Lecture 1 - Introduction to Nutrition

Question 1

what does energy expenditure depend on

Answer 1

BMR (age, weight and sex) and amount of intensity of physical activity

Question 2

macronutrients

Answer 2

used immediately
excess carbs and fats stored
fat main stores of energy (80-90%)
protein can be metabolised for energy - not stored

Question 3

protein requirement of man

Answer 3

0.75 g/kg/day 75 kg man - 50 g

Question 4

what is nitrogen balance like in a healthy adult

Answer 4

nitrogen intake = excretion

Question 5

when is there negative and positive nitrogen balance?

Answer 5

negative - fasting: breaking down proteins for energy

positive: growth: body builds new tissue

Question 6

what AA’s do plants lack?

Answer 6

cysteine, methionine and tryptophan

Question 7

what are cholesterols and fatty acids precursors for

Answer 7

hormones and prostaglandins

Question 8

saturated fats

Answer 8

no double bonds

Question 9

mono-saturated

Answer 9

one double bond - found in olive and peanut oil

Question 10

poyunsaturated

Answer 10

more than one double bond - corn and sunflower oil

Question 11

trans (hydrogenated)

Answer 11

trans double bonds - cakes biscuit, pastry

Question 12

what is an essential fatty acid

Answer 12

omega 3 and omega 6, linoleic acid

Question 13

whata are carbs

Answer 13

polysaccharides - mainly starch, dissacharides - sucrose , monosaccarides - glucose and fructose
non-starch polysaccharide

Question 14

what are the fat soluble vitamins

Answer 14

vitamin ADEK

Question 15

Role of thiamin (b1) and deficiency

Answer 15

cofactor in decarboxylation reactions - krebs

beri beri - muscle weakness, nerve damage

Question 16

Riboflavin (b2)

Answer 16

Constituent of cofactors - FAD

very rare in deficiency

Question 17

niacin (b3)

Answer 17

consituent of cofactors NADH

Pellagra - diarrhoea, depression, dermatitis

Question 18

biotin (b7)

Answer 18

prosthetic group act as carrier for co2

very rare def - keep away from raw egg

Question 19

pyridoxal phosphate B6)

Answer 19

Cofactor for enzymes in protein metabolism, haem synth, neurotransmitter synth, modulates steroid hormone action

irritability, depression and confusion
inflammation of tongue and mouth

Question 20

Folic acid (B9)

Answer 20

dna synthesis, neural tube defects - spina bifida, anencephaly, macrocytic anaemia

Question 21

Cobalamin (B12)

Answer 21

found in animal products
methionine synth, odd chain fatty metabolim

Macrocytic anaemia,
irreversible neurological damage.
Commonly caused by autoimmune disease preventing absorption

Question 22

vitamin c

Answer 22

collagen synth, antioxidant

scurvy - symptoms caused by weake collagen

Question 23

vitamin d

Answer 23

bone formation and maintenance - immune regulation, muscle function

rickets in children
osteomalacia in adults

Question 24

vitamin e

Answer 24

acts as antioxidant, main role is to prevent lipid oxidation in membranes
def found in people with difficulty absorbing fats - neuro problems

Question 25

vitamin k

Answer 25

cofactor for enzymes which activate blood clotting proteins.May also be involved in bone maintenance.

Question 26

recommended sodium

Answer 26

less than 6 g a day

Question 27

why may nutritional deficiencies arise?

Answer 27

inadequate intake
inadequate absorption - probs with fat soluble vitamins abs - cystic fibrosis, coeliac, crohns
pernicious anaemia

excess loss/increased requirement

iron deficiency anaemia - persistent blood loss

folic acid defi in pregnancy - additional requirements not met

Question 28

globally, what deficiencies are of most importance?

Answer 28

vitamin a, iodine and zinc

Question 29

vitamin b12 deficinecy

Answer 29

more in vegans - only source is animal sources
pernincious anaemia frequent in elderly
b12 absorption dependent on binding protein - intrinsic factor
if absent - autoimmune destruction of cells that synthesis it or B12 itself