micronutrients

Question 1

what are micronutrients?

Answer 1

vitamins and tracelements

Question 2

what are the roles of micronutrients?

Answer 2

cofactors
coenzymes
antioxidants
genetic control
structure

Question 3

what are cofactors? give an example

Answer 3

non-protein chemical compound or metallic ion required for a protein’s biological activity to happen. E.g. iron/zinc

Question 4

what are coenzymes? give an example

Answer 4

Small non-protein organic molecule. Cannot by themselves catalyze a reaction but they help enzymes to do so. E.g. thiamine pyrophosphate (TPP

Question 5

what are antioxidants? give an example

Answer 5

inhibits the oxidation of other molecules. E.g. beta-carotene/vitamin C

Question 6

give examples of micronutrients involved in genetic control?

Answer 6

vitamins A and D

Question 7

how are micronutrients involved in structure? give examples

Answer 7

Phospholipids form complexes with both Mg” and Ca”. These complexes are integral parts of the various membranes in the cell

Question 8

why are micronutrients needed in children?

Answer 8

needed for energy supply and body growth and development

Question 9

what does the recommended dietary allowance define?

Answer 9

how many micronutrients we need

limits for deficiency and toxicity

Question 10

how do fat-soluble vitamins enter the portal circulation?

Answer 10

micelle –> chylomicron to get into the intestinal lining –> portal circulation

Question 11

how do water soluble vitamins enter the portal circulation?

Answer 11

directly through the intestinal lining

Question 12

give examples of fat soluble vitamins?

Answer 12

A D E K

Question 13

give examples of water soluble vitamins?

Answer 13

B, folate, biotin, C

Question 14

can fat soluble vitamins be stored?

Answer 14

yes

Question 15

can water soluble vitamins be stored?

Answer 15

no

Question 16

what happens to excess fat soluble vitamins?

Answer 16

become toxic

Question 17

what happens to excess water soluble vitamins?

Answer 17

excreted in the urine

Question 18

what are the causes of vitamin deficiency in developed countries?

Answer 18

decreased intake of vitamins
decreased absorption
others - renal disease or drug antagonists

Question 19

what can cause a decreased intake of vitamins?

Answer 19

alcohol dependency - lack of vitB1
small bowel disease - B9
vegans - vitD and B12
elderly w poor diet - D
anorexia - folate

Question 20

what can cause decreased absorption of vitamins?

Answer 20

ileal disease - only B12
liver and biliary tract disease - fat soluble vitamins
intestinal bacteria overgrowth - B12
oral antibiotics - K

Question 21

what is the clinical feature and contributing factor to deficiency in vitamin A

Answer 21

Infection, measles, protein-energy malnutrition

Xerophthalmia

Question 22

what is the clinical feature and contributing factor to deficiency in vitamin D

Answer 22

Aging, lack of sunlight

Rickets, oestomalacia

Question 23

what is the clinical feature and contributing factor to deficiency in vitamin E

Answer 23

Antibiotic use

peripheral neuropathy

Question 24

what is the clinical feature and contributing factor to deficiency in vitamin K

Answer 24

antibiotic use

coagulpathy

Question 25

what is the clinical feature and contributing factor to deficiency in vitamin C

Answer 25

smoking scurvy

Question 26

what is the clinical feature and contributing factor to deficiency in vitamin B1

Answer 26

Concommittant Vitamin B6, B12 & folate deficiency beri beri

Question 27

what is the clinical feature and contributing factor to deficiency in vitamin B2

Answer 27

malabsorption Magenta tongue, angular stomatitis

Question 28

what is the clinical feature and contributing factor to deficiency in vitamin B3

Answer 28

Vitamin B6 deficiency, riboflavin deficiency pellagra

Question 29

what is the clinical feature and contributing factor to deficiency in vitamin B6

Answer 29

Isoniazid use anaemia

Question 30

what is the clinical feature and contributing factor to deficiency in vitamin B12

Answer 30

Gastric atrophy (pernicious anemia), terminal ileal disease, strict vegetarianism anaemia

Question 31

what is the clinical feature and contributing factor to deficiency in folate

Answer 31

Sulfasalazine, pyrimethamine, triamterene anaemia

Question 32

what is kwashiorkor disease?

Answer 32

a severe form of malnutrition caused by lack of dietary protein

Question 33

what is marasmus?

Answer 33

a severe form of malnutrition that occurs in children. causes muscle wasting/protein loss

Question 34

why is nutrition important?

Answer 34

Impaired wound healing and immune response Reduced muscle strength Inactivity leads to pressure sores and thromboembolism Increased risk of postoperative complications Depression and self-neglect

Question 35

what does iron deficiency lead to?

Answer 35

anaemia, lethargy and constitutional disturbance microcytic anaemia, lethargy and fatigue, cognitive impairment in children

Question 36

what is iron needed for?

Answer 36

oxygen transport in haemoglobin and myoglobin function in skeletal muscle

Question 37

where is iron absorbed?

Answer 37

upper small bowel

Question 38

how and where is iron stored?

Answer 38

stored in liver and bone marrow as ferritin

Question 39

what does iron excess lead to?

Answer 39

haemochromatosis, lethargy and fatigue, abdominal and joint pain, reduced libido, bronzing of skin, diabetes, cirrhosis

Question 40

what lifestyle factors contribute to vitamin D deficiency?

Answer 40

obesity, smoking, alcohol and exercise

Question 41

what disease factors contribute to vitamin D deficiency?

Answer 41

reduced skin synthesis, decreased bioavailability, drug-related, increased excretion, acquired (e.g. TB)

Question 42

what does rickets lead to?

Answer 42

growth retardation and the expansion of the growth plate

Question 43

what is osteomalacia?

Answer 43

reduced bone strength

Question 44

what does osteomalacia lead to?

Answer 44

increase in bone fracture, bone pain, bending of bones, muscle weakness and waddling gait

Question 45

what does thiamine deficiency lead to?

Answer 45

Wernicke’s Encephalopathy and Korsakoffs Psychosis

Question 46

what is thiamine?

Answer 46

vitamin B1

Question 47

where is thiamine absorbed?

Answer 47

jejunum

Question 48

what is thiamine used for?

Answer 48

glycolysis, Krebs cycle, BCAA metabolism, pentose phosphate cycle metabolism

Question 49

which vitamin is niacin and where is it absorbed?

Answer 49

B3 | jejunum

Question 50

what is niacin a generic name for?

Answer 50

nicotinic acid and nicotinamide

Question 51

what can cause niacin deficiency?

Answer 51

Vegetarian diet o Hartnup’s disease - Congenital defects of intestinal and kidney absorption of tryptophan o Carcinoid syndrome - Increased conversion of tryptophan to Serotonin o Isoniazid use - TB treatment

Question 52

what are early symptoms of pellagra?

Answer 52

loss of appetite, generalised weakness, irritability, abdominal pain, vomiting and bright-red glossitis

Question 53

what are late symptoms of pellagra?

Answer 53

Casal’s necklace, vaginitis, oesophagitis, diarrhoea, depression and seizures

Question 54

what is Casal's necklace?

Answer 54

skin rash particularly in areas exposed to sunlight

Question 55

what are the 4 Ds of pellagra?

Answer 55

dermatitis, diarrhoea, dementia , death

Question 56

what does folate deficiency cause in foetuses?

Answer 56

neural tube defects

Question 57

what can cause a B12 deficiency?

Answer 57

``` Inadequate intake: vegans Disorders of terminal ileum Defective release of cobalamin from food Inadequate production of IF Transcobalamin II deficiency (rare) Congenital enzyme defects (rare) ```