Consequences of Malnutrition

Question 1

In which type of vitamin is overdose more likely: lipid-soluble, or water-soluble?

Answer 1

Lipid-soluble

Question 2

Which type of vitamin needs to be replenished constantly: lipid-soluble, or water-soluble?

Answer 2

Water-soluble

Question 3

Are vitamin and mineral deficiencies a big problem in Australia?

Answer 3

Low level problem but could be contributing to chronic disease

Question 4

Why do vitamin and mineral deficiencies occur?

Answer 4

Modern Western diet can be poorly balanced/not variable enough
Individual diet may miss specific sources
Crops can lack nutrients because of availability in soil
Other disorders/lifestyles can interfere with absorption

Question 5

In whom are vitamin and mineral deficiencies of concern?

Answer 5

Pregnant women
Young children
Elderly people

Question 6

What does production of vitamin D need?

Answer 6

Exposure of skin to UV or dietary intake

Question 7

In what foods is vitamin D found?

Answer 7

Fatty fish
Oysters
Eggs
Fortified margarine

Question 8

Where does vitamin D act as a hormone?

Answer 8

Intestines
Kidneys
Bones

Question 9

What are the roles of vitamin D?

Answer 9

Bone-making and maintenance by maintaining blood concentrations of Ca and P

• Enhances absorption from GIT
• Enhances re-absorption from kidneys
• Mobilises from bone into blood

Question 10

How is vitamin D produced?

Answer 10

7-dehydrocholesterol > 2 steps in skin (using UV) > cholecalciferol (vitamin D3) > 1 step in liver/kidney > calcitriol

Question 11

Is vitamin D3 active?

Answer 11

No

Question 12

Is calcitriol active?

Answer 12

Yes

Question 13

What happens in severe vitamin D deficiency in children?

Answer 13

Rickets

• Failure of normal calcification of bones
• Growth retardation
• Skeletal abnormalities
  
  • Bent long bones of leg

Question 14

Who are at higher risk of vitamin D deficiency?

Answer 14

Dark skinned people living very north/south
Fair skinned people who avoid sun exposure
Night shift workers, office workers, taxi drivers
Older people - skin, liver, and kidneys lose capacity to activate vitamin D
Older/disabled people who’re housebound/in care
People covered for religious reasons

Question 15

Wat happens in vitamin D deficiency in adults?

Answer 15

Loss of Ca from bones > fractures

Question 16

What is the role of calcium in the bones?

Answer 16

99% of body’s Ca in bones and teeth
Essential component of bone structure for rigid frame
Ca bank for blood levels Ca

Question 17

What is the role of calcium in the blood?

Answer 17

1% in blood and cells
Part of many enzymes
Mediates hormonal responses
Essential for blood coagulation
Used in muscle contraction
Needed for neuromuscular function

Question 18

Who are at risk of rising blood calcium?

Answer 18

Breastfeeding babies whose intake of milk high

Question 19

How are falling blood calcium levels elevated?

Answer 19

1. Parathyroid hormone stimulates activation of vitamin D
2. Vitamin D and parathyroid hormone stimulate Ca reabsorption in kidneys
3. Vitamin D enhances Ca absorption in intestines
4. Vitamin D and parathyroid hormone stimulate osteoclasts > break down bone > release Ca into blood

Question 20

What do blood levels of calcium indicate?

Answer 20

Nothing - they’re always stable

Question 21

How do you measure levels of calcium in bone?

Answer 21

No measures

Can measure bone mass and density

Question 22

What foods in Australia are fortified?

Answer 22

Thiamine in bread
Folate and iodine in flour
Breakfast cereals voluntarily commonly fortified

Question 23

What proportion of Australian women over 19 don’t have an adequate intake of folate?

Answer 23

9%

Question 24

Who are recommended to take extra folate?

Answer 24

All women of childbearing age

Question 25

What does a folate deficiency in pregnancy cause?

Answer 25

Neural tube development defects; eg: spina bifida

Question 26

What cellular processes need folate?

Answer 26

``` DNA - Replication - Repair - Methylation Especially relevant during rapid cell division and development ```

Question 27

Why is it important to have adequate amounts of folate before you find out you're pregnant?

Answer 27

Neural tube development complete by 4 weeks | Very rare for woman to know she's pregnant at this time > don't often know until 6-8 weeks

Question 28

What does folate deficiency in adults cause?

Answer 28

Macrocytic/megablastic anaemia | Characterised by large RBCs

Question 29

Why does macrocytic anaemia occur in folate deficiency?

Answer 29

Slow repair of DNA damage

Question 30

Is macrocytic anaemia because of folate deficiency common?

Answer 30

No, but some anticancer drugs can interfere with folate levels > deficiency

Question 31

How is macrocytic anaemia treated?

Answer 31

Extra folate

Question 32

What is the relationship between folate and vitamin B12?

Answer 32

Need each other for activation

Question 33

What is vitamin B12 needed for?

Answer 33

Regenerated levels of methionine | DNA and RNA synthesis

Question 34

Why do vitamin B12 levels decrease slowly?

Answer 34

Recycled for re-use

Question 35

Where is vitamin B12 found?

Answer 35

Only in animal products | Almost all of vitamin B12 in plants inactive > vegans at risk of deficiency

Question 36

How is folate activated?

Answer 36

Folate in food as polyglutamate = inactive In intestine - breaks off glutamates > adds methyl groups > absorbed and delivered to cells = inactive In cells trapped in inactive form Vitamin B12 removes and keeps methyl group - Removal of methyl activates folate - Addition of methyl activates vitamin B12

Question 37

How does a vitamin B12 deficiency lead to damage to myelin sheaths of peripheral nerves?

Answer 37

Levels of metabolic intermediates like methylmalonine CoA build up Cause damage to myelin sheath

Question 38

What are the symptoms of vitamin B12 deficiency?

Answer 38

Reduced performance on tests of intelligence and short-term memory Creeping paralysis starting in extremities

Question 39

What are the symptoms of an inability to activate folate?

Answer 39

Megablastic anaemia | - Often 1st symptom of vitamin B12 deficiency

Question 40

What would be the effect of treating megablastic anaemia of a patient with vitamin B12 deficiency with folate?

Answer 40

Rapidly fix anaemia Still have vitamin B12 deficiency Peripheral nerve damage continues

Question 41

What is the number one cause of preventable intellectual disability in children?

Answer 41

Iodine deficiency

Question 42

What does a major iodine deficiency cause?

Answer 42

Goitre

Question 43

Why may have mild iodine deficiency recently re-emerged in Australia?

Answer 43

Lower salt diet

Question 44

Are difficulties in school caused by a mild iodine deficiency reversible with iodine supplementation?

Answer 44

Yes

Question 45

What does severe iodine deficiency during pregnancy cause?

Answer 45

Severe and irreversible physical and mental retardation = cretinism

Question 46

What is the most common deficiency in the world?

Answer 46

Fe

Question 47

What is iron a part of?

Answer 47

Haemoglobin and myoglobin P450 enzymes Lysosomal enzymes Ribonucleotide reductase

Question 48

Why is iron never found free in the body?

Answer 48

Extremely toxic

Question 49

How is iron kept in the body?

Answer 49

Bound to transport/storage proteins

Question 50

From where is iron recycled in the body?

Answer 50

RBCs

Question 51

How are iron stores depleted?

Answer 51

Shedding of intestinal and skin cells | Blood loss through menstruation in women

Question 52

Why do children need more iron?

Answer 52

To increase blood volume

Question 53

What is thiamine used for in the body?

Answer 53

Essential part of coenzyme thiamine pyrophosphate

Question 54

What does severe thiamine deficiency cause?

Answer 54

Beriberi - Oedema - Muscle wasting

Question 55

Is thiamine deficiency common in Australia?

Answer 55

No, rare | Except when caused by alcoholism

Question 56

What are the dietary risks associated with alcoholism?

Answer 56

Low intake Impaired absorption Alterations in storage Possibly increased excretion

Question 57

How can absorption be impaired in alcoholism?

Answer 57

Damage to cells lining intestine Alterations in function of pancreas > reduced digestive enzyme production Alterations in fat absorption limits intake of lipid soluble vitamins - A - E - D

Question 58

How can storage be altered in alcoholism?

Answer 58

Decreased liver function > decreased vitamin A store

Question 59

What vitamins and minerals are vegans at risk of being deficient in?

Answer 59

``` Vitamin B12 Vitamin D Fe Ca Zn ```

Question 60

Why are calcium and vitamin D important in the elderly?

Answer 60

Vital for preventing loss of Ca from bones > reducing risk of fractures

Question 61

Why may the elderly develop deficiencies?

Answer 61

``` Harder to shop for fresh foods Harder to cook Could be cooking for just 1 Tastes and appetites change Dental problems/dentures can make chewing harder Changes in digestion and absorption through - Age - Disease - Medication ```