thiamin, riboflavin, niacin

Question 1

what type of vitamins are thiamin, riboflavin and niacin (what letter)?

Answer 1

vitamin B (B1 B2 B3)

Question 2

what are the general functions of B vitamins

Answer 2

macronutrient metabolism
energy production
energy release
energy metabolism
transfer of single carbon units

Question 3

B vitamins are part of the structure of _____ that are needed for _____, which drive many reactions and pathways

Answer 3

co-enzymes

enzymes

Question 4

what are the 5 intermediary metabolism activities that vitamins are involved in?

Answer 4

CHO
-glycolysis and gluconeogenesis

PRO
-protein synthesis and AA oxidation

FATS
-FA synthesis and beta oxidation

ATP GENERATION
-respiratory chain and oxidative phosphorylation

NUCLEIC ACIDS/FA/STEROIDS
-pentose phosphate pathway

Question 5

what is Vit B1

Answer 5

thiamin

Question 6

what needs to happen to thiamine in order for it to act as a coenzyme

Answer 6

it needs to have two phosphates added to it

Question 7

study reminder

Answer 7

know structure of thiamine

Question 8

what is the co-enzyme form of thiamin

Answer 8

thiamin pyrophosphate (TPP)

Question 9

what are the metabolic roles of thiamin

Answer 9

• facilitiates energy release from foods
• central role in CHO metabolism
• oidative decarboxylation
  
  • -> pyruvate dehydrogenase
    - -> alpha-ketogluterate dehydrogenase
• transketolase reactions
  
  • -> also req. Mg

Question 10

CHO PRO and FAT all oxidize to ______, which is central in macronutrient metabolism

Answer 10

acetyl CoA

Question 11

what deficiency is associated with BERI-BERI (“ I cant I cant”)

Answer 11

thiamin (B1) deficiency

Question 12

what are general symptoms of thiamin deficiency

Answer 12

• dec fluid intake
• anorexia with weight loss
• neurological symptoms
• paralysis
• cardiovascular and respiratory

Question 13

can a thiamin deficiency be easily reversed

Answer 13

yes, with thiamin

Question 14

what was done to flour in canada that has made thiamin deficiencies rare?

Answer 14

fortification of flour

Question 15

what are the 3 types of BERI-BERI

Answer 15

WET (edema)
DRY (no edema)
INFANTILE

Question 16

what are symptoms of WET BERI-BERI

Answer 16

• cardiovascular, respiratory
• heart swelling
• pulmonary congestion

Question 17

what are symptoms of DRY BERI-BERI

Answer 17

• CNS impairment
• alcoholics (Wernicke-Korsakoff Syndrome)
• confusion, memory loss, confabulation (clear memory of something that never happened)

Question 18

what are signs of INFANTILE BERI-BERI

Answer 18

• brest fed infants of deficient mothers (or formula that doesnt have thiamin)
• vomiting, diarrhea, convulsions
• aphonia–crying but no sound coming out
• sudden death
• responds to thiamin quickly

Question 19

what is the EFSA

Answer 19

European Food Safety Authority

panel on dietetic products, nutrition and allergies

Question 20

which vitamin contributes to normal CHO and energy-yielding metabolism, and maintenance of normal neurological function

Answer 20

thiamin

Question 21

what is Vit B2, and why is it called B2

Answer 21

riboflavin

it was the second one that was discovered

Question 22

what are the coenzyme forms of riboflavin

Answer 22

FMN (flavin mononucleotide)

FAD (flavin adenine dinucleotide)

Question 23

is riboflavin water or lipid soluble

Answer 23

water soluble

Question 24

what are two characteristics of the appearance of riboflavin

Answer 24

yellow

fluorescent

Question 25

what vitamin needs riboflavin to function? | why is it needed

Answer 25

Vit B6 | riboflavin is essential for conversion of B6 to its co-enzyme form

Question 26

metabolic roles of FMN and FAD

Answer 26

-accept and donate hydrogens - part of flavin-dependent enzymes - called AA oxidases - respiratory chain/energy production - TCA cycle

Question 27

food sources for riboflavin

Answer 27

milk and milk products -photolabile... need to keep out of light liver, meat milling of wheat results in significant losses fortified flour in canada

Question 28

riboflavin deficiency

Answer 28

never fatal lesion symptoms - cheilosis (lesions around mouth) - magenta tongue - angular stomatitis - seborrheic dermatitis also affects vit B6

Question 29

what is the nutrient nutrient interaction between riboflavin and iron? *good exam question

Answer 29

riboflavin deficiency can impair mobilization of iron from its storage protein (ferritin) and impair iron absorption

Question 30

what are the two chemical structures of niacin (B3) ? which one is the major form in the blood?

Answer 30

nicotinic acid nicotinamide (major form in blood)

Question 31

what are the co-enzyme forms of niacin

Answer 31

NAD (H) (nicotinamide adenine dinucleotide) NADP (H)

Question 32

what AA can niacin be synthesized from?

Answer 32

tryptophan...an essential AA!

Question 33

what is the conversion of tryptophan to niacin?

Answer 33

60mg tryptophan = 1mg niacin

Question 34

what is the units used for niacin

Answer 34

niacin equicalents (NE)

Question 35

what do we have to take into consideration when calculating niacin intake?

Answer 35

protein intake

Question 36

what is the beginning and end result in the Kynurenin Pathway?

Answer 36

tryptophan---->niacin (co enzyme forms; NAD/NADP

Question 37

what two vitamins does the Kynurenine pathway need

Answer 37

riboflavin Vit B6

Question 38

we can replace the need for niacin in the diet of rodents, dogs and pigs, by putting _____ in the diet

Answer 38

tryptophan

Question 39

why is it called the kynurenine pathway

Answer 39

because kynurenine is a key intermediate in the conversion of tryptophan to niacin (in its coenzyme form)

Question 40

niacin transfers _____ during metabolic reaction what types of reactions are these

Answer 40

hydrogen oxidation/reduction

Question 41

study reminder

Answer 41

``` review how and where niacin is used in: Glycolysis/gluconeogenesis TCA cycle ETC pentose phosphate pathway ```

Question 42

during oxidation, Niacin acts as a hydrogen (acceptor/donor)

Answer 42

acceptor NAD(P) --> NAD(P)H

Question 43

during reduction, niacin acts as a hydrogen (acceptor/donor).

Answer 43

donor NAD(P)H becomes NAD(P)

Question 44

pentose phosphate pathway is an alternative route of ______metabolim

Answer 44

glucose

Question 45

what are the 2 purposes or the pentose phosphate pathway

Answer 45

generate NADPH, then used for syntehsis of FA and steroids generate ribose for synthesis of nucleic acids

Question 46

what are the four D's? (symptoms)

Answer 46

diarrhea dermatitis dementia death

Question 47

Niacin deficiency

Answer 47

- pellagra (rough skin) | - four D's

Question 48

study reminder

Answer 48

go over pellagra case study

Question 49

what is hartnup's disease

Answer 49

autosomal recessive disorder | -development of pellagra due to defect in absorption process for tryptophan

Question 50

Niacin and the plague of corn | what is corn limiting in?

Answer 50

niacin is bound and unavailbe limiting in tryptophan this leads to pelllagra

Question 51

what is the solution to the plague of corn

Answer 51

alkali treatment; | breaks the bond and makes niacin available

Question 52

what nutrients would impact niacin status

Answer 52

protein riboflavin Vit B6

Question 53

what nutrient has been used as a cholesterol lowering agent?

Answer 53

nicotinic acid

Question 54

Niacin and CVD

Answer 54

unique among lipid-lowering drugs like statins as it has been shown to not only reduce LDL-cholesterol but also increase HDL-cholesterol and decrease lipoprotein (a) levels

Question 55

what are some side effects of niacin treatment?

Answer 55

abdominal pain, rash, liver toxicity