Trace Elements Flashcards
What are trace elements?
Minerals present in small amounts in living tissues (<1 µg/g wet tissue or <0.01% of body weight).
Which metals are NOT considered trace elements?
Selenium, halogens, fluoride, iodine
FISH
What are essential trace elements?
normal health, function, and development.
Deficiency leads to impairment but can be corrected with supplementation.
Often part of enzymes (metalloenzymes) or proteins (metalloproteins).
What is the difference between trace and ultratrace elements?
Trace elements: Found in mg/L concentration (e.g., iron, copper, zinc).
Ultratrace elements: Found in µg/L concentration (e.g., selenium, chromium, manganese).
What are the specimen requirements for trace element testing?
Urine, serum, plasma, blood, hair, and nail samples.
What factors affect pre-analytical variation in trace element testing?
Time of day
Food intake timing
Tobacco use
etc
What is the preferred tube for trace element collection?
Navy blue top tube (EDTA, serum)
What are the methods used to analyze trace elements?
- Atomic Emission Spectroscopy (AES)
- Atomic Absorption Spectroscopy (AAS)
- Inductively Coupled Plasma-Mass Spectrometry (ICP-MS)
- Quadrupole Mass Spectrometers
- High-Resolution Mass Spectrometers
What is the 1st, 2nd, and 3rd, abundant transition metals?
Iron, Zinc, Copper
How much iron is in the body?
3-5 g
Where is Iron primarily distributed in the body?
Where is Zinc primarily distributed in the body?
Where is Copper primarily distributed in the body?
Where is Cobalt primarily distributed in the body?
Fluoride?
IRON——————
RBCs (~2-2.5 g)
Myoglobin (~130 mg)
Tissues (~8 mg, enzyme activation)
Ferritin & hemosiderin (bone marrow, liver, spleen)
Plasma iron concentration: 3-5 mg
ZINC——————-
Body:
60% in muscle
30 in bone
10 others
Blood:
80% in rbc
17% plasma
3% in wbc
COPPER———————–
high conc: liver (10%), brain, heart, and kidneys
COBALT————
Muscle, liver, fats
CHROMIUM—————–
Liver, spleen, soft tissue, bone
FLUORIDE———————
95 IN BONES AND TEETH
What percentage of dietary iron is absorbed?
About 10% of 1 g/day
In what form must iron be to be absorbed?
A: Fe²⁺ (Ferrous)
What helps convert Fe³⁺ to Fe²⁺ for absorption?
A: - Vitamin C
Ferric reductases
What protein binds iron in the blood for transport?
What what is used for zinc transport?
What what is used for copper transport?
What what is used for chromium transport?
What what is used for magnesium transport?
molybdenum
- Transferrin
- albumin (65); a2 microglobulin (35)
- to liver: albumin, trascupein, LMW (portal system)
- Transferrin, albumin(also bound by beta, gamma, lipoproteins)
- transferrin, albumin, a2 macroglobulin
- a2 macroglobulin, rbc
What is the main function of iron in the body?
Oxygen transport and storage
Who is at high risk for iron deficiency?
A: - Pregnant women
Children & adolescents
Women of reproductive age
What is another name for iron overload?
A:
Hemochromatosis
What is a genetic cause of iron overload?
A: Hereditary hemochromatosis (HFE gene mutation)
What are clinical signs of iron overload?
A: - Skin hyperpigmentation
Liver cirrhosis
Diabetes
Cardiomyopathy
Hypogonadism & impotence
What are the treatments for hemochromatosis?
Therapeutic phlebotomy
Administration of chelators
Transferrin
What are the two types of iron overload?
: Hereditary hemochromatosis and secondary iron overload
What conditions can excess iron contribute to?
A: Arthritis, cardiac arrhythmia, impotence, liver cancer
What is the primary storage protein for iron?
A: Ferritin
What lab tests are used to evaluate iron status?
Serum iron, TIBC, ferritin, transferrin saturation
How is total iron content measured
Using serum samples with spectrophotometric methods
What does TIBC measure?
A: The total amount of iron that can be bound by transferrin
How is Serum iron calculated?
How is TIBC calculated?
How is percent saturation calculated?
TIBC= serum transferrin x 1.2521
(Total Fe ÷ TIBC) × 100
What does ferritin indicate?
A: Iron storage levels
How is transferrin affected in iron deficiency?
A: It is increased
Differences Between Apoferritin, Ferritin, Apotransferrin, and Transferrin
Key Differences:
Apoferritin vs. Ferritin → Apoferritin is empty, while ferritin stores iron.
Apotransferrin vs. Transferrin → Apotransferrin is empty, while transferrin carries iron in the bloodstream.
What is the primary form of dietary iron?
A: Mostly Fe³⁺ (ferric iron).
How is dietary Fe³⁺ absorbed in the intestine?
A: It is reduced to Fe²⁺ (ferrous iron) by reducing agents before absorption.
What happens to Fe²⁺ inside the intestinal cell?
A: It can be stored as ferritin (Fe³⁺ form) or transported into the blood.
What protein transports iron in the blood?
A: Transferrin, which binds Fe³⁺ to form transferrin (Fe³⁺)₂.
What happens to heme from degraded RBCs?
A: It is broken down into bilirubin and Fe³⁺, which can be recycled.
Liver hormone that regulates iron levels.
Inhibits iron absorption & release by degrading ferroportin.
Hepcidin
Transports iron into the blood.
Hepcidin degrades ferroportin, reducing iron release.
Ferroportin
↑ Hepcidin = ? Iron levels
↓ Hepcidin = ? Iron levels
↑ Hepcidin = ↓ Iron levels (risk of deficiency).
↓ Hepcidin = ↑ Iron levels (risk of overload).
What are the key biochemical functions of iron?
Oxygen Transport
Oxygen Diffusion
Enzymatic Functions
Thyroid Function
How does iron contribute to tissue damage?
A: Iron acts as a prooxidant and contributes to LADCNP
Lipid peroxidation
Atherosclerosis
DNA damage
Carcinogenesis
Neurodegenerative diseases
Production of free radicals
What are the key laboratory tests for evaluating iron status
- Packed cell volume
- Hemoglobin (Hb)
- RBC count and indices
- Total Fe and TIBC
- % Saturation
- Transferrin & ferritin
What are the key steps in the spectrophotometric procedure for measuring serum iron?
- Acidification – Fe³⁺ is released from transferrin.
- Reduction – Fe³⁺ is reduced to Fe²⁺ using reducing agents (ascorbic acid, etc.).
- Color Formation – Fe²⁺ complexes with reagents (ferrozine, ferene, or bathophenanthroline) to form a color reagent.
What is TIBC?
A: It is the amount of Fe that could be bound by saturating transferrin and other minor Fe-binding proteins in serum or plasma.
What is the procedure for measuring TIBC?
- Sample + Fe³⁺ (to saturate transferrin binding sites).
- Addition of MgCO₃ (to precipitate excess Fe³⁺).
- Centrifugation (to remove the precipitate).
- Supernatant is analyzed for transferrin
How is transferrin measured?
How is transferrin measured?
A: It is an indicator of nutritional status.
Transferrin
How is ferritin measured?
Immunochemical methods (IRMA, ELISA)
Chemiluminescent techniques
How does ferritin level change in different conditions?
Decreased in Iron Deficiency Anemia (IDA)
How does transferrin level change in different conditions
increased in IDA
unacceptable specimens for total iron content
oxalate, citrate, and EDTA
2nd to iron as the most abundant trace element in the body
ZINC
Treatment for Wilson’s Disease (2)
Wilson’s disease is a?
ZINC or MOLYBDENUM-COPPER complex
Copper Excess
Increased zinc by
animal proteins, amino acids, calcium, and unsaturated FA
decreased zinc by
intake of iron, taking zinc on an empty stomach, copper at high levels
Calcium → In moderate amounts, calcium competes with inhibitors (like phytates) that block zinc absorption, indirectly increasing zinc availability.
Unsaturated Fatty Acids → Help solubilize zinc in the gut, facilitating its absorption through the intestinal lining.
______________________________________________________________________________
Iron → Competes with zinc for DMT1 transport, blocking absorption.
Empty Stomach → Low stomach acid reduces solubility and absorption.
High Copper → Increases metallothionein, which traps zinc and prevents uptake.
Functions in zinc
cofactor, DNA and RNA, proteins, glucose, cholesterol, membrane, insulin function, growth factor.
Cofactor → Essential for over 300 enzymes, including digestive and antioxidant enzymes.
DNA & RNA Synthesis → Needed for cell division and repair.
Protein Synthesis → Helps build and fold proteins correctly.
Glucose Metabolism → Supports insulin function and blood sugar regulation.
Cholesterol Regulation → Involved in lipid metabolism and maintaining heart health.
Cell Membranes → Stabilizes membrane structure and protects against oxidative damage.
Insulin Function → Helps store and release insulin for blood sugar control.
Growth Factor → Supports hormones and cell growth, especially in development and wound healing.
growth retardation
testicular atrophy
reduced taste perception
zinc deficiency
pregnancy
lactation
alcoholism
poor zinc nutrition
impaired dark adaptation
alopecia
emotional instability
zinc deficiency in adolescents
impaired intestinal absorption and transport of zinc
Facial and Diaper rash
Acrodermatitis enteropathica causes zinc deficiency
> 60mg/day of dietary zinc may result in
basta excess zinc causes
copper depletion by blockage of intestinal absorption
exposure to ZnO fumes and dust. This shows symptoms of somewhere in respiratory problems, fever, pains in leg and chest and vomitting.
Zinc fume fever
zinc decreases in after meals, infection and inflammation, steroid, pregnancy, and hypoalbuminemia
After Meals → Food delays zinc absorption due to competition with other nutrients.
Infection & Inflammation → Zinc shifts to tissues for immune response; increased IL-6 lowers blood zinc.
Steroids → Increase zinc excretion through urine.
Pregnancy → Higher demand for fetal growth reduces maternal zinc levels.
Hypoalbuminemia → Zinc binds to albumin, so low albumin means less circulating zinc.
3rd most abundant trace element
copper
copper has how many oxidation states? and what is the most stable?
4 oxidation states, Cu(+2) being the most stable
which trace elements function as cofactors?
all except cobalt at fluoride
____ and ____ competes with copper for intestinal absorption.
Shared Transporters:
Zinc & Copper → Both bind to metallothionein in intestinal cells (storage). High zinc induces metallothionein, which traps copper and reduces its absorption.
Iron & Copper → Both use DMT1 (Divalent Metal Transporter 1), leading to competition. High iron intake can block copper uptake.
other copper containing proteins
metallothionein and clotting factor V
which trace elements are a component for clotting factor?
ELECTROLYTES
Calcium (Ca²⁺) → Essential for the activation of clotting factors (Factors II, VII, IX, and X).
Magnesium (Mg²⁺) → Helps regulate platelet function and clotting enzyme activity
TRACE ELEMENTS
Zinc (Zn²⁺) → Supports platelet aggregation and is a cofactor for enzymes like factor XIII (fibrin stabilization).
Copper (Cu²⁺) → Required for ceruloplasmin, which plays a role in iron metabolism and blood clotting.
What trace elements are excreted in bile
COPPER, MANGANESE, MOLYBDENUM pero nakalagay don ay with ZINC at SELENIUM
what is the relation of copper deficiency in zinc and iron
copper deficiency is caused by zinc and iron
what is the defective transport of copper from mucosal cells?
Menke’s disease
kinky/steely/twisted hair
Menke’s disease
Wilson’s disease
excess copper
give one clinical findings that is found in Wilson’s disease
kayser-fleischer rings
give one treatment to wilson’s disease
zinc acetate
diurnal variation trace elements
Iron and zinc peak in the morning, while copper peaks later in the day.
what type of copper is a good index for copper status
Ceruloplasmin
which trace elements is a constituent of Vit B12, involved in folate and erythropoiesis
Cobalt
Megaloblastic anemia
Cobalt since it is a constituent to Vit B12
What are the two main types of Chromium valency states?
+3 and +6
which chromium is used in GTF (Glucose Tolerance Factor)
Cr+3
which chromium is better absorbed?
Cr+6
biologically active Chromium
Cr+3
Toxic but useful chromium?
Cr+3
Chromodulin LMWCr enhances the response of ___ receptors for ____ uptake
what trace elements is also related to it?
insulin function and performace BASTA INSULLIIINNNNN
severe dermatitis
Chromium
Most widely used of the pharmacologically beneficial trace elements
Fluoride
Bone function is related to
Calcium, vit D, fluoride, and parathyroid hormone
Mottled enamel
Fluoride toxicity
Used in steel production or allow
Manganese (ferromanganese)
fuel supplement in manganese
methyl cyclo penta dienyl manganese tricarbonyl
which manganese is only found in biological systems
Mn2+ and Mn3+
what is excreted in bile and pancreatic secretions
manganese
manganese containing enzymes
arginase
pyruvate carboxylase
superoxide dismutase
glycosyl transferase
allergic dermatitis with eczema
chromium
mande up of ___ ferromanganese
80%
manganese is non specific so it can be replaced by
Mn, Cu, Fe
parkinson’s disease
manganese toxicity
wide open fixed staring eyes
locura manganica
GLUCOSE AND CHOLE METABOLISM IS RELATED TO WHAT TRACE ELEMENTS
ZINC AT CHROMIUM
molybdenum occurs naturally as
molybdenite, wulfenite, powellite
COMPULSIVE LAUGHING OR CRYING
Manganese
which trace element crosses the placenta
Molybdenum
enzymes related to molybdenum
what are the enzymes related to manganese
xanthine
aldehyde
sulfite
arginase
Pyruvate carboxylase
superoxide
glycosyle
trace elements similar to those of sulfur
selenium
constituent of glutathione peroxidase
constituent vit 12
Vit C
Vit D
closely associated to Vit E
Selenium
Cobalt
Iron - reductase
Fluoride
Selenium
Ingested selenium compound
selenate
selenocysteine - most important biologically active compound
selenomethione - found in plants
selenium compound in plants
selenium compound that is most important biologically active compound
selenomethione
selenocysteine
Selenocysteine containing protein
Glutathione peroxidase
Iodothyronine
Thioredoxin
Selenoprotein P
major selenium containing protein in blood plasma
Selenoprotein P
Selenium that converts selenium t4 to t3
Iodothyroxine
reduction fo thiodexin
Thioredoxin reduction
selenium that removes an oxugen atom from peroxide adn lipidhydroxide
glutathione peroxidase
Keshan Disease
severe deficiency of Selenium
Kashin beck disease
severe deficiency of selenium
Garlicky breath
toxicity of selenium
