Vit B12 and folate

Question 1

How do humans acquire vitamin B12?

Answer 1

Through diet

Question 2

What foods contain vitamin B12?

Answer 2

Foods of animal origin

Question 3

What happens to vitamin B12 in the stomach?

Answer 3

Stomach parietal cells produce intrinsic factor (IF)

Vitamin B12 binds to it

Question 4

What happens to the IF-B12 complex in the small intestine?

Answer 4

IF-B12 complex binds to receptors on epithelial cells in ileum
Vitamin B12 is absorbed
IF is destroyed

Question 5

How does vitamin B12 travel in the blood?

Answer 5

Bound to plasma protein transcobalamin

Question 6

What could cause vitamin B12 deficiency?

Answer 6

Dietary deficiency of vit B12

IF deficiency

Ileum disease

Transcobalamin deficiency

Question 7

What could cause IF deficiency?

Answer 7

Perinicious anaemia

Gastrectomy

Question 8

What is perinicious anaemia?

Answer 8

Autoimmune conidition
damages gastric parital cells
reduced production of IF

Question 9

What foods contain folate?

Answer 9

Green leafy vegetables

Liver

Question 10

Where does folate absorption occur?

Answer 10

Duodenum

Jejunum

Question 11

What is folate from diet converted into in the body?

Answer 11

Methyl tetra hydro folate

Question 12

What can cause folate deficiency?

Answer 12

Dietary deficiency of folate

Increased use of folate

Duodenum and jejunum disease

Drugs

Question 13

What can cause an increased use of folate?

Answer 13

Pregnancy

Increased erythropoiesis

Severe skin disease e.g. psoriasis

Question 14

How can drugs cause folate deficiency?

Answer 14

Inhibit dihydrofolate reductase enzyme

this is the enzyme resonsible for producting methylTHF

Question 15

What is an example of a drug that inhibits dihydrofolate reductase enzyme?

Answer 15

Methotroxate

Question 16

What is vitamin B12 deficiency associated with?

Answer 16

Neurological disease - focal demyelination affecting spinal cord, peripheral nerves