Micronutrients

Question 1

B1

Answer 1

H2O soluble

Found in most foods

Absorbed in ileum/ jejunum

Question 2

B2

Answer 2

H2O soluble

Found in most foods

Absorbed in small intestine

Question 3

B12

Answer 3

H2O soluble

Found in animals sources

Absorbed in distal ileum

Question 4

C

Answer 4

H2O soluble

Found in plants

Question 5

D

Answer 5

Fat soluble

D2 found in animal sources

D3 found in sun light

Absorbed in half the small intestine

Question 6

Iron

Answer 6

Inorganic

Found in plant and animal sources

Absorbed in proximal small intestine

Question 7

Calcium

Answer 7

Inorganic

Found in plants and vegetables

20-30% absorbed in stomach

Absorbed with vit D in duodenum

Question 8

Vitamin D mechanism

Answer 8

Passive diffusion into intestinal mucosa

D2/3 converted into 25 hydroxy vit D in the liver

25 hydroxy vit D converted to active 12 dihydroxy vit D in the kidneys

Question 9

B12 mechanism

Answer 9

HCl breaks down bond with protein and it then binds to R factor

Released from R factor and binds to IF in jejunum

In presence of Ca2+, B12 and IF bind to specific factors

Absorbed into blood vessels in distal ileum

Question 10

Vitamin A mechanism

Answer 10

Proteins: in the stomach are hydrolysed by pepsin and in upper SI by proteolytic enzymes

Carotenes: made into micelles, absorbed into membrane, converted to retinal

Question 11

B2 mechanism

Answer 11

Proteolytic enzymes release from bound proteins

Brush border enzymes hydrolyses then its absorbed

Question 12

Vitamin C mechanism

Answer 12

Passive diffusion in through buccal membrane using carrier

At high concentration >100mml around 6% is absorbed

Question 13

B1 mechanism

Answer 13

When low its absorbed with Na+ for transport

Above 8mg its absorbed passively