Week 7 Flashcards
(43 cards)
Introduction to trace elements
Trace elements
Micro-nutrients are chemical elements required in minute amounts
Usually as part of a vital element.
There are 19 trace elements divided into three groups (WHO
classification):
Essential elements
Essential Trace element
They are :
1. zinc (Zn),
2. copper (Cu)
3. selenium (Se)
4. chromium (Cr)
5. cobalt (Co)
6. Manganese (Mn)
7. molybdenum (Mo).
Copper
3rd most important trace element
Copper combines with certain proteins to produce enzymes
that act as catalysts to help several body functions.
Some help provide energy required by biochemical
reactions.
Others are involved in the transformation of melanin for
pigmentation of the skin and still others help to form cross-
links in collagen and elastin and thereby maintain and repair
connective tissues.
This is especially important for the heart and arteries.
Copper Metabolism
Copper is carried mostly in the bloodstream on a plasma protein ( a blood protein ) called ceruloplasmin.
When copper is first absorbed in the
gut it is transported to the liver bound
to albumin.
Copper is found in a variety of
enzymes, including the copper
centers of cytochrome c oxidase and
the enzyme superoxide dismutase
(containing copper and zinc).
In addition to its enzymatic roles,
copper is used for biological electron
transport.
Copper’s Charge States
Copper forms two series of
compounds:
copper (I/cuprous)
copper (II/cupric) compounds.
Metabolic Functions of Copper
Is component of a cofactor for approximately 50
different enzymes. These enzymes need copper to
function properly.
Is essential for iron absorption and transport.
Iron is needed to make haemoglobin, a main
component of red blood cells. Therefore, copper
deficiency is often linked to iron-deficiency anemia.
Is required to build elastin and collagen, which are an
important component of bones and connective tissues.
Therefore, copper is believed to protect the bones and
joints against degeneration and osteoporosis.
Is required for melanin (pigment) production. People
with copper deficiency may have pale skin and hair.
Is a key mineral for the immune system. Copper
promotes wound healing.
Haemoglobin
Haemoglobin is the iron-containing oxygen-
transport metalloprotein in the red blood cells of the
blood.
Elastin
Elastin, is a
protein in
connective tissue
that is elastic and
allows many
tissues in the body
to resume their
shape after
stretching or
contracting.
Collagen
Collagen is the
most abundant
protein in
mammals
Copper
Deficiencies
copper deficiency produces an
extensive range of symptoms. These
symptoms include:
- iron deficiency anemia
- osteoporosis
- ruptured blood vessels
- neutropenia
- joint problems (arthritis)
- brain disturbances
- elevated LDL cholesterol and reduced HDL
cholesterol levels
- increased susceptibility to infections due to
poor immunity
- loss of pigment in the hair and skin (Menkes’
Syndrome)
- poor thyroid function
- irregular heartbeat
- intolerability of glucose
Osteoporosis
Copper works with vitamin C to help
make a component of connective
tissue, elastin.
Osteoporosis is defined as a disease in
the bone in which the bone mineral
density is reduced, bone
microarchitecture is disrupted, and the
amount and variety of non-collagenous
proteins in the bone is altered.
Osteoporotic bones are more at risk of
fracture.
Neutropenia
Neutropenia is a hematological (study of blood) disorder characterized by an abnormally low number of neutrophil granulocytes (a type of white blood cell and serves as the primary defense against infections by destroying bacteria in the blood).
Arthritis
Arthritis is inflammation of
the joints. Copper’s anti-inflammatory actions may help in reducing arthritis symptoms.
Menkes’ Disease
Menkes disease (also called the kinky hair disease or
Menke’s kinky hair syndrome) is a disorder that affects
copper levels in the body.
It is characterized by sparse and coarse hair, growth
failure, and deterioration of the nervous system.
Onset of Menkes syndrome typically begins during
infancy.
Signs and symptoms of this disorder include weak
muscle tone (hypotonia), sagging facial features,
seizures, mental retardation, and developmental
delay.
The patients have brittle hair and metaphyseal
widening. In rare cases, symptoms begin later in
childhood and are less severe. It is a X-linked
recessive disorder, therefore males have the disease,
while females are carriers.
Copper Toxicities
Copper in excess amounts is usually caused by over supplementation.
Excessive intake of copper can cause:
- abdominal pain and cramps
- diarrhea
- liver damage
The toxic effects of high tissue levels of copper are seen in
patients with Wilson’s disease
A genetic disorder characterized by copper accumulation
in various organs due to the inadequate synthesis of
ceruloplasmin (the protein that transports copper through
the blood) by the liver.
Wilson’s disease primarily effects the liver, kidneys,
and brain causing degenerative physiological changes
(including cirrhosis of the liver, muscular rigidity and
spastic contraction, and emotional disturbances) that
are fatal if untreated.
The treatment of Wilson’s disease involves avoidance
of foods rich in copper and any supplements
containing copper and drug treatment with chelating
agents that remove the excess copper from the body.
Zinc
Second most abundant trace element
Cofactor – DNA polymerase, alkaline phosphatase,
carboxypeptidase
Regulate- growth, immune system, collagen synthesis,
wound healing, bone metabolism, reproduction, taste, smell
& vision
Manifestations of Zinc deficiency
Skin lesions (acrodermatitis)
Growth retardation
Anorexia
Poor wound healing
Decreased night vision
Hypogonadism
Impaired immune function
Diarrhea
Depressed mental function
Teratogenesis
Zinc Metabolism
70% bound to albumin in serum
Absorbed mainly in small bowel
Zinc and cell mediated immunity
Play a central role in the immune system
and Zn deficient individuals experience
increased susceptibility to a variety of
pathogens.
Affects multiple aspects of the immune
system from the barrier of the skin to
gene regulation within lymphocytes.
Zn is crucial for normal development
and function of cells mediating non-
specific immunity such as neutrophils
and natural killer cells.
Zn deficiency also affects development
of acquired immunity by preventing
both the outgrowth and certain
functions of T cells such as activation,
Th1 cytokine production, and B cell
help.
The macrophage, a pivotal cell in
many immunological functions, is
adversely affected by Zn deficiency,
which can dysregulate intracellular
killing, cytokine production, and
phagocytosis.
Zn deficiency affects the
development of acquired immunity by
regulating growth and function of T
and B cells.
Zn is needed for DNA replication,
RNA transcription, cell division, and
cell activation.
Apoptosis is potentiated by Zn
deficiency and Zn also functions
as an antioxidant and can
stabilize membranes.
Manganese
Component of several enzymes; requires bile for absorption
Deficiency: weight loss, transient dermatitis, n/v; changes in color, and slow growth of hair; sterility
Manganese toxicity
Miners
Accumulates in liver
Accumulates in CNS
Parkinson-like symptoms
Molybdenum
No deficiency has been described in humans or other
animals
Lead
Inorganic lead compounds have been known to be a toxic hazard
Chromium
Clear proof of the essentiality of chromium in humans has been difficult to attain
