Theme 3: Nutrition Flashcards
what are the roles of carbohydrates?
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
what are some sources of carbohydrates?
cereals, vegetables, sugar/confectionary, milk and milk products, meat and meat products, fruits and nuts
what are the roles of proteins?
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
what are some sources of protein?
meat and meat products, cereal products, milk and milk products, vegetables, fish
what are the functions of essential fatty acids?
- as structural components of membranes- phospholipids
- neural development- myelination
- as precursors of ecosanoids- leukotrienes, prostaglandins
what are sources of essential fatty acids?
linoleic acid and alpha-linoleic acid- plants, vegetable oils, migraine
arachidonic acid- animal fats
EPA and DHA- fish and shellfish
what are examples of fat soluble vitamins and their functions and sources?
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
what are the sources and functions of vitamin B12?
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
what are the functions and sources of folic acid?
functions- amino acid metabolism, purine metabolism, nucleotide synthesis, formation of neural tube in foetus
sources- fortified cereals/breads, red meat, green vegetables
what are the functions of the key minerals?
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
how is energy expenditure calculated?
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
what is the definition of malnutrition?
deficiencies, excesses or imbalances in a persons intake of energy and/or nutrients
what are the types of malnutrition?
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.
what are the types of protein- energy malnutrition and their presentation?
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
what are the consequences of malnutrition?
hypothermia, infertility, respiratory failure, infections, pressure ulcers, DVT and embolism, psychological effects, dependency and loss of earnings
how is nutritional status assessed?
- malnutrition university screening tool (MUST)
- 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)
what are the treatment options for chronic undernutrition?
nutritional support- parenteral (IV), enteral (tube into gut), oral (snacks, fortified food, oral nutritional supplements)
what are the different routes for parenteral feeding?
short term- nasogastric, nosaduodenal, nasojejunal
long term- gastrostomy, jejunostomy
what is refeeding syndrome?
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
how us refeeding syndrome prevented and managed?
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
what are the consequences of vitamin A deficiency?
night blindness, lesions on cornea, blindness, increased susceptibility to infection, decreased immune function, development and growth
what are the consequences of vitamin D deficiency?
rickets- bow legs, knock knees
symptoms- fatigue, bone pain, muscle weakness
what are the consequences of vitamin E deficiency?
mild deficiency- affects skin causing dermatitis
severe deficiency- neuropathy and haemorrhage
what are the consequences of vitamin C deficiency?
scurvy- general weakness, anaemia, gingivitis (gum disease) and skin haemorrhage/ severe easy bruising
what are the consequences of vitamin K deficiency?
increased prothrombin (clotting) time- serious cases can lead to a hemorrhagic event
what are the consequences of vitamin B deficiencies?
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
what are the functions of salvia?
- protection of oral and peri-oral tissues- lubrication, dilution of sugars, antimicrobial, neutralising acid, controlling plaque pH
- facilitating eating and speech- enhancing chewing and swallowing, digestion, enhancing Tate, enabling speech by lubrication oral tissues
what ra the effects of eating disorders on oral health?
hyposalivation- dehydration, vomiting
enamel erosion- bulimia
