Trace Elements Flashcards
What are trace elements?
Inorganic micronutrients considered essential when deficiency in their intake causes impairmemt of function
How is function restored and symptoms alleviated when these trace elements are deficient?
By supplying physiological amounts of the element
What trace elements have specific biochemical functions and symptoms of deficiency in humans?
Cupper Zinc Iron Fluoride Iodine Chromium Selenium
What is the most abundant trace element?
Iron (Fe)
What trace elements have no clear biochemical functions but are symptomatic when deficient?
Cobalt
Boron
What trace elements have a clear biochemical function but do not show symptoms in deficiency?
Manganese
Molybdenum
How are clinically critical trace elements studied primarily?
Via indirect measurement
Indirect measurement of iron
Hemoglobin/red blood cells appearance
Transferrin/ferritin binding/storage/transport proteins
Indirect measurement of iodine
Thyroid hormone
Indirect measurement of copper
Ceruloplasmin
Indirect measurement for zinc
RBC protoporphyrin
What percentage of dietary copper is absorbed?
50%
What are the functions of copper?
Needed in many enzyme reactions
Role in regulation of iron metabolism, formation of connective tissue, energy production within cells, and nervous system
Percentage of copper in liver
10%
Percentage of copper in muscle, kidney, heart, brain
70%
What protein carried copper?
Ceruloplasmin
This a-2 globulin protein made in the liver is a copper-containing enzyme that plays a role in the body’s iron metabolism.
Ceruloplasmin
What percentage of circulating copper is bound to ceruloplasmin?
~95%
Why are preemies deficient of copper?
Cu stores in liver increase till the third trimester.
What can cause cu deficiency in adults?
Malabsorption
Inborn error of cu absorption/metabolism
What disease is deficiency of cu?
Menke’s syndrome
What disease is cu overload?
Wilson’s disease
What can cause cu overload?
Inborn errors of cu metabolism
How is excess cu is usually discarded?
Excreted in bile to feces.
What organ damage is seen in cu overload?
Hepatolenticular degeneration.
What is Menke’s syndrome?
X-linked defect in intestinal absorption, transport and storage of cu
What is seen in MS?
Decreased cu in all compartments like hair, brain, blood, liver, kidney, skin, bone
What are the signs and symptoms in MS?
Low ATP, collagen, and melanin. From childhood; growth failure, mental impairment, vascular lesions, hair and skin changes.
What are the lab findings in MS?
Low tissue cu
Low serum free cu
Low ceruloplasmin
What is Wilson’s disease?
Genetic defect in gene coding for enzyme responsible for cu excretion in bile/feces
What is the pathology seen in WD?
Too much cu accumulated in the body
Cu deposition in liver, brain, cornea
Mental status changes(Parkinson/dementia-like)
What lab findings are seen in WD?
High tissue cu High free serum cu Low ceruloplasmin High AST and ALT Kayser/fleischer ring in the eyes
Name other reasons for cu overload?
Increased synthesis of ceruloplasmin (during inflammation or consumption of oral contraceptives)
Increased intake of cu water/food)
What is the antidote of cu overload?
Metal chelation agents (EDTA penicillamine, BAL)
Stomach pumping
In what products is chromium found?
In meats and whole grains
What are the functions of chromium?
Important in glucose and lipid metabolism
Role in cardiovascular diseases and lipid homeostasis
Potentiates insulin action, making it more efficient
How does chromium potentiate insulin’s action?
By increasing insulin receptors and enhancing its binding to cells, increasing insulin sensitivity.
Chromium is transported bound to what beta globulin protein?
Transferrin
What is seen in chromium deficiency?
Cardiovascular disease
Impaired lipid profile
Impaired glucose tolerance and insulin resistance in some
What is seen in chromium toxicity?
Respiratory tract irritation, cancer (lungs, nasal and sinus), dermatitis/ulcers
Hypoglycemia
Liver, kidney, nerve damage
How is chromium toxicity contracted?
Occupational exposure (steelmaking, electroplating, leather tanning)
Hip prostheses with Cr alloy
Supplementation
What is fluoride necessary for?
To support mineralization of bone and teeth
Small doses help in osteoporosis
How does fluoride form fluorapatite in tooth enamel?
Fluoride ions replace hydroxyl groups in hydroxyapatite causing less susceptibility to acidic decay
What are the signs in excessive intake of fluoride (fluorosis)
Mottle or pitted teeth
Possible skeletal changes and crippling calcification of ligaments
What signs are seen in fluoride deficiency?
Tooth decay/dental caries
Possibly osteoporotic bone
Where is Se present in the body?
All tissues
With which vitamin is Se associated?
Vitamin E
What are the functions of Se?
Antioxidant in protecting cells from free radicals
Thyroid gland function
What disease is deficiency in Selenium?
Keshan’s disease
What is Keshan’s disease?
It is selenium deficiency with mutated coxsackievirus that has resulted in endemic cardiomyopathy
What signs are seen in se deficiency?
Cellular damage, immune disorder, hypothyroidism
What signs are seen in se toxicity?
Garlic smelling breath, hair less, nail damage, nausea/vomiting, nerve damage
In what type of food is zinc present?
All protein-rich foods
Zn is bound to
Albumin and a-2 macroglobulin.
This is an essential trace element in many metalloproteins and transcription factors like DNA/RNA polymerase, alcohol dehydrogenase, alkaline phosphatase
Zinc
What are zinc fingers?
Important structures that interact with DNA in proteins to regulate gene expression
What is the role of zn fingers?
Protein synthesis, stabilization of nucleic acids and organelles
What are other functions of zinc?
In prostate gland for sperm function
Supplementation in sickle cell disease can improve lifespan of RBC and reduce vascular obstruction
What causes zinc deficiency?
Decreased nutritional intake
Pregnancy (increased fetal demand)
Chronic alcoholism
Gi disease
What are the signs in zinc deficiency?
Growth retardation, dermatitis, poor wound health, alopecia
What causes zinc toxicity?
Acidic drinks in a zinc-coated container
What are the signs of zinc toxicity?
Nausea, vomiting, diarrhea, anemia, impaired immune function.
This an autosomal recessive disorder in which there is defective gene of a zinc transporter protein in the gut resulting in zinc deficiency
Acrodermatitis enteropathica
What are the symptoms of AE?
Slow growth, hypogonadism, dermatological lesions, diarrhea.
Function of Manganese
Enzyme activator, growth, carb and lipid metabolism
This trace element’s only known function is its part in cobalamin/vitamin B12
Cobalt
