Mineraler och spårämnen - Kap 9

Question 1

Total body iron content

Answer 1

approximately 3 – 5 g
60% - haemoglobin
25% - storage in the liver

Question 2

Vad gör järn?

Answer 2

Functions:
• transport of oxygen and electrons
• a component of several tissue enzymes such as
cytochromes that are critical for energy production and
enzymes involved in the immune system

Question 3

Var finns järn?

Answer 3

Haem iron
• primarily from hemoglobin and
myoglobin in animal protein
sources
• readily bio-available, since it is
absorbed intact within the
porphyrin ring
• not influenced by most inhibitory
factors in the diet. 

• in enriched cereals and pasta, beans,
and dark green leafy vegetables
• must be solubilized and hydrolysed
before absorption is possible
• markedly affected by inhibitory ironbinding
ligands
• enhancers : animal protein, copper,
and vitamin C
• Inhibitors: vegetable protein, phytic and oxalic acids, zinc, calcium, tea, coffee

Question 4

Hur tas järn upp?

Answer 4

Heme: taken up by heme carrier
protein (HCP) into an intestinal
intracellular vesicle
Acted on by heme oxygenase to
release iron
Non-heme: Fe3+ reduced to Fe2+
by duodenyl cytochrome B
(DCYTB) in the intestinal lumen
and taken up by divalent metal
transporter (DMT1)

Question 5

Iron deficiency

Answer 5

Anemia - – pathologic condition, accompanied by decrease in the
level of hemoglobin and the quantity of erythrocytes per unit of
volume of the blood

Question 6

Iron overdose

Answer 6

• Severe iron overdose can cause acute hepatic necrosis and lead to multiorgan
failure and death
• Fatal dose – 180-300 g/kg of body weight

Question 7

Total body zinc content approximately

Answer 7

2 – 3 g
60% in muscles
30% in skeleto

the second most abundant trace metal in the human body

Question 8

zink - Function:

Answer 8

• In the human body, there are more than
300 different enzymes that require zinc to
function normally! (superoxide dismutase,
alcohol dehydrogenase…)

Question 9

Zinc in food

Answer 9

• Zinc from animal and plant-originated
food are mainly incorporated into the
organic molecules (proteins)
• Some zinc is present in inorganic
forms (in some plant foods)
• No evidence for separate ways of
absorption

Question 10

Zinc absorption

Answer 10

• Absorbed in the small intestine
• Release to blood bound to albumin
• High intake of zinc induce synthesis of metallothionein
• Enhancer of zinc absorption:presence of animal protein
• Inhibitor of zinc absorption: phytate

Question 11

Total body copper content approximately

Answer 11

50 – 120 mg

40% in muscles 15% in liver 10% in brain 6% in blood

Question 12

coppar - Function:

Answer 12

Part of enzymes - cuproenzymes (participate in redox
reactions)
Examples: amine oxidase, superoxiddismutase, multi-copper
oxidases —ceruloplasmin, hephaestin and zyklopen

Question 13

Role of copper in iron metabolism

Answer 13

• Copper-containing ceruloplasmin is required for iron
transport to the bone marrow for red blood cell formation
• Ceruloplasmin was first purified from blood plasma by
Holmberg and Laurell in 1948

Question 14

The intake of copper in the Nordic

countries

Answer 14

varies between 1.0 mg/d

and 2.0 mg/d

Question 15

Var finns coppar?

Answer 15

beef lever, mörk choklad, apricots, sunflowerseed

The major sources of excess copper are:
• Copper water pipes, especially when attached to a
water softening system - överdos

Question 16

Factors influce copper absorption

Answer 16

Excess of iron
Excess of zinc
Some aminoacids
(histidin, cysteine)
Presence of citrate

Question 17

Total body manganese content approximately

Answer 17

10 – 20 mg
Higher concentration in bone and in organs
rich in mitochondria, such as the liver,
pancreas, and kidney
Low in muscles and plasma

Question 18

Function:

mangansese

Answer 18

• Catalytic cofactor for arginase, pyruvate carboxylase, and
mitochondrial superoxide dismutase (SOD).
• A specific or unspecific activator for a large number of
other enzymes, some of which participate in the
synthesis of proteins, mucopolysaccharides, and
cholesterol.

Question 19

Manganese absorption

Answer 19

• Only about 3 – 5% of an ingested dose is absorbed
• Gender differences in Mn absorption, men absorbing significantly
less Mn compared to women probably due to higher serum ferritin
concentrations in men

Question 20

Manganese deficiency

Answer 20

• Only in experimental animals (changes in

skeleton, slow growth, fatty liver)

Question 21

Manganese overdose

Answer 21

• From excess respiratory or dietary
exposures
• Neurotoxicity - oxidativ stress, inhibition av complex 1 i elekrontransportkedjan

Question 22

Total body selenium content approximately

Answer 22

13 – 20 mg

• 30% is in the liver, 15% in kidney, 30% in muscle, 10% in blood plasma

Question 23

Selenium functions

Answer 23

• Part of enzymes
• Co-factor in antioxidant activities and thyroid hormone
metabolism

Question 24

Selenium absorption and metabolism

Answer 24

• Selenium in food is mainly in organic form
• Selenium absorption does not appear to be under homeostatic control
For example, absorption of the selenite form of selenium is greater than
80% whereas that of selenium as selenomethionine or as selenate may
be greater than 90%
• Therefore, the rate-limiting step determining the overall availability of
dietary selenium is not likely to be its absorption but rather its
conversion within tissues to its metabolically active forms

Question 25

Selenium deficiency

Answer 25

• Selenium deficiency is rare
• Selenium deficiency may contribute synergistically
with iodine deficiency to the development of goiter
and hypothyroidism
• In China, growing children with selenium deficiency
may develop chronic osteoarthropathy (Kashin-Beck
disease).
• Diagnosis of selenium deficiency is made clinically or
sometimes by measuring glutathione peroxidase
activity or plasma selenium, but neither of these tests
is readily available.

Question 26

Selenium overdose

Answer 26

• In areas with high levels of selenium
• Symptoms of selenosis: garlic odor on the breath, gastrointestinal
disorders, hair loss, sloughing of nails, fatigue, irritability, and
neurological damage.
• Extreme cases of selenosis can result in cirrhosis of the liver,
pulmonary edema, and death.
• Exceeding the Tolerable Upper Intake Level of 300 micrograms
per day

Question 27

Cobalt - funktion och källa

Answer 27

Part of Vitamin B12 (cobalamin)
Meat, liver, kidney, clams, oysters, and milk
all contain some cobalt. Ocean fish and
sea vegetables have cobalt, but land
vegetables have very little; some cobalt is
available in legumes, spinach, cabbage,
lettuce, beet greens, and figs.

Question 28

Cobalt overdose

Answer 28

• Toxicity can occur from excess inorganic cobalt found as
a food contaminant.
• Beer drinker’s cardiomyopathy (enlarged heart) and
congestive heart failure have been traced to cobalt
introduced into beer during manufacturing. Increased
intake may affect the thyroid or cause overproduction of
red blood cells, thickened blood, and increased activity in
the bone marrow.
• Deficiency of cobalt is not really a concern if we get
enough vitamin B12.

Question 29

Vilka andra finns?

Answer 29

Chromium
Fluoride
Iodine