Nutrition - Digestion and Absorption

Question 1

what are the primary causes of nutritional deficiency

Answer 1

inadequate selection of food, age, income and education

Question 2

what are the secondary causes of nutritional deficiency

Answer 2

systemic disorders that interfere with ingesting, digestion, absorption, transport and use of nutrients

Question 3

what are the required nutrients for dental health

Answer 3

calcium
phosphorus
vitamin A, C and D
fluoride

Question 4

what are bad nutrients for dental health

Answer 4

carbohydrates
sweet and sticky foods
sugars
carbonated drinks
fruit juices

Question 5

which illnesses are associated with vitamin D deficiency

Answer 5

preenclampsia
childhood dental caries
periodontitis
autoimmune disorders
infectious diseases
cardiovascular disease
deadly cancers
type 2 diabetes
neurological disorders

Question 6

why is vitamin D important for dental health

Answer 6

relevent mineral density to help absorb, carry, and deposit calcium in the bones that support your teeth
lack can lead to caries, or brittle teeth

Question 7

what are the primary reasons for nutrient imbalance

Answer 7

inadequate intake
malabsorption
nutrient wasting

Question 8

which medical conditions can cause nutrient imbalance

Answer 8

crohns
cystic fibrosis
bariatric surgery
parentral and tube feeding
HIV infection
malignancies

Question 9

what does nutrition mean

Answer 9

describes the processes whereby cellular organelles, cells, tissues, organs and the body obtain necessary substances obtained from foods to maintain structural and functional integrity

Question 10

what is an example of an oligosaccharide

Answer 10

fructooligosaccharides
dextrins

Question 11

what is galactose

Answer 11

component of lactose

Question 12

what is sucrose formed from

Answer 12

glucose and fructose

Question 13

what is maltose formed from

Answer 13

two glucose molecules

Question 14

what forms lactose

Answer 14

glucose and galactose

Question 15

what is the most important risk factor for caries

Answer 15

dietary free sugars

Question 16

how much of energy intake is recommded to be taken up by free sugars

Answer 16

less than 10%

Question 17

what are free sugars

Answer 17

those added and naturally present

Question 18

what are the common characteristics of dietary fibres

Answer 18

dietary fibres are saccharides of plant origin
they are resistant to digesting and absorption in the small intestine
fermentation in the colon produces short chain fftty acids that are absorbed and metabolised in various parts of the body

Question 19

what are the three basic non starch polysaccharides

Answer 19

acetic acid
propionic acid
butyric acid

Question 20

what are fructains

Answer 20

oligosaccharides composed of fructose eg inulin and oligofructose

Question 21

why are inulin and oligofructose prebiotics

Answer 21

they are non digestable food ingredients that selectively stimulate growth and or the activity of a number of potentially health stimulating intestinal bacteria

Question 22

what are the natrual sources of inulin and oligofructose

Answer 22

chicory roots
jerusalem artichokes
garlic

Question 23

what is the basic process of digestion

Answer 23

hydrolysis
major types of macronutrients in food are primarily digested by hydrolysis
requires enzymes specialised in cleaving specific types of bonds like alpha amylase

Question 24

what must happen to polysaccharides prior to being digested

Answer 24

they must be digested to become monosaccharides

Question 25

what is starch digested to become

Answer 25

maltose maltotriose limit dextrins

Question 26

what does maltase do

Answer 26

cleave maltose into two molecules of glucose

Question 27

what does lactase do

Answer 27

cleave lactose into glucose and galactose

Question 28

what does sucrase do

Answer 28

cleave sucrose into glucose and fructose

Question 29

what are oligosaccharides digested as

Answer 29

SCFA (short chain fatty acid)

Question 30

give a summary of carbohydrate digestion and absorption

Answer 30

polysaccharides are broken down by salivary amylase and pancreatic amylase to become disaccharides and trisaccharides which are broken down by intestinal surface enzymes. they then become monosaccharides which are exclusively absorbed as monosaccharides

Question 31

where in the intestine are diasaccharides broken down

Answer 31

brush border

Question 32

why is glucose and fructose not digested

Answer 32

can be absorbed as they are

Question 33

what is lactose intolerance

Answer 33

loss of lactase weaning the lactose is not hydrolysed, and passes to the bowel to become a short chain fatty acid.

Question 34

what are the sugar transporter families

Answer 34

GLUT family and sodium glucose transport family

Question 35

how many kg of monosaccharides can the human intestine transport

Answer 35

10

Question 36

what are the metabolic and hormonal responses after a meal intake

Answer 36

increase in blood glucose increase in blood triglyceride levels decrease in blood non esterised fatty acids and beta hydroxybutyrate increase insulin decrease glucagon

Question 37

what is the three fates of dietary carbohydrates

Answer 37

glucose uptake by muscle liver and muscle glycogen synthesis oxidative disposal of glucose in the muscle and other tissues

Question 38

what does fat refer to

Answer 38

dietary triglycerides

Question 39

what are lipids

Answer 39

water insoluble compounds that most triglycerols are in the form of in the diet

Question 40

what are the three main dietary lipids

Answer 40

triaglycerols phospholipids steroles

Question 41

what is the phospholipid make up

Answer 41

phosphorus and 2 fatty acids

Question 42

what is the sterol make up

Answer 42

derived from fatty acids

Question 43

what are the structural factors affecting properties of fatty acids

Answer 43

number of carbon atoms presence of double bonds

Question 44

what are TAGs

Answer 44

trans alanyl glutamine

Question 45

summarise digestion of TAGs

Answer 45

emulsification by bile acid and the formation of small micelles hydrolysis of TAG by pancreatic lipase to liberate fatty acids to form 2 monoglycerol

Question 46

what is the issue with fat digestion

Answer 46

fats are insoluble in water and the enzymes are in aqueous phase

Question 47

what are emulsifying agents

Answer 47

fatty acids monoglycerides cholesterol lecithin protein bile acids

Question 48

what are micelles

Answer 48

aggregates of molecules like those formed by detergent

Question 49

label this micelle

Answer 49

Question 50

summarise fatty acid absorption

Answer 50

at the brush border, the lower pH at mucosa reduces the solubility of lipid in micelles the fatty acids are absorbed by diffusion or through carrier proteins

Question 51

what are chylomicrons

Answer 51

low density lipoproteins

Question 52

how long do fatty acids need to be to go straight to the portal blood

Answer 52

less than 12 carbons long

Question 53

what happens to fatty acids longer than 12 carbons

Answer 53

triglyceride reformed in cell coated in protein, and the phospholipid and cholesterol are enclosed in vesicles

Question 54

where do chylomicrons go

Answer 54

lymphatics via lacteals

Question 55

describe the metabolism of dietary fats

Answer 55

fatty acids and monoglycerides enter the cells of the intestinal wall within the enterocytes, fatty acids and monoglycerols are reesterified to form new TAG molecules

Question 56

describe cholesterols fate in digestion

Answer 56

half is absorbed, remainder is lost in faeces

Question 57

describe the transportation of exogenous fat

Answer 57

newly formed TAGS are packed with phospholipids and proteins to form chylomicrons, which also contain dietary cholesterol esters these molecules flow slowly through lymph and enter circulation

Question 58

describe the composition of newly secreted chylomicrons

Answer 58

the core is made up of TAG and cholesterol esters the surface contains unesterified cholesterol, phospholipids, apoproteins B48 and A1

Question 59

how much of total protein intake is made up of animal protein foods

Answer 59

60-70%

Question 60

describe the structure of dietary proteins

Answer 60

long chains of amino acids bound together

Question 61

are whole proteins absorbed

Answer 61

rarely

Question 62

what are whole proteins digested to become

Answer 62

amino acids or di/tripeptides

Question 63

what does stomach acid do

Answer 63

denature the proteins, activate zymogen and stimulate proteolytic enzyme secretion

Question 64

what is a zymogen

Answer 64

the inactive form of a hormone such as pepsinogen

Question 65

how many proteins are absorbed by stomach pepsin

Answer 65

20%

Question 66

what are some proteases

Answer 66

pepsin trypsin chymotrypsin carboxypeptidase

Question 67

how long can peptides be to be absorbed

Answer 67

no longer than four amino acids

Question 68

what is the function of macronutrients

Answer 68

provide energy in sufficient quantities provide a range of building blocks provide essential nutrients we cannot make ourselves

Question 69

what are the roles of dietary fats

Answer 69

energy provision essential fatty acids help carry fat soluble vitamins enable storage of energy structural role in cell membranes metabolic functions

Question 70

how is lactose intolerance diagnosed

Answer 70

hydrogen in the breath