folate and b12

Question 1

food sources of folate

Answer 1

leafy green vegetables
legumes
orange
beef liver
rice

Question 2

natural folate found in food are __ and undergo irreversible __ during food prep and cooking

Answer 2

natural folate found in food are chemically labile and undergo irreversible oxidative degradation during food prep and cooking

Question 3

main folate transporter

Answer 3

PCFT

Question 4

folic acid uses __ transporter

Answer 4

folic transporter
unknown otherwise

Question 5

folate exits enterocyte via __ and enters __ blood

Answer 5

folate exits enterocyte via MDP and enters portal blood

Question 6

absorption of folate-derived molecules

Answer 6

1. poly-glutamate folate –> mono-glutamate folate
2. PCFT pulls mono-glutamate folate into enterocyte
3. mono-glutamate folate to methyl-THF
4. MDP on basolateral side pushes methyl-THF into portal blood

Question 7

food source of vitamin B12

Answer 7

animal foods, NO PLANT FOODS

Question 8

intestinal absorption of B12

Answer 8

1. intrinsic factor secreted by parietal cells in stomach bind B12
2. IF-B12 enters cell via B12 receptor
3. B12 in intesinal lumen (ileum) goes through enterocyte, into blood

Question 9

2 types of vit B12 transporters

Answer 9

1. transcobalamin II (TC-II)
2. Haptocorrins (TCI+III)

Question 10

TC-II

Answer 10

high affinity, low capacity
transports 30% of B12
specific receptors in most cells
function: cellular uptake of B12

Question 11

Haptocorrins (TCI+III)

Answer 11

low affinity, high capacity, transports 80-90% of B12
non-specific receptors in hepatocytes
function: circulating storage of B12

Question 12

B12 is mainly stored as

Answer 12

methylcobalamin

Question 13

where is most B12 stored?

Answer 13

liver

Question 14

normal B12 body stores can last you?

Answer 14

3-5 years

Question 15

more meat =

Answer 15

more B12