ROLE OF IRON IN HUMAN HEALTH
Arun Malik and Hariom Yadav
NATIONAL AGRI-FOOD BIOTECHNOLOGY INSTITUTE, MOHALI , PUNJAB, INDIA
Email: yadavhariom@gmail.com
WHY DO WE NEED IRON
 Iron is a mineral found in every cell in
the body.
 It is vital for both physical health and
mental well-being.
 Iron has three main functions :
 carrying oxygen from the lungs to the rest of
the body.
 maintaining a healthy immune system.
(Body protects itself from antigens, which includes virus, bacteria and
foreign substances that make sick)
 aiding energy production.
(Iron is constituent of several enzymes including : iron catalase,
peroxidase, and cytochrome enzymes)
INSUFFICIENT DIETARY IRON CAN
RESULT IN IRON DEFICIENCY
fatigue
lethargy
more frequent infections
reduced resistance to cold
impaired learning
Hypoferrimia
TYPES OF IRON
There are two types of iron in food:
 Heme iron, derived from the hemoglobin and myoglobin
found in meat tissue
 Non-heme iron, derived mainly from cereals,
legumes, fruit and vegetables.
HEME IRON
 Heme iron is found only in animal foods. The iron in
meat is approximately 40% heme iron and 60% non-heme
iron. Plant foods do not contain any heme iron .
 Heme iron is well absorbed and relatively unaffected by other
factors .
 It is influenced to some extent by the body’s iron stores.
The average absorption of heme iron in meat is about 25%.
NON-HEME IRON
 Non-heme iron is found in plant foods.
 It is not as well absorbed as heme iron and is affected
by both the iron status of an individual, and components
in foods eaten at the same time.
 Absorption of non-heme iron can vary from under 1% in
an individual with replete stores to 20% in an individual
with depleted iron stores .
 Generally non-heme iron absorption is less than 5%.
VITAMIN C IMPROVE NON-HAEM
IRON ABSORPTION
 Vitamin C can increase the absorption of non-haem
iron by two to three times.
 There is a dose-related effect; the more vitamin C in a meal, the greater
the iron absorption - up to a limit of around 100mg vitamin C .
 Vitamin C is found in fruit and vegetables. Both heat and air reduce
vitamin C content, so care should be taken when cooking and storing fruit
and vegetables.
FACTORS AFFECTING NONHAEM IRON ABSORPTION
IMPROVE ABSORPTION
INHIBIT ABSORPTION
CAULIFLOWER
TANNINS IN TEA
TOMATOES
DIETARY FIBRE
KIWIFRUIT
SOY PROTEINS
MEAT, FISH, POULTRY
PHYTATES IN WHOLEGRAINS
TAMARILLOS
POLYPHENOLS
CITRUS FRUIT (ORANGES, GRAPES) OXALATE
IRON SUPPLEMENTS
 Iron supplements should only be used when advised
by a dietitian or prescribed by a medical practitioner for
diagnosed iron deficiency.
 Iron supplements should be used
cautiously as they may interfere with the absorption of
other nutrients such as zinc and calcium.
IRON ABSORPTION IN HUMAN BODY
HEME IRON UPTAKE
HEME IRON
HEME IRON
TRANSPORT
ENDOCYTOSIS
FERROUS IRON
LIBERATED WITH IN ENDOSOME
NON-HEME IRON UPTAKE
FERRIC IRON
REDUCED BY
ASCORBIC
ACID
INCLUDE
DUODENAL
CYTOCHROME
B
FERROUS IRON
TRANSFERRIN
FERROPORTIN
HEPHAESTIN
HEPCIDIN REGULATES IRON
ABSORPTION
 Hepcidin is 25 amino-acid peptide hormone.
 Hepcidin is synthesized by hepatocytes.
 Hepcidin binds to ferroportin1 and causes
its internalization and degradation thereby
decrease iron transfer to blood.
 Hepcidin function to regulate(inhibit)
iron transport across gut mucosa there by
preventing normal iron level.
HOW HEPCIDIN REGULATES IRON
ABSORPTION
Hepcidin regulation by
Inflammation
 IL-6 a prominent inducer of hepcidin, through
STAT-3 dependent transcriptional mechanism.
◦
Other cytokines may also induce hepcidin independent of IL-6.
 Macrophage also express hepcidin in response to
micobial stimulation.
◦
Hepcidin may function in autocrine manner to degrade macrophage
ferroportin,
causing local retention of iron in macrophages.
EFFECT OF MUTATION OF
SPECIFIC PROTEINS
IRON OVERLOAD
IRON DEFICIENCY
Hypotransferrinanemia - recessive
TMPRSS6 mutation - IRIDA
HFE gene mutation
Ferroportin mutation – autosomal
dominant
Hepcidin mutations
Hemojuvelin mutations
H ferritin mutation - dominant
HUMAN DISEASE
ASSOCIATED WITH IRON
CARDIOVASCULAR
DISEASE
HEMOCHROMATOSIS
PROTEIN HFE
IRON
THE FRIEDRICH’S
ATAXIA PROTEIN
MELANOTRANSFERRIN
CARDIOVASCULAR
DISEASE
 Heme
iron
are
associated
cardiovascular diseases(CVD) risk.
with
Such as saturated fats or other dietary and
lifestyle factors associated with meat intake.
HEMOCHROMATOSIS
PROTEIN HFE
 Hereditary hemochromatosis is inherited disorder that results
from an excess accumulation of iron in many organs which is
manifested by liver cirrhosis, cardiomyopathy, diabetes
mellitus, arthritis, skin pigmentation and if left untreated death.
 The gene responsible for hereditary hemochromatosis is
closely linked to locus for the human leukocyte antigens and
has been identified as major histocompatibility complexencoded class-1 like HFE.
 Hereditary hemochromatosis is more prevalent than other
inherited diseases such as cystic fibrosis, sickle cell anemia,
phenylketonuria and Tay-Sachs disease.
THE FRIEDRICH’S
ATAXIA PROTEIN
 Farataxin is mitochondrial protein which involved in
mitochondrial iron homeostasis.
 Farataxin deficiency is due to hyper-expansion of
polymorphic GAA trinucleotide repeat which
inhibits transcription and falls in levels of mature
faratxin mRNA.
 Farataxin deficiency in patients leads to develop
Friedrich’s ataxia which is a progressive
neurological disorder and cardiomyopathy and
finally leads to death.
MELANOTRANSFERRIN
• Melanotransferrin reported to expressed in amyloid
plaques in brain of patients with Alzheimer’s
disease.
• Melanotransferrin mRNA widely expressed in tissue
and also in salivary glands.
• Levels of melanotransferrin mRNA do not change in
presence or absence of an iron chelators or iron
source.
• Functional studies shown that melanotransferrin
transports iron from iron-citrate complexes but not
from iron-transferrin complex.
• Melanotransferrin has minor role in iron uptake from
iron citrate complexes.
IRON BIOAVAILABILITY IN
VEGETABLES
VEGETABLES
IRON IN /mg
Mushroom, pleurote
1.74
Potatoes
0.76
Cabbage, Collards
0.19
Cabbage, Green
0.59
Roasted Pumpkin and Squash Seeds
15
Spinach
2.71
Sesame Butter(Tahim) and Seeds
14.8
Sundried Tomatoes
9.1
Dried Apricot
2.2
Lentils
6.20
IRON BIOAVALABILITY IN
FRUITS
FRUITS
IRON IN/mg
Apples, without skin
0.07
Blackberries
0.57
Dates
1.15
Pears, without skin
0.25
Pineapple
0.37
Raspberries
0.57
IRON BIOAVALABILITY IN GRAINS
GRAINS
SERVING
IRON IN /mg
Wheat Flour, White
Cake, Enriched
1 cup
10.03
Wheat, Soft White
1 cup
9.02
Wheat, Hard White
1 cup
8.76
Sorghum
1 cup
8.45
Corn flour, Masa,
Enriched White
1 cup
8.22
Corn flour, Masa,
Enriched Yellow
1 cup
8.22
Millet
1 cup
6.02
Oats
1 cup
7.36
Quinoa
1 cup
2.36
Rice Bran, crude
1 cup
21.88
MORE HEME IRON RICH
FOODS
Meat
IRON IN/mg
Beef Lean Chuck
2.9mg
Turkey Meat(Dark)
2.3mg
Chicken Leg(Roasted)
1.3mg
Tuna(Bluefin)
1.3mg
Halibut
1.3mg
Pork Chops(Loin)
1mg
White Tuna
0.9mg
Shrimp(Prawns/Camarones)
1mg
Liver
30.5mg
Clams, Oysters and Mussels
28mg
RECOMMENDED DIETARY
IRON INTAKE
IRON mg per Day
Infants (7-12 months)
11
Children (1-13 years)
8-10
Boys (14-18 years)
11
Girls (14-18 years)
15
Women (19-50 years)
18
Pregnant Women
27
Breastfeeding Women
9-10
Women over 50 years
8
Men over 19 years
8
CONCLUSION
 Heme and non-heme iron are absorbed differently.
 Meat, fish, poultry and vitamin C improve the absorption
of non-heme iron.
 Tannin, oxalate, phytates and dietary fibre all reduce the
absorption of non-heme iron.