Theme 3: Nutrition

Question 1

what are the roles of carbohydrates?

Answer 1

energy- greatest proportion of energy in the diet
required by all cells but brain, nervous system, and developing RBCs are obligatory users
form parts of DNA and RNA- deoxyribose and ribose
glycoproteins and glycolipids in cell membranes- required for cell signalling

Question 2

what are some sources of carbohydrates?

Answer 2

cereals, vegetables, sugar/confectionary, milk and milk products, meat and meat products, fruits and nuts

Question 3

what are the roles of proteins?

Answer 3

growth of new cells- muscle, bone, skin
repair of tissues
formation of enzymes, transporters, hormones and neurotransmitters
movement- actin and myosin
immune function- antibodies, interleukins
excess used for energy

Question 4

what are some sources of protein?

Answer 4

meat and meat products, cereal products, milk and milk products, vegetables, fish

Question 5

what are the functions of essential fatty acids?

Answer 5

1. as structural components of membranes- phospholipids
2. neural development- myelination
3. as precursors of ecosanoids- leukotrienes, prostaglandins

Question 6

what are sources of essential fatty acids?

Answer 6

linoleic acid and alpha-linoleic acid- plants, vegetable oils, migraine
arachidonic acid- animal fats
EPA and DHA- fish and shellfish

Question 7

what are examples of fat soluble vitamins and their functions and sources?

Answer 7

vitamin A- structural role, growth and reproduction, hormone- tyrannic acid. sources- animal (eggs, butter, milk, liver), plant (carrots)
vitamin D- maintenance of calcium homeostasis. sources- oily fish, eggs, fortified milk/cereals/ yoghurt

Question 8

what are the sources and functions of vitamin B12?

Answer 8

thiamin- part of nerve cell membranes, synthesis and regulation of neurotransmitters, energy metabolism- plays a role in decarboxylation. sources- pork, wholegrains, fortified cereals
cobalamin- found as adenosyl or methyl colbamin, involved in conversion of propionyl CoA to succinylcholine CoA and homocysteine to methionine, needs intrinsic factor

Question 9

what are the functions and sources of folic acid?

Answer 9

functions- amino acid metabolism, purine metabolism, nucleotide synthesis, formation of neural tube in foetus
sources- fortified cereals/breads, red meat, green vegetables

Question 10

what are the functions of the key minerals?

Answer 10

potassium and sodium- nerve and muscle function, water regulation.
magnesium- enzyme function, muscle relaxation.
calcium- building and maintaining bones, nerve transmission, muscle contraction, cofactor in converting prothrombin to thrombin.
iron- haemoglobin, myoglobin, electron transport chain, enzyme cofactor, immune function.
zinc- enzyme cofactor, synthesis of DNA/RNA, protein metabolism, wound healing, insulin function

Question 11

how is energy expenditure calculated?

Answer 11

combination of basal metabolic rate (calculated based on age, sex, weight, height), thermic effect of food (energy expended when eating), non-exercise activity thermogenesis (energy expended during spontaneous/ unstructured physical activity), exercise

Question 12

what is the definition of malnutrition?

Answer 12

deficiencies, excesses or imbalances in a persons intake of energy and/or nutrients

Question 13

what are the types of malnutrition?

Answer 13

specific- deficiency in a particular nutrient
long-standing- the clinical appearance of energy and nutrient deficiencies after a period of inadequate eating, often linked to general neglect
sudden- results from sudden marked change in food intake, often following a significant disruptive life event (berevement, fall)
recurrent- existing inadequate nutritional status followed by a period of illness and subsequent malnutrition leading to repeated cycles of illness.

Question 14

what are the types of protein- energy malnutrition and their presentation?

Answer 14

kwashiorkor (pure protein deficiency without energy deficiency)- stunting, susceptibility to infection, hair colour changes, flaking skin, impaired nutrient absorption, bloated belly- fat accumulates in liver and fluid accumulates in abdomen
marasmus (energy deficiency- emaciated, ketosis

Question 15

what are the consequences of malnutrition?

Answer 15

hypothermia, infertility, respiratory failure, infections, pressure ulcers, DVT and embolism, psychological effects, dependency and loss of earnings

Question 16

how is nutritional status assessed?

Answer 16

1. malnutrition university screening tool (MUST)
2. nutritional assessment- anthropometry (weight and weight change, BMI, arm circumference), bloods (iron status, Ab, CRP, WCC, HbA1c, urea, micronutrients), clinical (investigations for associated diseases), dietary (nutritional requirements, dietary assessment), environmental (ability to care for oneself, impact of symptoms)

Question 17

what are the treatment options for chronic undernutrition?

Answer 17

nutritional support- parenteral (IV), enteral (tube into gut), oral (snacks, fortified food, oral nutritional supplements)

Question 18

what are the different routes for parenteral feeding?

Answer 18

short term- nasogastric, nosaduodenal, nasojejunal

long term- gastrostomy, jejunostomy

Question 19

what is refeeding syndrome?

Answer 19

occurs when food is reintroduced- stimulates insulin secretion and this activates Na/K ATPase pump which moves K into cells. it also drives PO4 and Mg into cells. this results in hypophosphataemia, hypokalaemia, hypomagnesaemia, oedema and thiamine deficiency

Question 20

how us refeeding syndrome prevented and managed?

Answer 20

restore circulating volume
provide oral thiamine and vitamin B before and during first 10 days of feeding
introduce nutrition slowly at low dose
supplement with K, PO4, Mg

Question 21

what are the consequences of vitamin A deficiency?

Answer 21

night blindness, lesions on cornea, blindness, increased susceptibility to infection, decreased immune function, development and growth

Question 22

what are the consequences of vitamin D deficiency?

Answer 22

rickets- bow legs, knock knees

symptoms- fatigue, bone pain, muscle weakness

Question 23

what are the consequences of vitamin E deficiency?

Answer 23

mild deficiency- affects skin causing dermatitis

severe deficiency- neuropathy and haemorrhage

Question 24

what are the consequences of vitamin C deficiency?

Answer 24

scurvy- general weakness, anaemia, gingivitis (gum disease) and skin haemorrhage/ severe easy bruising

Question 25

what are the consequences of vitamin K deficiency?

Answer 25

increased prothrombin (clotting) time- serious cases can lead to a hemorrhagic event

Question 26

what are the consequences of vitamin B deficiencies?

Answer 26

thiamin (B1)- beri beri disease- impaired muscle contraction, impaired cardiac function, oedema, muscle twitches, decreased neurological function/memory loss
riboflavin (B2)- ariboflavinosis- inflammation of the mucous membranes of the oral cavity and pharynx
niacin (B3)- pellagra- dermatitis- red flaky skin, discolouration, thick, crusty, scaly, cracked skin, itchy, burning skin
B12- pernicious anaemia, demyelination, may have increased cancer risk
folate- megaloblastic anaemia, megaloblastic enterocytes, NTD in babies

Question 27

what are the functions of salvia?

Answer 27

1. protection of oral and peri-oral tissues- lubrication, dilution of sugars, antimicrobial, neutralising acid, controlling plaque pH
2. facilitating eating and speech- enhancing chewing and swallowing, digestion, enhancing Tate, enabling speech by lubrication oral tissues

Question 28

what ra the effects of eating disorders on oral health?

Answer 28

hyposalivation- dehydration, vomiting

enamel erosion- bulimia