Vitamins - Water Soluble and Fat Soluble Flashcards Preview

Metabolism > Vitamins - Water Soluble and Fat Soluble > Flashcards

Flashcards in Vitamins - Water Soluble and Fat Soluble Deck (53):
1

What are vitamins?

Organic compounds with essential biochemical functions that are not made by the body

2

What are the water soluble vitamins?

thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), pantothenic acid, biotin, folate, cobalamin (B12), and vitamin C (ascorbic acid)

3

What are the fat soluble vitamins?

A, D, E, and K

4

Vitamin deficiencies are

rare in healthy individuals on well-balanced diets

5

Vitamin deficiencies are important to consider

for unusual diets, during growth, in disease, and in developing countries

6

Fat soluble vitamin digestion is compromised by

pancreatic insufficiency or bile blockage

7

Water soluble vitamins are taken up by

the intestine

8

Vitamin K has no RDI because

it is made by gut flora

9

PLP

pyridoxal phosphate (B6)

10

NAD

niacin (B3)

11

CoA

Pantothenic acid

12

FMN, FAD

riboflavin (B2)

13

THF

folate

14

Thiamin (B1) is critical for

decarboxylations; carbohydrate, protein, and fat metabolism; nerve function

15

Deficiency of thiamin (B1) causes

beriberi (polished rice); Wernicke-Korsakoff (alcoholics)

16

Sources of thiamin (B1) include

vegemite, wholemeal breads, fortified cereals

17

Thiamin (B1) is a component of which enzyme?

Pyruvate dehydrogenase

18

Why is thiamin (B1) critical to nerve function?

It links anaerobic and aerobic metabolism (on which nerves rely) by pyruvate dehydrogenase

19

What is the role of riboflavin (B2)?

electron carrier - flavin mononucleotide (FMN), flavin adenine dinucleotide (FAD); carb, protein, and fat metabolism

20

Sources of riboflavin (B2) include

vegemite, milk, cheese, fortified cereals

21

Deficiency of riboflavin (B2)

is rare, usually only seen in chronic alcoholics with other deficiencies

22

What is the role of niacin (B3)?

coenzyme; electron carrier (NADH, NADPH); carb, protein, and fat metabolism

23

Sources of niacin (B3)

Vegemite, wheat bran, fortified cereals

24

Niacin (B3) deficiency

seen in alcoholics; Pellagra (dermatitis, diarrhoea, dementia, death)

25

Sources of pyridoxine (B6)

Vegemite, nuts, bananas, fortified cereals

26

Role of pyridoxine (B6)

amino acid metabolism (transamination)

27

Deficiency of pyridoxine (B6)

rare; need varies with protein intake; linked to original contraceptive pill in 60s

28

What is the role of biotin?

carboxylation in proteins (eg Acetyl-coA carboxylase to produce Malonyl-CoA); glucose, fat, amino acid biosynthesis

29

Sources of biotin include

brewer's yeast, cooked egg yolk (raw has avidin, antagonist of biotin); soy beans

30

Deficiency of biotin

caused by avidin in raw eggs, results in scaly, shiny, dry skin

31

What is the role of folate?

critical in DNA synthesis

32

Sources of folate include

green vegetables, liver, fortified cereals

33

Deficiency of folate

occurs commonly in elderly and chronic alcoholics; causes spina bifida if in pregnancy; causes macrocytic anaemia and glossitis (pillae die on tongue)

34

RDI for folate is

400ug/day (previously 120ug/day)

35

Folate supplementation may be linked to

increased rates of cancer due to its role in DNA synthesis

36

What is the role of cobalamin (B12)?

coenzyme containing cobalt; folate metabolism in DNA synthesis; transalkylations in nerves and blood

37

Sources of cobalamin (B12)

Meat, egg yolks, cheese

38

Deficiency of cobalamin (B12)

common in vegans and IF deficiency (genetic or autoimmune); causes pernicious anaemia with yellowish skin and faint icterus of sclerae due to bilirubin, lightening of hair and irises; peripheral neuritis

39

Intrinsic factor

glycoprotein produced by parietal cells of stomach necessary for B12 absorption; genetic or autoimmine deficiencies tx with B12 injections

40

What is the role of vitamin C?

cofactor in collagen synthesis (proline hydroxylase adding -OHs to prolines on outside of collagen that allow it to H-bond and give it strength); neurotransmitter metabolism; iron absorption; antioxidant

41

Sources of vitamin C

citrus fruit, cabbage

42

Deficiency of vitamin C

scurvy

43

What is the role of vitamin A?

half of B-carotene; produces retinal (night vision) and retinol (epithelium growth in skin and eyes)

44

Sources of vitamin A

B-carotene (coloured vegetables)

45

Vitamin A deficiency

xeropthalmia (dry eye) caused by retinol deficiency can lead to blindness if not treated

46

What is the role of vitamin D?

Ca2+ regulation and bone development - facilitates uptake of Ca2+ in gut which prevents it being absorbed from bones; mediates protection against infection, cancer, and autoimmune disease

47

Sources of vitamin D include

derived from cholesterol and synthesized with UV light and hydroxylations in liver and kidney to form calcitriol (hormone)

48

Deficiency of vitamin D

rickets in children (knock knees and bow legs); osteomalacia in adults (Ca taken from bones if can't get it from gut)

49

Vitamin D status is assessed by measuring

25OH-D; <25nmol/L = deficiency

50

What is the role of vitamin E?

antioxidant in membranes to accept free radicals; linked to signalling in inflammation and cell division

51

Sources of vitamin E include

high levels in seed oils

52

What is the role of vitamin K?

important in blood clotting - essential for the gamma-glutamyl carboxylase that adds a carboxyl group to glutamic acid eresidues on II, VII, IX, and X to activate them

53

Vitamin K deficiency

inadequate clotting and haemorrhage