Unit 2 - Vitamins/minerals & nutrition

Question 1

what are the essential components of diet?

Answer 1

carbohydrates
proteins
lipids
minerals
vitamins 
water

Question 2

give source and function of iron

Answer 2

source: red meat
function: synthesis of cytochromes/ haemoglobin/ aerobic respiration

Question 3

what is the effect of iron deficiency + overload?

Answer 3

deficiency: anaemia - cannot produce haemoglobin - low O2- tired/shortness of breath
overload: haemochromatosis - oxidative/ liver damage

Question 4

how is iron regulated?

Answer 4

bound to transferrin and regulated by hepcidin

-erythroid factors inhibit hepcidin - more iron recycling

Question 5

give sources and functions of calcium

Answer 5

sources: dairy
functions: bones/ teeth/ muscles/ blood clotting

Question 6

what is the effect of deficiency + overload of calcium?

Answer 6

deficiency: hypocalcaemia- tooth decay/ osteoporosis/ dry nails
overload: disordered activation of enzymes

Question 7

give sources and functions of magnesium - deficiency/overload conditions

Answer 7

sources: green leafy veg/ pumpkin seeds/ nuts
functions: co-factor in protein synthesis/ muscle relaxation/ PTH function
deficiency: muscle cramps
overload: diarrhoea

Question 8

give sources and functions of phosphorus and condition of deficiency

Answer 8

sources: red meats/ fish
functions: strong bones/ teeth
deficiency: rickets/ osteoporosis

Question 9

give sources, functions of iodine and condition of deficiency

Answer 9

sources: white fish/ shellfish
functions: synthesis of thyroid hormones
deficiency: enlargement of thyroid glands

Question 10

give sources, functions of zinc and condition of deficiency

Answer 10

sources: meat/ shellfish
functions: wound healing/ processing carbohydrates/ erythropoiesis
deficiency: hair loss/ poor wound healing/ diarrhoea

Question 11

give sources, functions of copper and condition of deficiency

Answer 11

sources: nuts/ shellfish
functions: erythropoiesis/ haemoglobin formation
deficiency: growth failure/ anaemia
(menkes disease)

Question 12

which vitamins are fat soluble and which are water soluble?

Answer 12

A, D, E, K - fat soluble

B&C - water soluble

Question 13

how are these vitamins absorbed in the body?

Answer 13

fat-soluble vitamins absorbed in the same way as lipids

water soluble vitamins use sodium dependent carriers

Question 14

which vitamin is the exception in terms of absorption?

Answer 14

vitamin B12 - cobalamin
= released due to low pH of gastric juice
- binds to haptocorrin which protects it in the stomach but is degraded in the duodenum
- free B12 binds with intrinsic factor - the B12: IF complex is recognised by cubulin = receptor in brush border membrane and is absorbed by enterocytes in the lower ileum
complex transported to basolateral membrane and binds to transcobalamin II bfore entering capillaries for further protection

Question 15

give the sources, functions and condition of deficiency of B12

Answer 15

sources: microbes - cheese, beer
functions: red blood cell formation
deficiency -anaemia which can compensated for by folic acid

Question 16

give the sources, functions and condition of deficiency of B9

Answer 16

B9 - folic acid

sources: broccoli, leafy green veg
functions: RNA/ DNA synthesis
deficiency: spinal bifida = neural tube defects/ folate deficiency anaemia

Question 17

give the sources, functions and condition of deficiency of B6

Answer 17

B6- pyridoxine

source: whole grains
functions: neurotransmitter synthesis
deficiency: neurological issues

Question 18

give the sources, function of B5

Answer 18

B5 - pantothenic acid
sources: all meats and veg
functions: essential part of co-enzyme A
deficiency only occurs with victims of starvation

Question 19

give the sources, functions and condition of deficiency of B3

Answer 19

B3 - niacin

sources: meat/ fish/ wheat flour
function: constituent of NAD/ NADP
deficiency: pellagra: dementia, diarrhoea and dermatitis
overload: liver damage

Question 20

give the sources, functions and condition of deficiency of B1

Answer 20

B1- thiamin

sources: breakfast cereals
function: co-enzyme TPP for link reaction
deficiency: beriberi disease

Question 21

give the sources, functions and condition of deficiency of vitamin C

Answer 21

ascorbic acid

sources: oranges
functions: collagen synthesis/ carnitine synthesis
deficiency: scurvy

Question 22

give the sources, functions and condition of deficiency of vitamin A

Answer 22

provitamin - carotenoids converted to retinol in small intestine`

sources: liver/ oily fish/ dairy - milk/ cheese/ eggs
functions: formation of epithelia/ mucous membranes/ rhodopsin
deficiency: blindness
excess: toxic

Question 23

how is vitamin D produced?

Answer 23

D3 from animals - produced using UV light -7-dehydrocholesterol converted into 25, hydroxycholecalciferol (by 25-hydroxylase in liver) and then kidneys converts to its active form 1,25-dihydroxycholecalciferol (using 1-hydroxylase)
D2 from plants

Question 24

what is the recommended intake of vitamin D if pregnant and breastfeeding?

Answer 24

10 micrograms per day

Question 25

what is vitamin D role in calcium homeostasis?

Answer 25

decrease in plasma calcium is detected then levels of PTH increase which increases kidney production of vitamin D which increases plasma levels of 1,25 vitamin D so increases intestinal calcium absorption to increase levels of plasm calcium

Question 26

how else does PTH affect calcium homeostasis?

Answer 26

causes increase in bone calcium resorption so calcium released into plasma

Question 27

give the sources and functions of vitamin E

Answer 27

source: nuts, seeds, oil
functions: antioxidant, electron transfer, protects cell membrane from free radicals

Question 28

what is the effect of deficiency + overload of Vitamin E?

Answer 28

deficiency: muscle weakness, weak nerve impulses
overload: blurry vision

Question 29

give the sources and functions of vitamin K?

Answer 29

source: green leafy veg
functions: synthesis of prothrombin - haemostasis
+ clotting factors 2, 7, 9, 10