basic principles of nutrition and healthy eating

Question 1

digestion definition

Answer 1

the process by which foods are broken down into smaller molecules or nutrients

Question 2

absorption

Answer 2

the uptake of nutrients and how the body utilises these nutrients to perform a wide range of bodily functions

Question 3

Excretion

Answer 3

the means by which the body removes unwanted, unnecessary or harmful substances from the body once it has extracted what it needs

Question 4

the body’s two mechanisms for breaking down food consumed

Answer 4

mechanical

chemical

Question 5

mechanical digestion

Answer 5

chewing/mastication
also involves rolling of tongue to create small balls of mixed food = ‘bolus’
not limited to mouth - continues throughout digestive system using ‘peristalsis’
the smooth muscle tissue of the walls of digestive organs involuntarily contract to push foods along. cylindrical shape of digestive tract is optimal for this process.

Question 6

chemical digestion

Answer 6

how the body breaks down foods into simpler nutrients using enzymes
enzymes are protein molecules that accelerate specific chemical reactions
speed up rate of digestion - would be too slow to sustain life without them

Question 7

the digestive tract

Answer 7

also known as alimentary tract, alimentary canal, gastrointestinal tract
mouth to anus
transit time = time for food to pass through the tract
for healthy adult transit time 24-72 hours
av tract is 9meters long

Question 8

3 functions saliva

Answer 8

1) moistens food so tongue can form ‘bolus’
2) starts carbohydrate digestion - contains amylase which breaks it down into glucose
3) be present in food consumed

Question 9

pharynx

Answer 9

has both digestive and respiratory functions
forms passageway connecting the mouth and nose to oesophagus and larynx
3 diff muscles
primary structure for swallowing ~ a reflex ~ 1-3 seconds

Question 10

oesophagus

Answer 10

approx 10 inches in length
connects throat to stomach
runs parallel to trachea
protected by cartilage called ‘epiglottis’ ~ seals the trachea so food is transported to stomach and not lungs
with medium bolus take about 5-8 seconds for food to get to stomach

Question 11

stomach

Answer 11

J shaped
can expand 8 times the size
located just left to centre of chest - below sternum
3 layers of tissue
gastric juices with food creates chyme
hydrochloric acid kills invading bacteria - so corrosive that stomach lined with mucus to prevent digesting itself
pepsin - breaks down protein - can only work in vv acidic conditions
emptying of stomach takes 3-4 hours depending on food consumed, hydration and physical activity levels
moves onto small intestine
alcohol is only substance that is directly absorbed into stomach

Question 12

functions of pancreas

Answer 12

producing and releasing enzymes for digestion (trypsin, amylase, digest
creating and releasing blood regulating hormones (insulin and glucagon)
produces bicarbonate - neutralises acidity

Question 13

Gall Bladder and Bile Duct

Answer 13

below liver

gallbladder stores bile produced by liver and delivers to small intestine via bile ducts

Question 14

the liver

Answer 14

storage of carbs in form of glycogen 
hormone production 
blending and emulsification of fats 
excretion of old blood cells 
production of bile storage in the gall bladder
production of cholesterol 
filters and neutralises toxins
storage of some vitamins and iron

Question 15

small intestine

Answer 15

longest of intestinal tracts - 5-6 metres 
first section (10 inches) is the duodenum 
second section (3-4 metres) is the jejunum = most nutrient absorption takes place
final section (3-4 cm) is the ileum = remaining nutrients absorbed 
inside the small intestine are cilia - hair like structures that provide large surface area to increase rate of absorption - they have a rich blood supply 
food absorbed goes to liver which is good for nourishing it but bad when has to detoxify from substances like alcohol to prevent cellular damage. 
takes bout 3-4 hours for food to pass through SI - but varies according to different factors

Question 16

large intestine

Answer 16

1.5 metres
av time of waste matter to stay in colon is 36 hours 
reabsorbs water from waste matter
manufacturing of vitamins b and k 
excretion of waste

Question 17

what is a calorie

Answer 17

one calorie is the amount of energy it take to raise one gram of water by one degree

Question 18

metabolic rate

Answer 18

BMR does not take into account increased energy required to stay awake and therefore resting metabolic rate is more accurate for estimating a persons needs
BMR and RMR decreases with age because lean tissue decreases which reduces the amount of energy the body burns = body’s energy needs reduced
males higher metabolism - more testosterone = more lean muscle

Question 19

carbs

Answer 19

complex and simple
complex - essential for anyone regularly exercising = slow and sustained release of energy
simple - sugary = quick supply of energy ~ not sustainable - kept to minimum except for micronutrients

Question 20

free sugars

Answer 20

form of simple carb added to food or drink for flavour

also naturally present in honey, syrup and fruit juice

Question 21

glucose and glycogen

Answer 21

carbs are broken down into glucose and absorbed into bloodstream but if additional blood glucose is not required the glucose is stored in the liver and/or skeletal muscles as glycogen

Question 22

functions of carbs

Answer 22

body’s preferred source of energy
1g carbs = 4kcals
carbs are the only source the brain and nervous system can use as energy in form of blood glucose
higher levels of glycogen stores are linked with increased aerobic performance
help maintain a healthy metabolism by preventing the use of muscle protein for energy = muscle tissue sparing
carbs also needed for water storage
1g glycogen in muscles and liver is with 3g water
55-60%

Question 23

fibre

Answer 23

plant based carbs - not digested in small intestine
absorbs water - bulks out food
transports waste and good through gastrointestinal tract

Question 24

protein

Answer 24

animal products contain amino acids that plants do not so plant based people should insure they get a range
veg protein = incomplete
10-12%

Question 25

functions of protein

Answer 25

growth and repair of bodily tissues production of hormones and enzymes transports oxygen and regulates blood clotting used as energy source when there is insufficient carbs - this is undesirable as results in loss of learn tissue 1g protein = 4kcals

Question 26

fats

Answer 26

``` 1g fat = 9kcals saturated and unsaturated saturated - gen solid at room temp ~ animal and dairy sources. soft and low density substance that sticks to inside of blood vessels - can restrict transit of blood = increased blood pressure also heart strain unsaturated = gen liquids at room temp plant sources fat - 25-30% 15-20% from unsaturated ```

Question 27

functions of fat

Answer 27

can only be burned in presence of oxygen (aerobically) fats are essential for transporting vitamins a,d,e,k provides protection to vital organs controls body temperature manufacturing hormones

Question 28

cholesterol

Answer 28

soft waxy substance found among fats in the bloodstream and in body's cells used to form cell membranes, some hormones and a number of essential functions

Question 29

water

Answer 29

45-70% bodyweight cannot be used directly as source of energy but used in energy releasing and metabolic reactions rec 2-2.5litres depending - increased for exercise

Question 30

euhydration

Answer 30

state of optimal hydration

Question 31

functions of water

Answer 31

``` regulating body temperature reducing strain on cardiovascular and regulates blood pressure delivers nutrients in blood plasma elimination of waste from body lubrication of joints and tissues protection of foetus constipation relief ```

Question 32

micronutrients

Answer 32

``` help body release energy from food regulation of cell function building blocks for cells and organs healthy teeth and bones aid with muscle function/contraction vision transport oxygen in red blood cells regulate and maintain water balance ```

Question 33

vitamins

Answer 33

'organic compounds' no energy content can be broken down by heat, air or acid during metabolism body cannot manufacture vitamins so they have to be supplied in diet

Question 34

minerals

Answer 34

'inorganic compounds' regulatory and structural roles in body not broken down - maintain their chemical structure some form part of bones and teeth, some for nerve function, enzyme secretion, formation of red blood cells no energy but essential for energy-related processes

Question 35

health risks of poor nutrition

Answer 35

``` vitamin and mineral deficiency increased risk of osteoporosis digestive disorders loss of muscle mass weight gain fatty acid deficiencies depression and low confidence lethargy some cancers lower immune ```

Question 36

positive energy balance (weight management)

Answer 36

results when the energy consumed is greater than that required by the body and thus weight is gained

Question 37

negative energy balance

Answer 37

energy consumed is less than that required by the body and thus weight is lost

Question 38

an energy equilibrium

Answer 38

energy consumed is equal to what body requires = maintain weight