Iron

Hertanto W Subagio

Iron (Fe)

Functions a key attribute of iron is

its ability to take up and release oxygen atoms and electrons. This allows it to participate in carrying oxygen in the blood and transferring electrons in the electron transport chain of the cell mitochondria

• Carrier of oxygen in the blood (Hb).

• Storage of oxygen in muscle (myoglobin)

• Involved in electron transport chain and production of ATP (cytochromes)

Sources

• Heme iron

- animal ( ± 30%)

• Non Heme iron

- vegetable, legumes etc.

Internal cycle of iron

Absorptioniron status regulated through absorption

Increase- Acid in stomach

- Heme iron

- High body demand

- Low body stores of iron

- Meat protein factors (MPF)

- Vit C (converts ferri to ferro)

Decrease- Phytic acid (dietary fibre)

- Oxalic acid

- Polyphenols (tea, coffee)

- Full body stores of iron

- Excess of other minerals (Zn, Mn,Ca)

- Reduction in stomach acid

- Antacid

Iron Absorption

Model of iron absorption

Iron in the intestinal lumen

Enterocytes in the crypts

Enterocyte along the villus

Intestinal iron absorption

Iron in the human body

Transport

- Transferrin is a protein that transports iron in the blood

- When iron stores are adequate all iron binding sites are saturated

-Transferrin can be used as an indicator of overload or deficiency

- Almost all cells in the body have transferrin receptor (TfR)

- Serum soluble Tfr (sTfR) is a good indicator of deficiency.

Sintesis Hemoglobin

Internalisasi besi

Serum transferrin receptor(sTfR)

Storage Ferritin is the primary store of iron

Iron not taken up by transferrin is stored as ferritin in

the intestinal wall (short term store)

also stored in the liver and spleen as ferritin

Hemosiderin is a stable iron-protein compound in the

liver that stores iron when iron exceeds the storage

capacity of ferritin.

Iron Losses average iron loss of 1 mg / day in men and post menopausal

women

sweat and urine = negligible

exfoliation of the skin and GIT

menstruation

Deficiency and excess

Deficiency

IDA – high prevalence Reduced cognitive

functioning Reduce capacity for

physical work Increased maternal

mortality Stages : normal- depletion of

storage- IDE – IDA.

Excess

Haemochromatosis – genetic disorders

Fe deposits cause cell damage in pancreas, liver and heart

Leads to diabetes, liver and heart failure

Tahap deplesi besi dan indikatornya

Table 1. Changes in Laboratory Test in Relation to progression

Of Iron Deficiency

SID IDE IDA Serum Ferritin D D D Serum TfR N I I Serum Iron N D D Total Iron Binding Capasity N I I Transferrin Saturation N D D Erythrocyte Protoporphyrin N I I Mean Cell Volume N N D Red Cell Distribution Width N N I Hemoglobin N N D Hematocrit N N D Adapted from Cook and Finch and Skikne et al, 1990. SID : Storage Iron Depletion IDA : Iron Deficient Erythropoiesis IDE : Iron Deficiency Anemia

Perubahan parameter pada

defisiensi besi

Diagnosis defisiensi besi berdasar feritin dan sTfR

Public health programs

supplementation

fortification

dietary modification

food processing :

reduce inhibitory factors

education

Fig.1. Elements of successful iron supplementation programs

Policy making

Monitoring and Evaluation

Tablet Supply Adequate budget Data Base Ordering number In target group + 25% surplus Timely ordering Distribution System

Delivery System Accessible to Target group Motivated, Well- Trained Approachable staff

Consumer demand Good Quality Supplements Communications To educate Public and Promote Program

Coverage Do intended

Recipients get Supplements?

Compliance

Do recipients take the supplements

Impact

Reduction of Iron Deficiency anemia

Elements of successful iron supplementation programs

Allen et al. 2000

Suplementasi besi gagal karena tingginya prevalensi kurang gizi

kronik dan defisiensi berbagai zat gizimikro lain

Broek dan Lestky 2000

Among anemic pregnant women only 53% showed biochemical evidence of iron deficiency.

That is the maximum proportion of people among whom anemia could be expected to respond to the administration of iron

Prevalensi defisiensi zat gizimikro pada kasus anemia

01020304050607080

vit A Besi Seng B12

Defisiensi besi belum tentu merupakan penyebab dominan anemia

Berapa % anemia yg bisa disembuhkan dengan suplementasi besi ?

Keterangan : Seng dan Cu tak diperiksa di Malawi dan Nepal

Prevalensi defisiensi zat gizimikro pada ibu hamil anemia di Karangawen, Malawi dan Nepal

Pola defisiensi zat gizimikro pada kasus anemia

3.70%

55.60%

37.00%

3.70%

besi besi+gm lain gm lain tdk defisiensi gm

Defisiensi gizimikro tunggal jarang terjadi

Apakah semua yg defisien besi bisa sembuh dg suplementasi besi ?

Perbandingan defisiensi zat gizimikro pada ibu hamil yg anemia di Karangawen dan Malawi

Causes of microcytic anemia

Langsung pakai obat tambah darah untuk mengatasi anemia ?

Perubahan kadar Hb ibu hamil yang mendapat suplementasi

besi