Sites of absorption of vitamins

What are the specific sites of absorption of vitamins? I know vitamin k is absorbed in the large intestine and B12 in the ileum and that's about it.

Reply 1

Mariaa_bxx

2

Original post by Tmkz

What are the specific sites of absorption of vitamins? I know vitamin k is absorbed in the large intestine and B12 in the ileum and that's about it.

Have you got the OCR 2017 papers?

Reply 2

macpatgh-Sheldon

20

Hi,

Sorry you have not had a relevant reply yet - let me try to help.

You are correct that B12 is absorbed across the ileal mucosa - this process requires a protein, called intrinsic factor, secreted by the gastric parietal cells. Deficiency of intrinsic factor leads to pernicious anaemia [a type of macrocytic anaemia [with large erythrocytes]].

The fat soluble vitamins (A, D, E and K) are absorbed with fats as micelles after conversion to esters. Any disease that reduces bile secretion or blocks the bile duct reduces their absorption [bile is needed for emulsification of fats].

Vitamins B1 (thiamine), B2 (riboflavine), niacin, B6 (pyridoxine) and ascorbic acid (vitamin C) are sodium-dependent as they are absorbed by Na+ cotransporters (mostly in the duodenum). Vitamin B12 and folate absorption do not require sodium.

Thanks,
M

Reply 3

Tmkz

OP

6

Original post by Mariaa_bxx

Have you got the OCR 2017 papers?

Nope and I can't see them on the ocr website, have you seen a question like this in that paper?

Reply 4

Tmkz

OP

6

Original post by macpatelgh

Hi,

Sorry you have not had a relevant reply yet - let me try to help.

You are correct that B12 is absorbed across the ileal mucosa - this process requires a protein, called intrinsic factor, secreted by the gastric parietal cells. Deficiency of intrinsic factor leads to pernicious anaemia [a type of macrocytic anaemia [with large erythrocytes]].

The fat soluble vitamins (A, D, E and K) are absorbed with fats as micelles after conversion to esters. Any disease that reduces bile secretion or blocks the bile duct reduces their absorption [bile is needed for emulsification of fats].

Vitamins B1 (thiamine), B2 (riboflavine), niacin, B6 (pyridoxine) and ascorbic acid (vitamin C) are sodium-dependent as they are absorbed by Na+ cotransporters (mostly in the duodenum). Vitamin B12 and folate absorption do not require sodium.

Thanks,
M

Thank you very much! This was very useful :smile:

Reply 5

Tmkz

OP

6

Original post by macpatelgh

Hi,

Sorry you have not had a relevant reply yet - let me try to help.

You are correct that B12 is absorbed across the ileal mucosa - this process requires a protein, called intrinsic factor, secreted by the gastric parietal cells. Deficiency of intrinsic factor leads to pernicious anaemia [a type of macrocytic anaemia [with large erythrocytes]].

The fat soluble vitamins (A, D, E and K) are absorbed with fats as micelles after conversion to esters. Any disease that reduces bile secretion or blocks the bile duct reduces their absorption [bile is needed for emulsification of fats].

Vitamins B1 (thiamine), B2 (riboflavine), niacin, B6 (pyridoxine) and ascorbic acid (vitamin C) are sodium-dependent as they are absorbed by Na+ cotransporters (mostly in the duodenum). Vitamin B12 and folate absorption do not require sodium.

Thanks,
M

Btw did u use any sources or is this just from memory? Just so that I can do some further reading myself