Trace elements
Ashok Joshi
Elements of Life
Most abundant, essentaa or aaa organisms: C, N, O, P, S, H
Less abundant, essentaa or aaa organisms : Na, Mg, K, Ca, Ca
Trace aeveas, essentaa or aaa organism: Mn, Fe, Co, Cu, Zn
Trace aeveas, essentaa or some organisms: V, Cr, Mo, B, Aa, Ga, Sn, Si, As, Se, I,
Classifcaton
• There are two categories of minerals essental
within the body,
1. Macro-minerals
2. Micro-minerals
Macro-mineraas
• Calcium
• Phosphorous
• Potassium
• Magnesium
• Sulfur
• Sodium
• Chaoride
The Trace Mineraas: An Overview
• Inorganic atoms or molecules
• Microminerals or trace elements
• < 100 mg/day needed
• Present in body tssues at concentratons <50
mg/kg (50 ppm)
Iron
• Most common nutrient defciency in the world
Functons
– Oxygen transport via hemoglobin
Thus, necessary for ATP producton!
– Essental component of many enzymes
– Immune functon
– Brain functon
Iron defciency/toxicity thought to slow mental
development in kids.
Heme containing proteins
• Hemoglobin: transport of oxygen in blood
• Myoglobin: storage of oxygen in muscle
• Cytochrome P450 groups: involvement in
oxygen transport chain
Iron in the Body
• Normal 70 kg adult male has 3-4 g
Iron Requirements
• Requirement of iron varies according to age, sex,
weight and state of health
• An adult male : approx. 10 mg/day
• Adult female : 20 mg/day
• Pregnant women: 10 mg/day
• Lactatng mothers: 25 to 30 mg/day
• Children: 10 to 15 mg/day.
Iron Absorpton
Iron ingest in diet in either as
• Non-heme or heme iron
• Heme iron
– Chemical modifcaton not need
• Nonheme iron
– Reduced to ferrous form
Iron Absorpton
• Absorpton of nonheme iron: enterocytes of
the proximal duodenum
• Transport across
Brush border
Basolateral membrane
Iron Absorpton
Iron Absorpton
• Inorganic dietary iron in the ferric state (Fe3+) is
reduced to its ferrous form (Fe2+) by a brush border
membrane-bound ferrireductase, duodenaa
cytochrome b
• The transfer of iron across the apical membrane of
the enterocytes is accomplished via the divaaent
metaa transporter 1 (DMT1)
Nonheme iron transport in enterocytes
Iron Absorpton
• Ferrous iron is converted back to ferric form
inside the cell and stored in ferritn Around
4000 molecules are stored in one ferritn When
the storage is sufcient, ferrous ions leaves the
cells via through ferroprotein It is oxidized to
ferric iron by membrane associated protein,
hephastein
Iron Circulaton, Uptake Into Cells, & Storage
• Trans errin
– Delivers iron to body cells
– Transferrin receptors
• Iron storage compounds
Ferritn
• Main storage form
Hemosiderin
• Long-term storage
Iron Excreton
• Human body has no mechanism for excretng iron
• A one way metal
• Absorpton of iron at the level of intestnal mucosal cells is
the only way of controlling body iron level
• Loss of iron from body happens in bleeding, shedding of
epithelial cells of skin and mucosa
• Menstrual bleeding makes females more prone to iron
defciency anemia
WHO 2008
• Gaobaa anaemia prevaaence and number o individuaas
afected
• Globally, anaemia afects 1.62 billion people (95% CI: 1.50–1.74
billion), which corresponds to 24.8% of the populaton (95% CI:
22.9–26.7%). The highest prevalence is in preschool-age
children (47.4%, 95% CI: 45.7–49.1), and the lowest prevalence
is in men (12.7%, 95% CI: 8.6–16.9%). However, the populaton
group with the greatest number of individuals afected is non-
pregnant women (468.4 million, 95% CI: 446.2–490.6).
Clinical aspects
A. IRON DEFICIENCY:
• Iron storage depleton
• Iron defciency
• Iron defciency
). anaemia: hypochromic microcytc
anaemia
B. IRON OVERLOAD
• Haemochromatosis
• Haemosiderosis
Mild Iron Defciency
• Signs
– Fatgue
– Impaired physical work performance
– Behavioral abnormalites
– Impaired intellectual abilites in children
– Body temperature regulaton
– Influences immune system
Severe Iron Defciency: Iron-Defciency
Anemia
• Microcytc hypochromic anemia
– Small, pale red blood cells
– Inability to produce enough heme
– Decreased ability to carry oxygen
– Decreased ATP synthesis
Iodine
• Functon
– Essental component of
thyroid hormones
• Important for regulaton
of body temperature,
basal metabolic rate,
reproducton and growth.
• Regulaton in body
– Almost all is absorbed.
– Excess removed in urine.
Dietary Sources
• Seafoods
• Milk/dairy products
• Iodized salt
Iodine Defciency
• Goiter (less severe)
– Enlarged thyroid gland due to body’s atempt to
increase thyroid hormone producton
• Cretnism (more severe)
– Severe iodine defciency during
pregnancyserious problems in baby
• Stunted growth, deaf, mute, mentally retarded.
Absorpton, Metabolism, & Regulaton of
Iodine
• Absorbed in small intestne & stomach
• Taken up by thyroid gland
• Thyroid-stmulatng hormone regulates uptake
Functons of Iodine
• Component of:
– Thyroxine (T4)
– Triiodothyronine (T3)
• Regulates energy metabolism, growth,
development
• Signs of defciency
– Severe fatgue
– Lethargy
Acrodermatts Enteropathica
• Zinc defciency even
with adequate amounts
of dietary zinc
• Supplementaton
• Infants
– Growth failure
– Red/scaly skin
– Diarrhea
• Human Genome Project
Fluoride
• 99% is found in bones
and teeth
• Functon
– to promote
mineralizaton of
calcium and
phosphate.
– Inhibits bacterial
growth in
mouthdecreases
cavity formaton.
Functons of Fluoride
• Part of bone & teeth matrix
• Stmulates maturaton of osteoblasts
• Topical applicaton decreases bacteria in
mouth
– Fewer cavites
Copper
• Essental trace element
• Metal cofactor for variety of enzymes
Amine oxidase
Copper-dependent superoxide dismutase
Cytochrome oxidase
Tyrosinase
Clinical aspect
Wilson’s Disease
Defectve biliary excreton of Cu Kayser- Faeischer Ring
Accumulaton of copper in liver
Spillage into circulaton
Increase in blood and urinary copper
