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Nutrition Flashcards

1
Q

Define nutritional requirements

A

Nutrional requirements are the substances required by an organism to survive grow and reproduce and is both a function of resting energy expenditure requriements and micronutrient consumption for metabolic processes

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2
Q

What are the main determinants of daily caloric requirements?

A

BMI
Activity
Age

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3
Q

For a resting 70kg adult male what is the nutritional requirement

A

1kcal/kg/hr –> 25kcal/kg/day –> Minimum 1800kcal/day but approx 2000-2500kcal/day

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4
Q

For a 70kg adult male what is the carbohydrate requrement

A
  • Carbohydrate - 300-500g of carbohydrate = 4.5g/kg/day with absolute minimum 2g/kg/day = 1200-2000 kcal daily
    ◦ Generally 50-85% of energy intake depending on dietary variety - oxidised to CO2 and water
    ◦ Starch from plants, sucrose and lactose in smaller quantities in food, glycogen in meat in small quantities
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5
Q

What % of energy intake do carbohydrates generally make up>

A

50-85%

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6
Q

What is the minimum carbohydrate intake recommended

A

2g/kg/day

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7
Q

How much fat in g per day should be consumed

A

140g of fat

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8
Q

How much energy does 140g fat contain?

A

1260kcal of energy

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9
Q

What % of intake is fat

A

40% although reduced in less affluent societies

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10
Q

What is the most important source of energy from fats

A

◦ TG the most important as a source of energy through metabolism to free fatty acids oxidsed for energy and glycerol utilised in the glycolytic pathway
◦ essential fatty acids omega 3 and omega 6 cannot be synthesised and are important for cell structure and function

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11
Q

What is the minimum daily protein intake?

A

20-40g to replace amino acid losses

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12
Q

What is the recommended daily intake of protein

A

1g/kg per day so 70g constituting 280kcal of energy

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13
Q

How important is protein intake for energy?

A

◦ Includes non essential amino acids that can be synthesised by the body but importantly essential aminoa cids which cannot be synthesised e.g. phenylalanine
◦ Protein may also be metabolised for energy but at baseline does not occur

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14
Q

What is protein ingestion targeting nutritionally?

A

◦ Includes non essential amino acids that can be synthesised by the body but importantly essential aminoa cids which cannot be synthesised e.g. phenylalanine
◦ Protein may also be metabolised for energy but at baseline does not occur

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15
Q

How much water is recommended per day

A

25-30ml/kg

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16
Q

How much sodium is recommended per day

A
  • Sodium 2mmol/kg/day so 140mmol per day
  • Potassium 1-2mmol/kg/day —> 70mmol/day minimum
  • Chloride —> 1-2 mmol/kg/day —> 70mmol/day
  • Mg and Ca 0.1mmol/kg/dau
  • Trace elements including Fe, zinc, copper, iodine
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17
Q

How much K is recommended per day

A
  • Sodium 2mmol/kg/day so 140mmol per day
  • Potassium 1-2mmol/kg/day —> 70mmol/day minimum
  • Chloride —> 1-2 mmol/kg/day —> 70mmol/day
  • Mg and Ca 0.1mmol/kg/dau
  • Trace elements including Fe, zinc, copper, iodine
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18
Q

How much chloride is reocmmnded per day

A
  • Sodium 2mmol/kg/day so 140mmol per day
  • Potassium 1-2mmol/kg/day —> 70mmol/day minimum
  • Chloride —> 1-2 mmol/kg/day —> 70mmol/day
  • Mg and Ca 0.1mmol/kg/dau
  • Trace elements including Fe, zinc, copper, iodine
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19
Q

How much Mg is recommended per day

A
  • Sodium 2mmol/kg/day so 140mmol per day
  • Potassium 1-2mmol/kg/day —> 70mmol/day minimum
  • Chloride —> 1-2 mmol/kg/day —> 70mmol/day
  • Mg and Ca 0.1mmol/kg/dau
  • Trace elements including Fe, zinc, copper, iodine
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20
Q

How much Ca is recommended per day

A
  • Sodium 2mmol/kg/day so 140mmol per day
  • Potassium 1-2mmol/kg/day —> 70mmol/day minimum
  • Chloride —> 1-2 mmol/kg/day —> 70mmol/day
  • Mg and Ca 0.1mmol/kg/dau
  • Trace elements including Fe, zinc, copper, iodine
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21
Q

What are vitamins

A

organic compounds unable to be synthesied adequately in the body

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22
Q

Where are fat soluble vitamins stored

A
  • Fat soluble vitamins - A, D, E, K stored in the liver
  • Water soluble vitamins - B group and vitamin C
    ◦ Thiamine B1 essential for pyruvate dehydrogenase activity essential for carbohydrate utilisation
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23
Q

What is thiamine essential for

A
  • Fat soluble vitamins - A, D, E, K stored in the liver
  • Water soluble vitamins - B group and vitamin C
    ◦ Thiamine B1 essential for pyruvate dehydrogenase activity essential for carbohydrate utilisation
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24
Q

Define a nutrient

A

a substance which is used by an organism to survive, grow, and reproduce.

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25
Q

What is a macronutrient

A

consumed in large amounts and are used for energy (to meet the energy expenditure) or are incorporated into the structure of tissues.

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26
Q

What is a micronutrient

A

consumed in small amounts and have various other physiological roles

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27
Q

What is resting energy expenditure

A

Resting energy expenditure (REE): the amount of energy consumed (the metabolic rate) by normal physiological processes at rest.
* Normal value (estimate) = ~1kcal/kg/h = 25kcal/kg/day
* For a 70kg adult = 1750kcal/day
* Can be measured by indirect calorimetry, or estimated by formulas (e.g. Harris-Benedict)

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28
Q

WHat is the normal resting energy expenditure?

A

Resting energy expenditure (REE): the amount of energy consumed (the metabolic rate) by normal physiological processes at rest.
* Normal value (estimate) = ~1kcal/kg/h = 25kcal/kg/day
* For a 70kg adult = 1750kcal/day
* Can be measured by indirect calorimetry, or estimated by formulas (e.g. Harris-Benedict)

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29
Q

What is a calorie? What unit of energy does it represent?

A
  • kCal = unit of E used in metabolic studies of humans = the amount of E required to raise the temp of 1g H2O from 15°C → 16°C
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30
Q

How much energy is in 1g of protein

A
  • Calorie content of food = E released from food oxidation in the body
    ◦ CARB = 4kcal/g
    ◦ FAT = 9kcal/g
    ◦ PROTEIN = 4kcal/g
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31
Q

How much energy is in 1g of carbohdyrate

A
  • Calorie content of food = E released from food oxidation in the body
    ◦ CARB = 4kcal/g
    ◦ FAT = 9kcal/g
    ◦ PROTEIN = 4kcal/g
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32
Q

How much energy is in 1g of fat?

A
  • Calorie content of food = E released from food oxidation in the body
    ◦ CARB = 4kcal/g
    ◦ FAT = 9kcal/g
    ◦ PROTEIN = 4kcal/g
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33
Q

What is the process that releases energy from food?

A
  • Calorie content of food = E released from food oxidation in the body
    ◦ CARB = 4kcal/g
    ◦ FAT = 9kcal/g
    ◦ PROTEIN = 4kcal/g
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34
Q

What are the most important sources of energy for resting energy expenditure? What %

A
  • Daily caloric needs from each group: 2000kcal
    ◦ PROTEIN → 1g/kg/day = 70g x 4kacl = 280kcal
    ◦ FAT ~30% → 500kcal = 55g
    ◦ CARB ~45 – 65% → 1220kcal = 300g
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35
Q

How much protein does an ICU patient require per day?

A
  • Requirement: 1.5-2g/kg/day in an ICU patient (200-400g per day lost due to catabolism - some recycling of amino caids but additional 20-40g/day required to maintain balance)
    ◦ 0.6-0.68g/kg/day in healthy adults (more for males) – even more in the elderly, 5x in newborns
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36
Q

How is the resting protein requirement different between ICU patients and well adults?

A
  • Requirement: 1.5-2g/kg/day in an ICU patient (200-400g per day lost due to catabolism - some recycling of amino caids but additional 20-40g/day required to maintain balance)
    ◦ 0.y adults (more for males) – even more in the elderly, 5x in newborns
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37
Q

What is the health adult protein requirement per day?

A
  • Requirement: 1.5-2g/kg/day in an ICU patient (200-400g per day lost due to catabolism - some recycling of amino caids but additional 20-40g/day required to maintain balance)
    ◦ 0.6-0.68g/kg/day in healthy adults (more for males) – even more in the elderly, 5x in newborns
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38
Q

What is an essential amino acid?

A
  • Dietary protein is digested to amino acids (AAs), which can be used to form proteins in the cells of the body.
    ◦ Non-essential AAs: these can be synthesized within the body (primarily in the liver) from intermediates (e.g. other AAs, sugars) – e.g. arginine, glutamine, tyrosine.
    ◦ Essential AAs: cannot be synthesized in the body from intermediates, must be included in nutritional intake – e.g. phenylalanine, methionine.
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39
Q

What is an example of an essential amino acid?

A
  • Dietary protein is digested to amino acids (AAs), which can be used to form proteins in the cells of the body.
    ◦ Non-essential AAs: these can be synthesized within the body (primarily in the liver) from intermediates (e.g. other AAs, sugars) – e.g. arginine, glutamine, tyrosine.
    ◦ Essential AAs: cannot be synthesized in the body from intermediates, must be included in nutritional intake – e.g. phenylalanine, methionine.
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40
Q

Define an essential amino acid?

A
  • Dietary protein is digested to amino acids (AAs), which can be used to form proteins in the cells of the body.
    ◦ Non-essential AAs: these can be synthesized within the body (primarily in the liver) from intermediates (e.g. other AAs, sugars) – e.g. arginine, glutamine, tyrosine.
    ◦ Essential AAs: cannot be synthesized in the body from intermediates, must be included in nutritional intake – e.g. phenylalanine, methionine.
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41
Q

Is there such a thing as too much dietary protein?

A

◦ Increasd protein does not result ni increased protein uptake by tissues
◦ Can cause diarrhoea, enteric organism overgrowth
◦ If absorbed then protein catabolism will result in liberation of ammonia
‣ Urea cycle functioning normally –> excess urea
‣ Urea cycle not functioning normally –> excess ammonia
◦ Excess TPN amino acid slurry 10%w/v resulting in NAGMA

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42
Q

Recmomended ratio of carbohydrates to lipids in diet

A

70:30

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43
Q

What is the CVF of glucose?

A

◦ CVF: 4 kcal/g of glucose

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44
Q

How much carbohydrate should be ingested per day?

A

◦ Requirement: ~70% of caloric goal
‣ 1750kcal x 0.7 = 1225kcal = 306g = approx. 4.5g/kg/day of glucose
‣ Minimum recommended amount is 2g/kg/day – to prevent neuronal hypoglycaemia
◦ 50g/day enough to prevent ketosis

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45
Q

How much glucose do you need to ingest per day to avoid ketosis?

A

◦ Requirement: ~70% of caloric goal
‣ 1750kcal x 0.7 = 1225kcal = 306g = approx. 4.5g/kg/day of glucose
‣ Minimum recommended amount is 2g/kg/day – to prevent neuronal hypoglycaemia
◦ 50g/day enough to prevent ketosis

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46
Q

How does carbohydrate % of caloric intake vary between wealthy and poor societies

A

◦ In affluent societies carbohydrates are about 50% of diet, in poorer societies can by 85%
‣ 300-500g usually

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47
Q

What is the most important source of energy from fats?

A

TG

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48
Q

What is the CVF of fat?

A
  • CVF: 9 kcal/g of fat
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49
Q

What is the minimum fat that can be consumed?

A

at least >10% of dietary intake per day

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50
Q

What is the general fat intake required per day in calories? In g?

A

equirement: ~30-40% of caloric goal (at least >10%)
◦ 1750kcal x 0.3 = 525kcal = 58g = ~1g/kg/day
◦ Normal diet as per Kam/power is 140g of fat providing 1260kcal/day

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51
Q

What are essential fatty acids?

A

◦ Essential fatty acids (omega-3 known as alpha linolenic acid and omega-6 FAs - linolenic acid) – cannot be synthesized in the body and are important for cell structure and function. The 30-40% of caloric intake goal allows for adequate essential FA intake.
‣ 9-12g/day of linolenic acid
‣ 1-3g/day alpha linolineic acid

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52
Q

What is baseline water consumption requirement per day?

A
  • Matches normal daily excretion of water
  • Requirement: 25-30mL/kg/day
  • CVF: 0 kcal/g
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53
Q

Define a mineral

A
  • Inorganic substances (elements) needed in small quantities for normal tissue function.
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54
Q

Requirement per day of Na

A
  • Na – 2mmol/kg (major extracellular cation)
  • K – 1mmol/kg (major intracellular cation)
  • Ca – 0.1mmol/kg (bone health)
  • Mg – 0.1mmol/kg (catalyst for intracellular enzyme reaction)
  • PO4 – 0.1mmol/kg (major anion of ICF. Co-enzyme)
  • Cl – (major extracellular anion) no Australian recommendation, usually intake is the same as Na
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55
Q

Requirement per day of K

A
  • Na – 2mmol/kg (major extracellular cation)
  • K – 1mmol/kg (major intracellular cation)
  • Ca – 0.1mmol/kg (bone health)
  • Mg – 0.1mmol/kg (catalyst for intracellular enzyme reaction)
  • PO4 – 0.1mmol/kg (major anion of ICF. Co-enzyme)
  • Cl – (major extracellular anion) no Australian recommendation, usually intake is the same as Na
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56
Q

Requirement per day of Ca

A
  • Na – 2mmol/kg (major extracellular cation)
  • K – 1mmol/kg (major intracellular cation)
  • Ca – 0.1mmol/kg (bone health)
  • Mg – 0.1mmol/kg (catalyst for intracellular enzyme reaction)
  • PO4 – 0.1mmol/kg (major anion of ICF. Co-enzyme)
  • Cl – (major extracellular anion) no Australian recommendation, usually intake is the same as Na
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57
Q

Requirement per day of Mg

A
  • Na – 2mmol/kg (major extracellular cation)
  • K – 1mmol/kg (major intracellular cation)
  • Ca – 0.1mmol/kg (bone health)
  • Mg – 0.1mmol/kg (catalyst for intracellular enzyme reaction)
  • PO4 – 0.1mmol/kg (major anion of ICF. Co-enzyme)
  • Cl – (major extracellular anion) no Australian recommendation, usually intake is the same as Na
58
Q

Requirement per day of PO4

A
  • Na – 2mmol/kg (major extracellular cation)
  • K – 1mmol/kg (major intracellular cation)
  • Ca – 0.1mmol/kg (bone health)
  • Mg – 0.1mmol/kg (catalyst for intracellular enzyme reaction)
  • PO4 – 0.1mmol/kg (major anion of ICF. Co-enzyme)
  • Cl – (major extracellular anion) no Australian recommendation, usually intake is the same as Na
59
Q

Requirement per day of Cl

A
  • Na – 2mmol/kg (major extracellular cation)
  • K – 1mmol/kg (major intracellular cation)
  • Ca – 0.1mmol/kg (bone health)
  • Mg – 0.1mmol/kg (catalyst for intracellular enzyme reaction)
  • PO4 – 0.1mmol/kg (major anion of ICF. Co-enzyme)
  • Cl – (major extracellular anion) no Australian recommendation, usually intake is the same as Na
60
Q

Requirement per day of Fe

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
61
Q

Requirement per day of Zb

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
62
Q

Requirement per day of Cu

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
63
Q

Requirement per day of I

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
64
Q

Requirement per day of Mn

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
65
Q

Requirement per day of Cr

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
66
Q

Requirement per day of Se

A
  • Fe – 10mg/day (more during menstruation and pregnancy)
  • Zn – 15mg/day (integral to carbonic anhydrase)
  • Cu – 2mg/day
  • I – 150mcg/day (formation & function of thyroid hormone)
  • Mn – 5mg/day
  • Cr – 35mcg/day
  • Se – 70mcg/day
67
Q

Define a vitamin

A

Organic compounds needed in small quantities for tissue and enzyme function – cannot be synthesized adequately in the body.

68
Q

Vitamin A otherwise called? Reequirement per day? Used for? Derived from?

A
  • Fat soluble - stored in large amounts in the liver, excessive intake leads to toxicity
    ◦ Vitamin A – 900mcg/day (retinal eye pigment, epithelial tissue repair, bone function)
    ‣ Can be formed in the gut from Beta carotene in fruits and vegatables
69
Q

Vitamin D derived from? requirement per day?

A

◦ Vitamin D – 5mcg/day (increases with age – essential for bone formation ↑intestinal absorption of Ca2+ + PO42-

70
Q

Vitamin E and K requirements per day? What are they used for?

A

◦ Vitamin E – 10mg/day (fat oxidation, co-factor in ETC) - antioxidant
◦ Vitamin K – 70mcg/day (clotting)

71
Q

What is the thiamine requirement per day?

A

‣ B1 (Thiamin) – 1.2mg/day
* Essential for pyruvate dehydrogenase activity
* ∴Deficiency ↓utilisation of carbs as nutrients
* CNS + PNS depend almost entirely on glucose → degeneration myelin sheath, swelling of neuronal cells, neuritis, cardiac failure

72
Q

Vitamin B2 called? Requirement per day? What is it used for?

A

‣ B2 (Riboflavin) – 1.2mg/day - essential for synthesis of flavoproteins important for oxidative phosphorylation

73
Q

Vitamin B3 called? Requirement per day? used for?

A

‣ B3 (Niacin) – 16mg/day - nicotinic acid - essential for NAD or NADP synthesis, deficiency leading to deramtitis and diarrhoea

74
Q

Vitamin B9 called? Requirement per day? used for?

A

‣ B9 (Folate) – 400mcg/day (RBC maturation) - folic acid concerned with movement of methyl groups from one acceptor to another

75
Q

Vitamin B12 used for? Otherwise called? Requirement per day?

A

‣ B12 (Cyanocobalamin) – 2.4mcg/day - porphyrin ring containing cobalt and requires intrinsic factor for absorption from the stomach. Daily requirement <1microg, half life 1 year . Required for nucleic acid synthesis and integrity of myelin

76
Q

Vitamin C requirement per day? otherwise known as? What is it used fro?

A

◦ Vitamin C – 45mg/day (promotes hydroxylation -> essential for collagen –> its absence causes scurvy with haemorrhage i the skin and internal organs)
‣ Ascorbic acid

77
Q

List some essential amino acids

A

◦ Histidine
◦ Isoleucine
◦ Leucine
◦ Lysine
◦ Methionine
◦ Phenylalanine
◦ Threonine
◦ Tryptophan
◦ Valine
* Included in the protein requirement (1g/kg/day)
* Derived from animal & plant sources of protein

78
Q

List some essential fatty acids

A
  • Omega 3 FA
  • Omega 6 FA
  • Required for neuronal development
  • Not synthesised in body
  • Obtained from fish sources, nuts, green leafy veg
  • Approx 8g/day combined
79
Q

Outline in broad strokes the daily nutrietional requirements of a 70kg adult in macronutrients only

A

Energy components - daily caloric requirements are dependent on BMI, activity and age. For a resting 70kg adult at least 1kcal/kg/hr –> 25kcal/kg/day –> Minimum 1800kcal/day but approx 2000-2500kcal/day
* Carbohydrate - 300-500g of carbohydrate = 4.5g/kg/day with absolute minimum 2g/kg/day = 1200-2000 kcal daily
◦ Generally 50-85% of energy intake depending on dietary variety - oxidised to CO2 and water
◦ Starch from plants, sucrose and lactose in smaller quantities in food, glycogen in meat in small quantities
* Fat - 140g of fat providing 1260kcal of energy
◦ 40% of total calories generally although reduced in less affluent societies
◦ TG the most important as a source of energy through metabolism to free fatty acids oxidsed for energy and glycerol utilised in the glycolytic pathway
◦ essential fatty acids omega 3 and omega 6 cannot be synthesised and are important for cell structure and function
* Protein - 20-40g of protein per day minimum to replace lost amino acids per day, 1g/kg per day so 70g constituting 280kcal of energy
◦ Includes non essential amino acids that can be synthesised by the body but importantly essential aminoa cids which cannot be synthesised e.g. phenylalanine
◦ Protein may also be metabolised for energy but at baseline does not occur

80
Q

Define starvation

A
  • Relative or absolute inadequate energy supply causing the body to harness endogenous reserves
81
Q

What are the 3 phases of the starvation response

A

Glycogenolytic
Gluconeogenesis
Ketogenic

82
Q

Describe the first phase of starvation - how long does it last?

A

◦ Glycogenolytic phase -
‣ Glycogenlysis can buffer glucose for 8-12 hours of fasting systemically from liver stores, muscle glycogen utilised within muscles only.
‣ Free fatty acids are metabolised by beta oxidation with release of acetoacetate and beta hydroxybutyrate in small amounts.
‣ Minor gluconeogenesis from lactate and glycerol

83
Q

What is the 2nd phase of starvation? What is involved?

A

◦ Gluconeogenesis phase -
‣ after 24 hours glucose is produced from gluconeogenesis primarily from amino acids from lean tissues, glycerol from adipose, lactate from RBCs.
* In muscle tissues, protein is broken down to alanine as a substrate for gluconeogenesis by the alanine-glucose cycle
* Alanine formed by transamination of pyruvate derived from oxidation of isoleucine, leucine, valine
* Protein is also broken down into glutamine in muscle tissues which is used by the kidneys as a gluconeogenesis substrate
‣ Increased cortisol concentration reduced protein synthesis in skeletal muscle

84
Q

What is the 3rd phase of starvation? Describe its compoents

A

◦ Ketogenic phase
‣ Ketone bodies gradually rise and replace glucose as the fuel for the CNS as gluconeogenesis declines adn fat becomes the dominant source of energy as lipolysis becomes overwhelmingly stimulated by glucagon stimulation, reducing insulin stimulation, reducing T3 stimulation
‣ Carnititine synthesis requires methyl from methionine derived from muscle breakdown
‣ Brain energy comes from ketones and residual glucose
‣ Cardiac and skeletal muscle derived energy from fatty acid oxidation
‣ Gluconeogenesis declines as a protein sparing mechanism - due to glucagon concentration decline at 10 days of starvation
* Protein breakdown is 75g/day during the first few days but decreased to 20g/day by the third week due to ketone body formation

85
Q

Where is glucose essential to

A
  • Glucose is essential to have available as it is the only energy resource for
    ◦ Brain, CNS
    ◦ Red cells
    ◦ Kidney
    ◦ Intestines
86
Q

What happens to BMR during the starvatino response

A

Declines by 15%

87
Q

What drives the decline in BMR in starvation?

A

Reduced sympathetic and thyroidactivity
Decreased mass of metabolically active tissues

88
Q

How is liver metabolism affected by starvation

A

BMR decreases by 40%

89
Q

How is the heart metabolically affected by starvation

A

Reduced BMR by 30%

90
Q

How are the kidneys affected by starvation

A

BMR reduced by 30%

91
Q

How much glycogen is in the liver

A

100g

92
Q

How much glycogen is in skeletal muscel

A

400g

93
Q

What enzyme is required for release of glucose from glycogenolysis

A

Glucose 6 phosphatase

94
Q

What is the fate of fatty acids in starvation during phase 1?

A

◦ Acetoacetate and beta hydroxybutyrate are produced by the liver from FFA; but for the most part fatty acids release from fat are used for energy in muscle and kidneys. Otherwise most tissues continue to use glucose

95
Q

What are the substrates used by the liver for gluconeogenesis during the first part of the starvation response

A

Lactate
Glycerol

96
Q

What substrates are used for gluconeogenesis after glycogen reserves are exhausted in the liver

A

‣ amino acids from lean tissue - alanine most important amino acid by alanine-glucose cycle to generate glucose in the liver from transamination of pyruvate from oxidation of isoleucine, leucine, valine
‣ glycerol from adipose tissue
‣ lactate from erythrocytes

97
Q

What is the hormonal response in the first 48 hours to starvation

A

‣ Glucagon serge over first 24-48 hours –> peaks at 4 days with marked insulin decrease
‣ Cortisol and adrenaline elvels rise mobilising fat stores –> increased FFA, glucerol; while also suppressing protein synthesis

98
Q

How is lactate converted back to glucose?

A

Cori cycle in the liver

99
Q

How long does phase 2 of the starvation response last?

A

3-4 days

100
Q

What is the principal source of energy in phase 3 of starvation? Why?

A

Fat
decreased insulin, increased glucogagon and decline in T3 stimulate lipolysis

101
Q

Where does the brain derive its energy from in phase 3 of starvation

A

‣ Gluconeogenesis reduced as protein sparing mechnaism - still continues but only supplies 50% of brain and neuronal energy - continues via alanine gluconeogensis in liver

102
Q

What is the source of renal gluconeogenesis?

A

‣ Glutamate the source for renal gluconeogenesis - which becomes more important in late phase starvation

103
Q

For long chain fatty acids to be able to be used by cells for energy what factors are also required?

A

◦ Fat oxidation and ketones synthesised in mitochondria
‣ Long chain fatty acids require carnitine to enter mitochondria
‣ Carnitine synthesis requires a methyl group from methionine from muscle breakdown

104
Q

WHy does carnitine have relevance to late stage starvation?

A

◦ Fat oxidation and ketones synthesised in mitochondria
‣ Long chain fatty acids require carnitine to enter mitochondria
‣ Carnitine synthesis requires a methyl group from methionine from muscle breakdown

105
Q

What occurs during late stage starvation to the hormonal response?

A

‣ At 10 days plasma glucagon is at pre-fasting levels, fat metabolism fully adapted, all other hormone levels remain at same levels as earlier inf asting - cortisol high, adrenaline high, insulin low, T3 low

106
Q
A
107
Q

If you were going to dose TPN what mcronutrients and micronutrient doses might you use?

A
  • Energy 25kcal/kg/day
  • protein: 1.5g/kg/day
  • carbohydrate: 4g/kg/day
  • lipids: 1g/kg/day
  • H2O: 30mL/kg/day + other losses
  • electrolytes - Na 1-2mmol/kg/day, K 1mmol/kg/day, Ca 0.1mmol/kg/day
  • organic vitamins
  • inorganic trace elements
108
Q

What is the energy composition of a TPN bag>

A
  • Energy source → glucose:lipid mixture (70:30 or 60:40 or 50:50)
109
Q

How are carbohydrates given in TPN?

A

Dextrose 50% at 17.5kcal/kg/day for energy
4-5g/kg/day is mininum

To achieve 1400kcal for a patient requiring total 2000kcal per day you have to give 824ml of 50%

110
Q

What is the problem with giving too much glucose in TPN

A

‣ Insulin can be given to aid glucose utilisation (esp in stressed patients)
‣ Need to avoid excess glucose delivery → risk of ↑ BGL, lipogenesis (liver disease), ↑ MR and ↑ CO2 production (delayed ventilatory wean)

111
Q

What is the limiting factor to TPN volume reduction

A

Carbohydrate concentration and amount - low energy density at 3.4kcal/g only

Therefore 940kcal is 1L of 50% dextrose and very hypertonic (1900mosom/L)

112
Q

How is lipid given as TPN

A

10% or 20% intralipid

113
Q

How much lipid is given as a TPN dose?

A

7.5kcal/kg/day for energy; 1g/kg/day required for essential amino acids

114
Q

How much volume would 600kcal of lipid emulsion be

A

550mls

115
Q

What roles do lipids take in TPN?

A

‣ Used as (i) an energy substrate (provides 30-40% daily caloric needs), and (ii) provision of essential FAs (vital for cell membranes and PG synthesis)

116
Q

How does lipid compare in energy density to glucose for TPN?

A

‣ ↑ energy density cf. glucose → 1.1 kcal/mL (10%) and 2 kcal/mL (20%) → thus 1000 kcal can be achieved by 500 mL of 20% or 1L of 10%

Glucose → 3.4 kcal/g only (cf. 4 kcal/g for carbohydrates) → 50% dextrose needs to be given (1 L = 940 kcal)

117
Q

What are the pros and cons to increased lipids in TPN

A

‣ ADvantages of increased lipids - reduced fluid required as more energy dense, prevents fatty acid deficiency
‣ Disadvantages of increased lipids - pancreatitis, immunosuppression, overfeeding

118
Q

What is the protein source in TPN?

A

◦ Nitrogen-source (as symthamin 17) amino acid solution 10% solution 100g/L
‣ 100g/day of protein would be 1000ml of 10% amino acid solution

119
Q

In order to give someone adequate protein how much would you need to give them in volume for TPN

A

◦ Nitrogen-source (as symthamin 17) amino acid solution 10% solution 100g/L
‣ 100g/day of protein would be 1000ml of 10% amino acid solution

120
Q

What is in TPN aside from macronutrients

A

◦ H2O → to maintain body H2O balance and replace losses (Eg. dehydration, bleeding) 25-40ml/kg/day
◦ Electrolytes (Na+ /K+ /Cl- /PO4 3-/Mg2+, Ca2+) → to maintain and replace losses
◦ Vitamin/trace elements → vital to enzyme systems and metabolic pathways in body
‣ Vitamin solutions – (thiamine, folic acid, fat soluble vitamins D, E, K, A, water soluble vitamins B and C)
‣ Trace elements (Zn, Fe, Cu, Mn, Co, Se, I, Cr, Mb)

121
Q

What are the main domains of side effects for TPN

A

Catheter related
Fluid and electrolytes
Metabolic
Other - immune, liver

122
Q

What side effects are there of TPN

A
  • Catheter related
    ◦ Pneumothorax, chylothorax
    ◦ Embolism from air or thrombus
    ◦ Infection
  • Fluid and electrolyte disturbances
    ◦ Fluid overload or hyperosmolar dehydration
    ◦ Electrolyte disturbances - refeeding syndrome –> hypokalaemia, hypophosphataemia
    ◦ Normal anion gap metbaolic acidosis from hyperchloraemia
  • Metabolic disturbances
    ◦ Over or undernutrition
    ◦ Hyperglycaemia delay in endogenous insulin
    ◦ Rebound hypoglycaemia with abrupt cessation due to increased endogenous insulin levels
    ◦ Hyperlipidaemia/hypercholesterolaemia
    ◦ Metabolic bone disease
  • Others
    ◦ Immune suppression due to fat content
    ◦ Liver disease - fatty liver, steatohepatitis
    ◦ Increased PaCO2 due to excessive glucose metabolism
123
Q

What catheter related side effects of TPN are there

A
  • Catheter related
    ◦ Pneumothorax, chylothorax
    ◦ Embolism from air or thrombus
    ◦ Infection
  • Fluid and electrolyte disturbances
    ◦ Fluid overload or hyperosmolar dehydration
    ◦ Electrolyte disturbances - refeeding syndrome –> hypokalaemia, hypophosphataemia
    ◦ Normal anion gap metbaolic acidosis from hyperchloraemia
  • Metabolic disturbances
    ◦ Over or undernutrition
    ◦ Hyperglycaemia delay in endogenous insulin
    ◦ Rebound hypoglycaemia with abrupt cessation due to increased endogenous insulin levels
    ◦ Hyperlipidaemia/hypercholesterolaemia
    ◦ Metabolic bone disease
  • Others
    ◦ Immune suppression due to fat content
    ◦ Liver disease - fatty liver, steatohepatitis
    ◦ Increased PaCO2 due to excessive glucose metabolism
124
Q

WHat fluid and electrolyte side effects of TPN are there?

A
  • Catheter related
    ◦ Pneumothorax, chylothorax
    ◦ Embolism from air or thrombus
    ◦ Infection
  • Fluid and electrolyte disturbances
    ◦ Fluid overload or hyperosmolar dehydration
    ◦ Electrolyte disturbances - refeeding syndrome –> hypokalaemia, hypophosphataemia
    ◦ Normal anion gap metbaolic acidosis from hyperchloraemia
  • Metabolic disturbances
    ◦ Over or undernutrition
    ◦ Hyperglycaemia delay in endogenous insulin
    ◦ Rebound hypoglycaemia with abrupt cessation due to increased endogenous insulin levels
    ◦ Hyperlipidaemia/hypercholesterolaemia
    ◦ Metabolic bone disease
  • Others
    ◦ Immune suppression due to fat content
    ◦ Liver disease - fatty liver, steatohepatitis
    ◦ Increased PaCO2 due to excessive glucose metabolism
125
Q

What metabolic disturbances occur due to TPN

A
  • Catheter related
    ◦ Pneumothorax, chylothorax
    ◦ Embolism from air or thrombus
    ◦ Infection
  • Fluid and electrolyte disturbances
    ◦ Fluid overload or hyperosmolar dehydration
    ◦ Electrolyte disturbances - refeeding syndrome –> hypokalaemia, hypophosphataemia
    ◦ Normal anion gap metbaolic acidosis from hyperchloraemia
  • Metabolic disturbances
    ◦ Over or undernutrition
    ◦ Hyperglycaemia delay in endogenous insulin
    ◦ Rebound hypoglycaemia with abrupt cessation due to increased endogenous insulin levels
    ◦ Hyperlipidaemia/hypercholesterolaemia
    ◦ Metabolic bone disease
  • Others
    ◦ Immune suppression due to fat content
    ◦ Liver disease - fatty liver, steatohepatitis
    ◦ Increased PaCO2 due to excessive glucose metabolism
126
Q

When is TPN indicated?

A

Indicated for those unable to ingest or digest nutrients or to absorb them from GI tract for a prolonged period of time (> 3-4 days) → includes those who have:
* A failed trial of enteral feeding
* Contraindications to enteral nutrition:
◦ GI obstruction
◦ Upper GI strictures and fistulae (Eg. enterocutaneous fistulae) - High output fistulae
◦ Prolonged ileus (Eg. major abdominal surgery where feeding not anticipated for days, paralytic ileus)
◦ Severe pancreatitis
◦ Inflammatory conditions (Eg. IBD or mucositis due to chemotherapy)
◦ Short gut syndromes (Eg. major SB resection) with severe malabsorption

127
Q

What is the Harris Benedict equation?

A

For resting energy expenditure

◦ REE (males) = 66.5 + (13.7 x body weight in kg) + (5.0 x height in cm) (6.8 x age in years)
◦ REE (females) = 66.5 + (9.6 x body weight in kg) + (1.7 x height in cm) (4.7 x age in years) * use ideal body weight * resting energy expenditure in calories * multiply this by a stress factor to allow for effects of disease (no exercise = 1.2, very heavy exercise BD = 1.9) * more accurate to measure REE by indirect calorimetry * most hospitalized patients require 25-30 kcal/kg/day * mechanically ventilated are on the lower aspect of range * burns and trauma patient may require 45 kcal/kg/day * high protein hypocaloric nutrition preferred in obese patents (esp BMI >40)
128
Q

How would you calculate resting energy expenditure based on weight, height and age

A

Harris Benedict equation

◦ REE (males) = 66.5 + (13.7 x body weight in kg) + (5.0 x height in cm) (6.8 x age in years)
◦ REE (females) = 66.5 + (9.6 x body weight in kg) + (1.7 x height in cm) (4.7 x age in years) * use ideal body weight * resting energy expenditure in calories * multiply this by a stress factor to allow for effects of disease (no exercise = 1.2, very heavy exercise BD = 1.9) * more accurate to measure REE by indirect calorimetry * most hospitalized patients require 25-30 kcal/kg/day * mechanically ventilated are on the lower aspect of range * burns and trauma patient may require 45 kcal/kg/day * high protein hypocaloric nutrition preferred in obese patents (esp BMI >40)
129
Q

What physiological determinants (non pathological) would you factor into disease burden and caloric requirements?

A
  • Age, gender, body size
  • Pregnancy
  • Activity level
  • Hydration status
130
Q

What pathologies in particular will influence caloric requirements

A
  • Burns and sepsis → ↑ protein and caloric intake
    ◦ Mild infection add 10% including post op
    ◦ Moderate infection or moderate trauma (multiple fractures) add 20%
    ◦ Severe sepsis or multitrauma intubated add 30-50%
  • Renal failure → ↓ volume, protein and electrolyte (esp K+) content
  • CCF → fluid reduction
  • Hepatic failure → ↓ a.a/protein content to prevent encephalopathy
  • Respiratory failure → ↓ glucose to minimise CO2 production
  • Partial starvation >10% weight loss subtract 0-15% from calculated requirement
  • most hospitalized patients require 25-30 kcal/kg/day
  • mechanically ventilated are on the lower aspect of range
  • burns and trauma patient may require 45 kcal/kg/day
131
Q

Are there any changes to caloric intake for obese patients

A

Hypocaloric high protein nutrition

132
Q

What is the dosing for enteral nutrition as far as calories and macronutrients

A
  • use simple goals based on patient size (25kcal/kg/day + 1.5g protein/kg/day)
133
Q

What is early nutrition by definition

A

Within first 48 hours of ICU stay

134
Q

WHy is the first 48 hours important for nutrition in ICU

A

◦ A critically ill patient has increased energy requirements
◦ Their gut health is compromised because of shock and the stress response state
◦ Mucosal integrity is compromised and bacterial translocation may occur
◦ Delaying nutrition produces the risk of refeeding syndrome once nutrition is eventually reintroduced
◦ Early nutrition addresses these specific concerns

135
Q

Physiologically and nutritionally what is happening to metabolism in the first 48 hours of an ICU stay and why is enteral nutrition useful

A

◦ Hypercatabolic state and increased requirement for macro/micronutrients
◦ Decreased gut health and increased need for trophic stimulus
◦ A greater susceptibility of the patient to the added insults of gut bacterial translocation and malnutrition

136
Q

Evidence base for early nutrition

A
  • No harm from early nutrition, decreased risk of infectious complications when non ICU patients included, infectious complications reduced with EN vs TPN. No mortality benefit and hyperglycaemia a risk which is known to be associated with mortality and morbidity
  • Trophic feeding beneficial
137
Q

Is trophic feeding beneficial

A

Yes

138
Q

Why might early nutrition have disadvantages

A

◦ Poorly tolerated with risk of aspiration
◦ Not be absorbed
◦ Diarrhoea and distension may develop
◦ Utilisation of nutrients may not be normal, no evidence early 100% of goal nutrition prevents muscle catabolism
◦ Hypercatabolic stress response adaptive and working against it may be counterproductive

139
Q

Why is enteral nutrition preferable to TPN

A
  • Practical
    ◦ cheaper
    ◦ simpler
    ◦ for efficient use of nutrients
  • GI benefits
    ◦ stimulates intestinal blood flow
    ◦ prevents disuse atrophy
    ◦ maintain GI mucosal barrier (prevents bacterial translocation and portal endotoxemia)
    ◦ reduced gut associated lymphoid system (GALT) -> becomes a source of activated cells and proinflammatory stimulants
  • fewer complications
    ◦ reduces septic complications compared with TPN
    ◦ avoids CVL complications
    ◦ avoids TPN induced immunosuppression (lipid load)
  • Feeding beneficial
    ◦ improves healing
    ◦ improved weaning and recovery
    ◦ reduced muscle catabolism
140
Q

Why might NG feeds cause problems?

A
  • NG/PEG complications
    ◦ Discomfort
    ◦ sinusitis (N/G)
    ◦ Pressure areas
    ◦ Poor oral hygeine if oral tubes
    ◦ perforation or stricture of oesophagus, pharynx, stomach or bowel
    ◦ PEG use associated with high 30 day mortality (site infection -> abdominal wall infection, bowel obstruction)
  • Feeds going to the wrong spot
    ◦ independent risk factor for VAP (microaspiration, decreased with post-pyloric feeding)
    ◦ misplacement into trachea -> aspiration
  • Side effects
    ◦ diarrhoea
    ◦ metabolic derangement: electrolytes, hyperglycaemia, re-feeding syndrome
    ◦ intolerance: vomiting, excessive aspirates (200-500mL), abdominal distension, constipation or diarrhoea
141
Q
A

Gastro nutrition (7 decks)

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