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Flashcards in Minerals Deck (110):
1

Define bioavailability

The degree to which the amount of an ingested mineral is absorbed and available to the body

2

What are factors altering mineral bioavailability?(4)

Deficiency of minerals
Chemical binding of mineral to other elements of diet
Excess of mineral
Presence of vitamins

3

Examples of mineral bioavailability altering (5)

Reduced storage will increase absorption of minerals from GI tract/kidney
Phytates in plants bind to minerals preventing absorption
Excess zinc decreases iron and copper absorption
Vitamin C presence increase zinc absorption
Vitamin D presence increases calcium absorption

4

Which minerals maintain osmotic pressure?(3)

Sodium
Chloride
Potassium

5

Minerals involved in skeletal structure (3)

Magnesium
Phosphorus
Calcium

6

Minerals involved in acid base equilibrium (pH) (3)

Phosphorus
Calcium
Magnesium

7

What is a metalloprotein?

Protein bound to metal

8

Examples of metalloproteins (3)

Haemoglobin
Myoglobin
Cytochromes

9

Major role of metalloenzymes

Regulate biological processes within the body

10

Examples of metalloenzymes (4)

Glutathione peroxidase
Carbonic anhydrase
Pyruvate carboxylase
Cerulolasmin ferroxidase

11

What can cause mineral deficiencies?(2)

Inadequate diet
Inability to digest mineral

12

Define metabolic deficiencies

Inability of the body to digest minerals from sites in the body or from diet

13

What is the major source of sodium in foods?

Sodium chloride

14

What are the roles of sodium (4)

Nerve conduction
Nutrient absorption and transport
Maintenance of membrane potential
Regulation of osmotic and electrolyte balance

15

What is the primary regulator of water intake

Thirst

16

Regulation of fluid and electrolyte balance (11)

Decreased blood pressure/blood volume
Kidneys release renin into circulation
Stimulates angiotensin 1 then angiotensin 2
Causes vasoconstriction

Angiotensin 2 also causes aldosterone to be synthesised by adrenal glands
Kidneys increase reabsorption of sodium
Increases water retention
Increases blood volume
Increases blood pressure

Low BP/BV increased ADH production from pituitary gland
Stimulates kidneys to increase water reabsorption
Increase BP

17

What is hypnotremia?

Decreases sodium concentration in blood plasma

18

What causes hyponaetremia?(3)

Excessive hypotonic sweating
Prolonged vomiting or diarrhoea
Diuretics

19

What is hypernatremia?

Increased sodium concentration in blood plasma

20

What causes hypernatremia?(3)

Excess fluid loss
Inadequate water intake
Renal failure causing excess sodium

21

Effects of excess sodium chloride?(5)

Hypertension
Edema
Stomach cancer
Osteoporosis - excess calcium excretion
Left ventricle hypertrophy

22

What is the average amount of iron in human body?(5)

2-4g

65% Haemoglobin
10% myoglobin
1-5% enzymes
Rest in blood and storage

23

Which oxidation states does iron exist in the human body?(2)

Fe2+ - ferrous, haem
Fe3+ ferric, non-haem

24

Which type of foods contains some heam iron?(3)

Meat, poultry and fish (also has non haem, veggies + fruit exclusively have non haem)

25

Roles of iron (4)

Oxygen transport
Cofactor for enzymes
Energy production
Pro-oxidant

26

How much of body weight is accounted for by minerals

4%

27

Examples of specific roles of iron (4)

Cofactor for enzymes - succinate dehydrogenase in TCA cycle
Pro-oxidation - lipid peroxidation
Energy production - cytochrome contains haem which transports election through ETC
Oxygen transport - control to Haemoglobin structure

28

Iron absorption (7)

Dietary non-haem (Fe3+) is reduced to Fe2+ for transport across the apical brush border
Uses divalent metal transport 1 (DMT1)
Dietary haem iron is transported across border by Haem Carrier Protein 1
Haem is released from a bigger dietary haem structure by haem oxygenase
Some iron stored in ferritin
Ferroportin exports some iron for it to be incorporated into serum transferrin

29

What is a mineral?(3)

Building blocks of rocks
Inorganic nutrients
Present in the soil, rocks and water

30

Describe ferritin (3)

Iron storage protein found in all cells
Stores ferric iron (Fe3+)
Amount of ferritin directly reflects amount of iron in body

31

Describe transferrin (3)

Glycoprotein synthesised in the liver
Ferric iron is transported in blood bound to transferrin
Delivers iron to site of storage or utilisation

32

What increases haem absorption (2)

Low iron status
Low haem iron intake

33

What increases non haem absorption (5)

Depleted iron status
Pregnancy
Vitamin C (ascorbic acid)
Meat, Fish, seafood
Anaemia

34

What decreases haem absorption (3)

High iron status
High haem iron intake
Calcium

35

What decreases non haem absorption (5)

Replete iron status
Low gastric acid
Phytates
Iron-binding phenolic compounds
Calcium

36

3 stages of iron deficiency

Depletion of strange iron - decreases in serum ferritin
Decrease in transport iron
Decrease in iron for Haemoglobin for new blood cells

37

Effects of iron deficiency (4)

Fatigue
Anaemia
Poor cognitive development in babies
Babies born with poor motor skills

38

Where is iodine found?(3)

Rocks
Seawater
Some soils

39

Good sources of iodine (2)

Seaweed
Seafish

40

Iodine absorption (3)

Rapidly absorbed in the gut
Distributed throughout whole body
Excess excreted in urine

41

On average how much iodine is present in humans

20-30 mg

42

Roles of iodine (7)

Thyroid hormone synthesis in thyroid gland

Thyroid hormones regulates:
metabolic rate
Thermogenesis
Growth and development
Blood cell production
Nerve and muscle function
Modulates gene expression by binding to receptors

43

Iodine deficiency (3)

Many people affected worldwide
Causes goitre - swelling in neck
Can cause mental retardation - lower IQ points

44

What is goitre (3)

Enlargement of thyroid glands
Causes by iodine deficiency - under 50 mg per day
Reversible with iodine treatment

45

What is cretinism (4)

Due to iodine deficiency prior to birth
Neurological syndrome - mental retardation
Stunts growth
Irreversible

46

What can affect iodine bioavailability

Goitrogens

47

How do goitrogens affect bioavailability (4)

Reduce iodine metabolism by reducing iodine uptake
Reduce synthesis of thyroid hormone
Reduce release of hormone from gland

May compete with iodide for uptake by thyroid gland

48

Examples of goitrogens (2)

Thiocyanates
Cyanogenic glycosides

49

What causes iodine toxicity

Over 2g a day over a prolonged time

50

Selenium food sources (5)

Seafoods
Organ meats
Cereals and grains
Dairies
Brazil nuts

51

Which selenium source is more bioavailable

Plant sources

52

Differences in absorption of organic and inorganic selenium (4)

Organic - actively transported, more rapidly absorbed
Inorganic - passively absorbed, slower absorption

53

Which proteins are selenium typically bound to in the blood (2)

VLDL
Albumin

54

Food sources of calcium (3)

Dairies
Sardines with bones
Fortified products

55

Factors that improve calcium absorption (3)

Vitamin D
Lactose containing foods ingested at the same time
Sugar alcohols

56

Factors that inhibit calcium absorption (8)

Fibre
Phytates
Oxalates - found in spinach and squash
High sodium
High protein
High caffeine
Soda - phosphoric acid
Tannin - in tea

57

Roles of calcium (5)

Bones and teeth
Neuronal transmission
Blood clotting
Muscle contraction/relaxation
Cofactor for enzymes

58

Food sources of phosphorus

Same foods as calcium

59

How does vitamin D regulate low calcium and phosphorus availability in the blood (3)

Stimulate increased absorption from GI tract
Increase retention at kidney
Withdrawal from bones to blood (resorption)

60

How does PTH regulate calcium (4)

Increase bone resorption
Increase kidney reabsorption
Increase PO4 excretion
Increase calcium absorption from small intestine by synthesising calcitrol from kidney

61

What is 1,25(OH)2D and its roles (5)

Metabolite of vitamin D produced in kidney increase blood calcium by promoting absorption of dietary calcium from GI tract
Increases calcium reabsorption
Increases release of calcium from bone

62

Inadequate dietary calcium consequences (3)

Maintain blood calcium at expense of bones
Osteoporosis - low BMD
Osreomalcia - rickets in children

63

What are minerals classified by?(2)

Requirement
Tissue amount

64

What classes as a macro mineral (2)

Over 5g found in body
Over 100mg needed a day

65

What classes as a micro mineral (2)

Under 5g in body
1-100 mg needed a day

66

Trace mineral (2)

Trace amount found in body
Under 1mg needed a day

67

What happens if their a high levels of trace mineral in the body?(2)

Become chemically reactive
Becomes toxic

68

What is the most common mineral deficiency

Iron

69

What vary mineral requirements?(5)

Pregnancy
Lactation
Growth
Frequency activity
Gut parasites

70

What causes hidden hunger (4)

Poor food security
Geographical location
Food processing
Metabolic deficieny

71

How can geo location affect diet(2)

Soil content of mineral is variable
Problematic for those who are dependent on local food

72

Why must iron be bound to protein

Free iron is toxic

73

Examples of how food processing can lead to an improper diet (5)

For example increase salt content to make foods more palatable
Increased sodium results in increased secretion - loss of calcium

Food preparation can reduce minerals - peeling and boiling

Milling of grains to refine them

74

Mechanisms to prevent iron toxicity (3)

Storage - bound to ferritin
Recycle iron to make new blood cells
Regulate amount of iron that is absorbed

75

What greatly impacts selenium concentrations in food sources?

Selenium soil concentration - influences intake

76

What is selenium converted to after being absorbed (2)

Selenophosphate then selenocysteine

77

Selenium anti oxidant mechanism (5)

Vitamin E donates electron to stabilise free radical and protect cell membrane
Vitamin E becomes a radical
glutathione donates electron to vitamin E so it can be regenerated
This requires glutathione peroxidase which contain selenium
Glutathione is regenerated by vitamin C (absorbed acid)

78

Consequences of selenium deficiency (3)

Kashin-beck disease
Osteoarthropathy
Keshan disease

79

Selenium toxicity symptoms (3)

Skin lesions
Garlic breath
Brittle hair and nails

80

Calcium regulation when calcium is high (3)

High plasma calcium stimulates an increase in calcitonin from thyroid
Inhibits bone resorption and calcium reabsorption
This decreases plasma calcium

81

Calcium regulation when plasma levels are low (7)

Increase in PTH and vitamin D
Increases absorption, reabsorption, resorption and PO4 renal excretion
Thus increases plasma calcium levels

82

What are DRVs determined to achieve for minerals (2)

Maintain a given circulating level/ tissue concentration
Absence of signs of deficiency disease

83

What is the most abundant cation + and anion - in the body?

Sodium
Chloride

84

Variable sources of iodine (3)

Plants
Cereals
Dairies

85

What is iodine absorbed as?

Iodide

86

What percentage of iodide is in the thyroid gland?

80%

87

Metalloenzyme associated with iron and its function

Succinate dehydrogenase
TCA Cycle

88

Metalloenzyme associated with copper and its functions

Ceruloplasmin ferroxidase

Iron utilisation
Copper transport

89

Metalloenzyme associated with zinc and its function

Carbonic anhydrase

CO2 formation

90

Metalloenzyme associated with manganese and its function

Pyruvate carboxylase

Pyruvate metabolism (TCA cycle)

91

Example of macro minerals (6)

Calcium
Phosphorus
Sodium
Potassium
Chloride
Magnesium

92

Examples of micro minerals (6)

Iron
Zinc
Copper
Selenium
Iodine
Manganese

93

Cereals with medium iron bioavailability

Corn flour

94

Cereals with low iron bioavailability (3)

Maize
Wholemeal flour
Rice

95

Fruits with low iron bioavailability (2)

Apples
Bananas

96

Fruits with medium iron bioavailability

Pineapple

97

Fruits with high iron bioavailability (2)

Orange
Lemon

98

Vegetables with medium iron bioavailability (2)

Carrot
Potatoes

99

Vegetables with low iron bioavailability (2)

Soya
Legumes

100

Vegetables with high iron bioavailability (2)

Cabbage
Broccoli

101

Nuts have ______ iron bioavailability

Low

102

Animal products with low iron bioavailability (3)

Cheese
Cow milk
Eggs

103

Animal products with high iron bioavailability (4)

Meat
Fish
Poultry
Breast milk

104

Examples of ferrous (Fe2+) supplements (2)

Ferrous sulphate
Ferrous fumarate

105

Iodine toxicity symptoms (6)

Fever
Burning sensations
Vomiting
Diarrhoea
Nausea
Coma

106

Rich sources of selenium (2)

Organ meats
Seafoods

107

What percentage of selenium is absorbed in the small intestine?

50-80

108

In which tissues have the highest iodine concentrations?(3)

Thyroid glands
Saliva glands
Gastric glands

109

Food sources of thiocyanates (3)

Cabbage
Kale
Sprouts

110

Food source cyanogenic glycosides

Cassava