Iron deficiency and Folate/Vitamin b12 deficiency Flashcards
1
Q
Define hypochromic.
A
Low in colour red cells
2
Q
Define microcystic.
A
Small, low hemoglobin
3
Q
How are the red blood cells in iron deficiency?
A
Hypochromic and microcystic
4
Q
How are the red blood cells in folate or vitamin B12 deficiency?
A
Megaloblastic or pernicious anemia
5
Q
Name examples of structures made from amino acids but are NOT a protein.*
A
Heme
6
Q
Iron functions
A
- Transfer oxygen
- As part of a Heme group in the protein to transfer oxygen around the body
- Myoglobin in muscles for oxygen storage
- Transport of electrons in the electric transport chain( cytochromes)
- Many enzymes like peroxidase,myeloperoxidase,catalse
7
Q
Where is hemoglobin is made?
A
In the bone narrow
8
Q
Why too much iron is not a good thing?
A
Because it can increase lipid peroxidation and other reactions that can cause damage to our body
9
Q
How many oxygens on hemoglobin and myoglobin
A
Hemoglobin-4
Myoglobin-1
10
Q
What is interesting about the structure of the hemoglobin molecule?
A
It does not have nucleus and other organelles to maximize the space for oxygen
11
Q
What happens to the cells with iron deficiency?
A
Alteration of DNA sythesize->hypochromic microcytic anemia
12
Q
What is pika?
A
A term to describe a craving to chew substances that have no nutritional value(ice,clay,soil,paper). A sigh of severe iron deficiency
13
Q
Signs and symptoms of iron deficiency
A
- Tiredness
- Lower work performance
- Problems with memory, mental capacity and decline in intellect in children
- Higher lead poising susceptibility( as there will be no competition for absorption)
14
Q
What level of hemoglobin in blood should be to diagnose as anemic?
A
Men -<140g/L
Women -<120 g/L
15
Q
Compare the prevalence of iron deficiency in developed vs. developing countries.
A
Developing: 50% women + children, 25% men Developed: 7-12% women + children
16
Q
What percentage of low income infants in Montreal have iron deficiency?
A
25%
17
Q
How many people worldwide have iron deficiency anemia?
A
4-5 billion people
18
Q
What should iron metabolism be if an individual is healthy?
A
Iron intake = Iron losses
19
Q
Describe free iron.
A
Toxic (oxidative stress)
20
Q
What happens to the iron when it gets into our body?
A
- Mucosal cells in the intestine store excess iron in mucosal ferritin
- Of the body does not need it, it will be excreted with mucosal cells in 3-5 days
- If needed , will be given to transferrin that travels around the body
21
Q
Where are the primer storage for iron?
A
Liver,bone marrow,spleen
22
Q
What will be done in the body, if there is not enough Fe?
A
Increased in transferrin sythesize+ transferrin will have more binding sites->maximize the space available for iron binding and transport
- Less ferritin sythesize
- Increase efficiency of absorption and release from IEC (intestinal epithelial cells)
23
Q
Transferrin delivers iron to
A
Bone marrow and other tissues
24
Q
Iron stored in the form of
A
Ferritin -plasma,IEC and hemosiderin-liver
25
What is hepcidin?
Regulating hormone,that keeps in balance between ferritin and transferrin
26
Describe the recycle circuit of iron in the body
Liver and spleen dismantles RBC, packages iron into transferrin and stores excess iron in ferritin and hemosiderin
27
How much transferrin is occupied by iron usually?
1/3
28
What does different saturation of transeferrin mean?
-Low saturation indicates deficiency of iron
| High saturation indicates over-supply of iron
29
What happens to trasnferrin receptors in iron rich environment
Decrease
30
How much is the number of the total body iron?
2.5 to 3.8 grams
31
1 micrograma ferrtin/L is equal to how much storage of iron
10 mg
32
What are the total iron loses for men and women?
Men -1 mg
| Women -1.4 mg
33
How iron can be lost?
- Gi losses( Gi blood, Gi mucosal,bile)
- Desquamented skin cells and sweat
- Urinary losses
- Menstrual losses
34
Where iron is incorporated into hemoglobin?
Bone marrow
35
How long do circulating RBCs live?
120 days
36
In what state does iron function in?
2+ state
37
Why does vitamin C help iron absorption?
It is a reducing agent: Fe3+ to Fe2+ = more absorbed
38
Describe the pathway of iron in the body
Ferritin->transferrin->Bone marrow+protoporphyrn(a precursor for hemoglobin)->heme->hemoglobin->RBCs->Liver->Bilirubin or Iron back to transferrin
39
At what stages iron can be measured?
Transferrin level+how iron binds to it
- Hemoglobin levels
- RBCs and their size
- Bilirubin in the urea or in the blood
40
What is bilirubin?
A yellow compound that occurs in the normal catabolic pathway that breaks down heme . Used in bile synthesize and also excreted in urine
41
Deficiency or excess of iron over time leads to
Malnutrition
42
Symptoms of malnutrition with iron
-Diarrhea
Skin rashes
Fatigue
Others
43
Define the 4 components of iron balance.
1) Iron intake (dietary iron + bioavailability) 2) Amount of iron in storage 3) Rate of erythrocyte production 4) Iron losses
44
What should we know for a total picture of the individual for iron deficiency?
- Historical information ( like health status, social economic status,drug use, diet history)
- Anthropometric measurements
- Physical examination (hair,skin,eyes,tongue,finger nails)
- Laboratory tests
45
What happens to the tongue and to the nails during iron deficiency?
Tongue-change of color
Pale skin
Spoon finger nails
46
How can you assess primary deficiency
Diet history
47
How can you assess secondary deficiency
Health history
48
How can you assess declining nutrient stores
Laboratory tests
49
How do you measure abnormal functions inside the body
Laboratory tests
50
Physical signs and symptoms
Physical examination and anthropometric measure
51
What is the first step in developing iron deficiency ?
Depletion of iron stores->decline in serum ferritin in the IEC, liver and spleen
52
What is the second step in developing iron deficiency?
- Increased absorption deficiency
- Increased transferrin iron binding capacity
- Decreased transferrin saturation %( more receptors, but less binding )
- Increased transferrin receptors
53
What happens at the third stage of developing iron deficiency ?
Defective erythropoiesis(red cell production)
Decreased plasma iron
Decreased Erythrocyte protoporphyrin
54
When iron deficiency is considered as anemia?
At the last 4th stage , when there is microcytic hypochromic erythrocytes and associated behavioral signs (fatigue,etc.)
55
Causes of iron deficiency
```
Decreased dietary iron
Less iron absorbed( Ca, fibre)
Vegetarian diets lack heme
2.Inhibition of absorption
Mineral Interactions: Calcium, zinc supplements can iron absorption
Absorption inhibitors
3.Increased red cell mass
Pregnancy, growth
4.Increased losses
Hemolysis (rupturing of RBC)
GI bleeding (occult)
Heavy menstrual losses
```
56
What are the most iron rich foods
Broccoli,Tomato juice,Clams,beef liver,parsley
57
Two types of iron of food, where it can be found and bio-availability
Heme( meat sources) and non-heme( vegetables)
In meat 40% is heme iron, 60% is non-heme
Vegetables have only non-heme iron
Heme is 25% absorbed
Non-heme is 17% absorbed
58
Non-heme iron is increased by
Vitamin C,sugars,acids including AA
59
Non-heme iron is decreased by
Ca, P, phytates(grains, legumes, nuts),oxalates(spinach),polyphenols ( beans, nuts), tannins( tea),EDTA(preservative)
60
Why chilli with beans is better than just beans for iron
Because heme iron helps the absorption of non-heme iron
61
What is the iron situation in Canada
Men are fine
| Women are struggling to get the iron( only 25 % are meeting the requirement)
62
RDA for normal men and premenopausal women
Men-8 mg/d
| Women -18 mg/day
63
RDA for men and women who are vegan
M-14 mg
| Women -33 mg
64
RDA for women woth oral contraceptives and pregnancy
OCs- 11 mg
| Pregnancy -27 mg
65
UL for iron
45 mg/day
66
Treatment for iron deficiency
-Diet
supplement
•ferrous sulphate or gluconate
retest
67
Iron deficiency prevention
Fortify food supply
68
Iron overload and toxicity
Acute iron toxicity or poisoning, especially kids
Iron overload from repeated transfusions: Hemosideros->cirrhosis
Megadoses of Vitamin C –Pro-oxidant
can reduce ferric iron bound to transferrin to free ferrous iron
free iron is a powerful oxidant: Fenton reaction
69
What is Hemochromatosis
Autosomal recessive, most common geneticdisorder in US (1.5 million people)
More common in men than iron deficiency
Very efficient iron absorption due to defective hepcidin production (hormone that inhibits iron release from IECs)
TX: phlebotomy, desferroxamine, low iron diet, low vitamin C
70
What is the name of vitamin B12 and its structure
Cobalamin-B-12
| Large molecule with cobalt in the middle
71
B 12 absorption
Released from proteins by HCl+pepsin, absorbed in the small intestine with the help of intrinsic factor
72
Name 2 functions of folate and vitamin B 12
- DNA synthesis and repair - Plays important role in cell division and growth
73
What is the correlation between folate and vitamin B12
They need each other for activation
74
What is one individual role for vitamin B12?
Protect nerve fibers and bone cell activity
75
Why vitamin B12 is needed in small amounts and the danger connected with it
It can reabsorbed and it takes 3 years to develop the deficiency, but it is very crucial for pregnant women and her baby
76
Food sources of vitamin B12
Animal sources. Best availability in fish and milk
77
How should vegan get vitamin B 12
Fortified plant beverages and cereals , B 12 fortified nutritional yeast( only a specific species grown in vitamin B 12 rich environment)
78
Symptoms of vitamin B 12 and folate deficiency
Fatigue, dementia,peripheral nerve degeneration
79
What is folate?
Vitamin B9
80
Name some sources of folate.
• Leafy green vegetables • Fresh, uncooked vegetables & fruits • Eggs • Orange juice & legumes
81
In foods, how does folate naturally occur?
Polyglutamate (multiple glutamates)
82
What is the chemical structure of folate?
3 rings and a glutamate
83
In enriched foods and supplements, how does folate naturally occur?
Monoglutamate Absorbed 2x as efficienctly
84
Explain B 12 and folate metabolism
Folate with multiple glutamates-> in the intestine folate monoglutamate+methyl group( inactive form)-> to be activated, B 12 takes methyl to itsself. Now both folic acid and B 12 are activated
85
What happens with B 12 and homocysteine?
B12 converts homocysteine in methionine. Low folate and B 12 -> high homocesteine-> high oxidative stress
86
What can stop folate from being recycled?
Folate cannot be recycled unless b12 takes it out of its trapped inactive form
87
How do red blood cells during folate OR vitamin B12 deficiency?
- DNA strands break and cell division diminishes - RNA synthesis continues, resulting in a large cell and large nucleus - Megaloblastic anemia: large, immature, nucleated cells
88
Why does megaloblastic B12 and folate anemia look the same?
Since the methyl group transfer is the issue
89
What is the difference between megaloblastic anemia and pernicious anemia
Megaloblastic anemia-> primary deficiency (lack of dietary folate and B12)
Pernicious Anemia->secondary deficiency ( intrinsic factor deficiency, low acidity in the stomach)
90
How megaloblastic and pernicious anemias are cured?
Megaloblastic anemia - quiet rare, slow to develop, only if inadequate intake
Pernicious Anemia-given injections or nasal spray of vitamin B 12
91
How can folate affect birth defects? What is the neural tube?
Neural tube will not develop properly with low folate The neural tube is the embryonic tissue that forms the brain and the spinal cord
92
Three neural tube defects diseases
Spina bifida( gap or split int he spinal cord)
Anecephaly( partial or complete absence of brain)
Encephalocoele (brain and skull are malformed)
93
Why are all pregnancies at risk for neural tube defects?
95% of pregnancies with it have no previous histories
94
Name 3 risk factors for folate deficiency during pregnancy.
1) Diet-Preconceptional Folate status 2) Genetic Link (family history with NTD on either side) 3) Ethnic Background (northern European and Hungarian ancestry)
95
What did Health Canada suggest pregnant women do to avoid NTD? What did they opt for instead?
Multivitamin contain 0.4 mg of folate to take starting BEFORE pregnant = unrealistic - Fortify food supply instead
96
Name 3 reasons why you would fortify the food supply.
1) To correct or prevent widespread nutrient deficiency 2) To restore nutrients lost in processing 3) To add nutrients normally supplied in the food the product replaces (soy beverage)
97
Name 2 fortification controversies.
• Targeting the at-risk population • Optimal intake (fix problem without endangering others)
98
How can folate supplements mask B12 deficiency?
- Additional folate will erase megaloblastic anemia - Does not fix neurological problem of B12 deficiency - High intake of folate, don’t need to bother recycling folate WE JUST USE NEW FOLATE, then we have healthy looking RBCs, we don’t know whether it is fresh folate all the time or if it is because we recycled it
99
What is the link between Alzheimer's and folate intake?
Characterized by brain atrophy associated with low plasma folate - Highest levels of folate show lowest cognitive decline
100
High levels of folate decreases the risk of what?
Stroke and depression
101
What is associated to lower levels of vitamins B6, B12 and folate?
High homocysteine
102
What are high levels of homocysteine a risk factor for?
Independent risk factor for heart diseases (atherosclerosis, formation of blood clots)
103
How does vitamin deficiency cause high levels of homocysteine?
Causes a bottleneck of homocysteine removal, build up and the homocysteine damages arteries Vitamin B12 and folate are implicated in the synthesis of methionine from homocysteine, if there is less of these nutrients, there will be more homocysteine and less methionine
104
Folate in food
Lentils, Asparagus,brocolli, tomato juice
105
Fortification with iron pros and cons
-prevent anemia( if the grains are fortified with iron , need to take vitamin C to maximize the effect
-But the toxicity for men with hemochromatosis( need to choose not fortified food without vitamin C)
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