Micronutrients and Trace Elements Flashcards
1
Q
function of iron
A
- oxygen transport in blood/ muscle
- electron transport
2
Q
function of iodine
A
thyroxine (T4)
triiodothyronine (T3)
ability of thyroid gland to concentrate iodine
3
Q
function of zinc
A
- gene expression
- zinc metalloenzymes
- cell membrane structure/ fxn
- induce metallothionein synthesis
4
Q
function of copper
A
oxidative enzymes
5
Q
function of selenium
A
- important antioxidant
- glutathione peroxidase
- thyroid function ( interaction with I)
6
Q
function of molybdenum
A
xanthine oxidase
sulfite oxidase
7
Q
function of manganese
A
- mitochondrial SOD
- CHO metabolism
- mucopolysaccharide synthesis
8
Q
function of chromium
A
-facilitates binding of insulin to receptors
9
Q
function of fluoride
A
integrity of teeth/ skeleton
10
Q
function of cobalt
A
structure of cobalamin b12
11
Q
heart failure, anorexia, slow growth
A
severe iron deficiency
12
Q
anemia, impaired cognitive development, decreased exercise tolerance
A
mild iron deficiency
13
Q
hypothyroidism
A
severe iodide deficiency
14
Q
goiter
A
mild iodide deficiency
15
Q
spontaneous abortion, cretinism, deafness, mental retardation
A
fetus iodide deficiency
16
Q
acro-orficial dermatitis, diarrhea, increased infections, poor wound healing, delayed sexual maturations, personality changes
A
severe zinc deficiencies
17
Q
growth retardation, anorexia, increased infections
A
mild zinc deficiency
18
Q
intra-uterine growth retardation, congenital malformations
A
fetus zinc deficiency
19
Q
mental retardation, seizures, connective tissue defects, fractures
A
severe copper deficiency
20
Q
anemia, neutropenia, osteoporosis, seborrheic skin lesions
A
mild copper deficiency
21
Q
connective tissue defects baby
A
fetus copper deficiency
22
Q
cardiomyopathy, skeletal myopathy
A
severe selenium deficiency
23
Q
macrocytosis, loss of hair pigment, hypothyroidism
A
mild selenium deficiency
24
Q
sources of iron
A
Heme Iron:
-Cellular animal protein
Non-heme Iron:
-legumes, nuts, whole grains
25
Iron Absorption:
Dietary Factors:
insoluble complexes
phytate, tanins
26
Iron Absorption:
| Oxidation state
- ascorbic acid: Fe3+ --> Fe2+
| - absorption enhanced for reduced state
27
Iron Absorption:
| Mineral Mineral Interactions
-excessive Zn or Cu decreases Fe absorption
28
Iron Absorption:
| Host Factors 2
1. Fe deficiency --> increased absorption
| 2. inflammation--> increased hepcidin from liver --> decreased absorption at enterocyte
29
Iron Absorption:
| Quantity in Gut lumen
inverse relationship
30
main site of iron regulation
intestinal absorption
31
major route of iron loss
bleeding
32
major iron stores
liver, bone marrow, spleen
33
Iron transport and storage form
transport: transferrin
Storage: ferritin/ hemosiderin
34
most common nutritional deficiency in the world
iron
35
iron deficiency in men or post-menopausal women
merits investigation for source of bleeding
36
iron deficiency manifestation
- Anemia: microcytic, hypochromic
| - W.o anemia: impaired cognitive function, growth
37
iron deficiency diagnosis
Severe Deficiency:
-low Hb/Hct & microcytic/ hypo chromic rbc
Mild, moderate/ Severe Defic:
-low ferritin
Low % Sat:
-low serum Fe with high TIBC
38
labs to check with ferritin
- ferritin is an acute phase protein elevated with inflammation
- need to also check ESR or CRP for accurate interpretation
39
Iron is a potent pro-
oxidant
40
large doses of supplemental iron interfere with absorption of
zinc and copper
41
hereditary hemochromatosis
- defect in hepcidin
- excessive Fe absorption
- accumulated Fe damages liver and increases risk of HCC
42
medicinal FE overdose
-hemorrhagic gastroenteritis
-shock and acidosis
coag defects
-hepatic failure
43
lethal Fe dose in children
1-2grams
44
especially critical during periods of growth and cellular/ tissue proliferation & immune function
zinc
45
sources of zinc
```
animal products (oysters)
beef> poultry> fish/milk/ eggs
```
46
zinc absorption is impaired by
phytate, a dietary complex involved in iron absorption
found only in plants,~corn, legumes, nuts
47
Zinc Absorption:
| Systemic levels
unlike iron absorption, since absorption is not increased with deficiency
48
zinc homeostasis maintained by what paired processes
absorption and excretion
- zinc secreted into go tract with digestion as part of pancreatic-biliary secretions
- some is reabsorbed and some is excreted
49
how is zinc homeostasis different from iron
there is a route to excrete zinc, whereas with iron the body has to be careful how much iron to take in because it can be toxic and is difficult to get rid of
50
7 populations at risk for iron deficiency
- infants > 6 mths: low stores & high requirement
- premature infants: low stores & high requirement
- adolescents: high requirement & poor intake
- pregnant women: increased requirement (27mg/day)
- chronic infestations
- bariatric surgery
- elderly
51
9 populations at risk for zinc deficiency
- infants
- young children
- breastfed infants >6mths
- pregnant women
- monotonous plant diets: esp high in phytate
- bariatric surgery
- elderly
- GI illness/ injury: diarrhea
- Wounds, burns
52
why are breastfed infants > 6mths at risk for zinc deficiency?
after 6mths because human milk has low Zn levels after 6mths
53
contrast risk populations iron (2) deficiency vs zinc deficiency (4)
Iron:
- adolescents
- Chronic infestations
Zinc:
- breastfed infants >6mths
- monotonous plant diets: esp high in phyla
- Diarrhea
- Wounds/ burns
54
poor zinc status in the elderly is associated with a higher risk of what?
pneuonia
55
Copper ot zinc ratio (CuZ)
increased ratio in the elderly associated with higher mortality, may be a biomarker of aging
56
Zinc deficiency and death
worldwide
-estimated to account for 0.4 million deaths/ year in children younger than 5
(second only to vitamin A which is estimated to be responsible for 0.6 million deaths/ year)
57
acrodermatitis enteropathica
- mutation in zinc transporter ZIP4
- fatal if not treated
- responds to high doses of Zn supplements (lifetime)
58
acrodermatitis enteropathica presentation
severe dermatitis, growth failure, diarrhea
59
zinc toxicity
- relatively low
| - >50mg/d can decrease HDL, impair absorption of Fe and Cu, cause nausea, diarrhea
60
zinc within first 24hours of symptoms of a cold
- decrease duration of illness by 1-4 days
- reduce severity of symptoms
- may prevent viral replication or attachment to nasal membranes
61
iodine sources
- seafood
- grown things: depends on content of soil- especially low in mountainous areas
- Today: iodized salt
62
cassava
- goitrogen
- contains ions that compete with iodide (like SCN-)
- associated with widespread goiter and hypothyroidism
63
Absorption process iodine
Iodide Uptake --> binding to T3, T4 --> Circulation
64
iodine worldwide deficiency
common--> endemic goiter and cretinism in children (5.7 million cretins exist; 1 billion persons at risk for I deficiency disorders)
65
Cretin child: deaf mutism
- dwarfed, mentally retarded, dull facies, large tongue
| - I deficiency during pregnancy
66
I deficiency on fetus
-increased abortions, stillbirths, congenital abnormalities
67
goiter
-enlarged thyroid gland to compensate for decreased I for thyroid hormone synthesis
68
populations with endemic iodine deficiency
mean IQ loss: 13.5 points
69
Copper food source
shellfish, meats, nuts
| low in milk
70
Copper absorption and metabolism
30-40% absorption from mixed diet, stored in liver, excreted in bile
71
Selenium
foods associated with with amino acids
72
keshan disease
-cardiomyopathy in china prevented with Se supplementation
Cause:
-interaction with other nutritional deficits or viral infection
*Viral mutation increases virulence in Se deficient host
73
selenium absorption and metabolism
- 60-80% absorbed from diet
- Kidneys main site of homeostasis
- urine excretion
