytate content of diet

IRON TRANSPORTIRON TRANSPORT

Transferrin is the major protein responsible for transporting iron in the body.Transferrin receptors, located in almost all cells of the body, can bind two molecules of transferrin.Both transferrin concentration & transferrin receptors are important in assessing iron status.

STORAGE OF IRONSTORAGE OF IRON

Tissues with higher requirement for iron ( bone marrow, liver & placenta) contain more

transferrin receptors.Once in tissues, iron is stored as ferritin & hemosiderin compounds, which are present in the liver, RE cells & bone marrow.The amount of iron in the storage compartment depends on iron balance (positive or negative).Ferritin level reflects amount of stored iron in the body & is important in assessing ID.

IRON CYCLE IN THE BODYIRON CYCLE IN THE BODY

ROLE OF IRON IN THE BODYROLE OF IRON IN THE BODY

Iron have several vital functionsCarrier of oxygen from lung to tissuesTransport of electrons within cellsCo-factor of essential enzymatic reactions:

Neurotransmission

Synthesis of steroid hormones

Synthesis of bile salts

Detoxification processes in the liver

DIAGNOSIS OF IDADIAGNOSIS OF IDA

Clinical: symptoms (fatigue, dizziness , palpitations..etc) & signs (pallor, smooth tongue, Koilonychia, splenomegaly & dysphagia in elderly women).

Laboratory

Stainable iron in bone marrow

Response to iron supplements

LAB FINDINGS IN IDALAB FINDINGS IN IDA

• Microcytic hypochromic anaemia

• Low Hb level (< 11.0 g/dl)

• Low MCV, MCH, MCHC

• Low serum ferritin

• High RWD

• High iron binding capacity

• High erythrocyte protoporphyrin

Normal Blood FilmNormal Blood Film

MICROCYTESMICROCYTES

HYPOCHROMIAHYPOCHROMIA

Consequences of Iron DeficiencyConsequences of Iron Deficiency

Increase maternal & fetal mortality.

Increase risk of premature delivery and LBW.

Learning disabilities & delayed psychomotor development.

Reduced work capacity.

Impaired immunity (high risk of infection).

Inability to maintain body temperature.

Associated risk of lead poisoning because of pica.

MANAGEMENT OF IDAMANAGEMENT OF IDA

Blood transfusion if heart failure is eminent

IV or IM iron in pregnant women

Oral iron 3-5 mg Fe/kg/day

Treat underlying cause

Dietary education

PREVENTION OF IDAPREVENTION OF IDA

Dietary modification

Food fortification

Iron supplementation

PREVENTION OF IDA /2PREVENTION OF IDA /2

Diet & nutrition education

eat more fruits and vegetable

no coffee or tea with meals

programmes should be targeted to

at risk groups

reduce phytic content of cereals and

legumes by fermentation

PREVENTION OF IDA /3PREVENTION OF IDA /3

Short term approach: supplementation with iron tablets.

Long-term approach: food fortification with iron either for the whole

population (blanket fortification) or for specific target groups like infants. It requires no cooperation from users unlike taking iron supplements.

FOOD FORTIFICATIONFOOD FORTIFICATION

Iron compounds used in food fortification can be divided into 4 groupsFreely water soluble (ferrous sulphate, gluconate, lactate & ferric ammonium citrate).Poorly water soluble (ferrous fumarate, succinate

& saccharate).Water insoluble (ferric pyrophosphate, ferric orthophosphate & elemental iron).Experimental (sodium-iron EDTA & bovine Hb concentrate).

Which iron form to use?Which iron form to use?

The major factors governing the choice of iron compound include:BioavailabilityOrganoleptic problemsCostSafety

Ideally we should go for a safe, cheap, highly bioavailable iron, which causes no organoleptic side-effects

Which iron form to use?Which iron form to use?

• Freely water soluble iron are the most bio-available, but causes unacceptable colour & flavour change in many foods.

• Insoluble iron compounds are inert with no organoleptic effects but it is poorly absorbed

• Cost-wise elemental iron is the cheapest, ferrous sulphate costs 10 times more, but most expensive is EDTA

• Safety is of concern with EDTA & Bovine Hb only because of potential problems

COMMON PRACTICECOMMON PRACTICE

Ferrous sulphate is commonly used in Rx & prevention of IDA because of good absorption & high bioavailability, but it has its drawbacks

GIT disturbances & staining of teeth are frequentEffects on fortified foods may include:

Fat oxidation & rancidityColour changesMetallic tastePrecipitation

EXPERIMENTAL COMPOUNDSEXPERIMENTAL COMPOUNDSEDTA (Ethylene Diamine Tetra-Acetate)

molecule has 4 negative charges to which any metal can be attached to form stable complex. The metal incorporated into EDTA can be replaced by a metal of higher affinity or released at a certain PH.

Food is usually fortified by both Fe-EDTA

& Na or Ca EDTA.

HOW EDTA ACTS?HOW EDTA ACTS?

Fe EDTA is stable in the acidic PH of the stomach, but dissociate in the alkaline PH of the duodenum releasing ferrous ions ready to be absorbed. while the Na-Ca EDTA dissociate in the stomach releasing Na & Ca and taking iron from the food instead to form Fe EDTA which dissociate in the duodenum.

ADVANTAGESADVANTAGES OF OF USING USING EDTAEDTA

Iron absorption is 6 times greater than with ordinary methods even in the presence of inhibitors.

No need to add vitamin C or other promoters to enhance iron absorption.

No change in colour or flavour of food with EDTA even when stored for long time.

LIMITATIONS of EDTA USELIMITATIONS of EDTA USE

EDTA fortification is 7 times more expensive than ordinary fortification using iron salts.

Health care providers have little experience with this new technique.