Chapter 10: Nutrition Flashcards
1
Q
Caloric need
A
Approximately 20-25 cal/kg/d
2
Q
Calories/gram: fat
A
9 Calories/gram
3
Q
Calories/gram: protein
A
4 calories / gram
4
Q
Calories/gram: oral carbohydrates
A
4 calories / gram
5
Q
Calories/gram: dextrose
A
3.4 calories / gram
6
Q
Nutritional requirements for average healthy male
A
- 20% protein calories (1g protein/kg/d; 20% should be essential amino acids)
- 30% fat calories - important for essential fatty acids
- 50% carbohydrate calories
7
Q
% kcal requirement increase: trauma, surgery, or sepsis
A
20% - 40%
8
Q
kcal/day requirement: pregnancy
A
300 kcal / day
9
Q
kcal/day requirement: lactation
A
500 kcal / day
10
Q
Calculation: calorie requirement in burns
A
25 kcal/kg/d + (30 kcal/d x % burn)
11
Q
Calculation: protein requirement in burns
A
1-1.5 g/kg/d + (3g x %burn)
12
Q
What is much of energy expenditure used for?
A
Heat production
13
Q
How does fever affect basal metabolic rate?
A
Fever increased BMR 10% for each degree above 38.0 degrees Celsius
14
Q
Calculation: caloric need in obesity
A
Weight = [(actual weight - ideal body weight) x 0.25] + IBW
15
Q
Calculates basal energy expenditure based on weight, height, age, and gender
A
Harris-Benedict Equation
16
Q
Glucose goals central line TPN
A
Glucose based
- Maximum glucose administration -> 3 g/kg/h
17
Q
Fat based central nutrition
A
Peripheral line parenteral nutrition (PPN) - fat based
18
Q
Fuel for colonocytes
A
Short-chain fatty acids (e.g., butyric acid)
19
Q
Fuel for small bowel enterocytes
A
Glutamine
20
Q
- MC amino acid in bloodstream and tissue
- Releases NH4 in kidney, thus helping with nitrogen excretion
- Can be used for gluconeogenesis
A
Glutamine
21
Q
Primary fuel for most neoplastic cells
A
Glutamine
22
Q
Half-life: albumin
A
18 days
23
Q
Half-life transferrin
A
10 days
24
Q
Half-life prealbumin
A
2 days
25
Normal protein level
6.0 - 8.5
26
Normal albumin level
3.5 - 5.5
27
Acute indicators of nutritional status
Retinal binding protein.
Prealbumin.
Transferrin.
28
Ideal body weight:
- Men
- Women
- Men = 106lb + 6lb for each inch over 5ft
| - Women = 100lb + 5lb for each inch over 5 ft
29
Preoperative signs of poor nutritional status
- Acute weight loss > 10% in 6 months
| - Weight
30
Strong risk factor for morbidity and mortality after surgery
Low albumin (
31
Ratio of CO2 produced to O2 consumed
Respiratory quotient - measurement of energy expenditure
32
Def: RQ > 1
Lipogenesis (overfeeding)
Tx: decreased carbohydrates and caloric intake.
- High carbohydrate intake can lead to CO2 buildup and ventilator problems
33
Def: RQ
Ketosis and fat oxidation (starving)
| - Tx: increased carbohydrates and caloric intake
34
RQ: pure fat utilization
RQ = 0.7
35
RQ: pure protein utilization
RQ = 0.8
36
RQ: pure carbohydrate utilization
RQ = 1.0
37
Post op: diuresis phase
Post op days 2-5
38
Post op: catabolic phase
Post op days 0 -3
39
RQ: pure carbohydrate utilization
RQ = 1.0
40
What is the degree of injury proportional to?
The magnitude of metabolic response
41
When does glycogen deplete?
Depleted after 24-36 hours of starvation on (2/3 in skeletal muscle, 1/3 in liver) -> body then switches to fat.
42
Where is glucose-6-phosphatase found?
Only in the liver.
| None in skeletal muscle: G6P stays in muscle after breakdown from glycogen and is utilized.
43
Gluconeogenesis precursors (x4)
Amino acids (esp alanine).
Lactate.
Pyruvate.
Glycerol.
44
Simplest amino acid precursor for gluconeogenesis.
| - Primary substrate for gluconeogenesis
Alanine
45
Only amino acids to increase during times of stress
Alanine and phenylalanine
46
Where does gluconeogenesis occur in late starvation?
Kidney
47
Why do protein-conserving mechanisms not happen after trauma?
Secondary to catecholamines and cortisol.
48
Main source of energy in starvation and in trauma
Fat (ketones)
| - In trauma, energy is more mixed (fat and protein)
49
% weight loss: pt can tolerate without complications
15%
50
When do you consider Dobhoff tube or TPN?
After about 7 days without eating.
51
Why do you want to feed gut?
To avoid bacterial translocation (bacterial overgrowth, increased permeability due to starved enterocytes, bacteremia) and TPN complications
52
Consider when regular feeding not possible (e.g., CVA) or predicted to not occur for > 4 weeks
PEG tube
53
Utilizes ketones with progressive starvation (normally uses glucose)
Brain
54
Obligate glucose users
Peripheral nerves.
Adrenal medulla.
Red blood cells.
White blood cells.
55
- Occurs when feeding after prolonged starvation / maturation.
- Results in decreased K, Mg, PO4-.
- Causes cardiac dysfunction, profound weakness, encephalopathy.
Refeeding syndrome
56
How do you prevent referring syndrome?
10 - 15 kcal/kg/d
57
- Anorexia, weight loss, wasting
- Thought to be mediated by TNF-alpha
- Glycogen breakdown, lipolysis, protein catabolism
Cachexia
58
Kawshiorkor
Protein deficiency
59
Marasmus
Starvation
60
gram protein = gram nitrogen
6.25g protein = 1g nitrogen
61
Calculate nitrogen balacne
Nin-Nout =
| [protein/6.25] - [24hr urine N + 4g]
62
More protein ingested than excreted (anabolism)
Positive N balance
63
More protein excreted than taken in (catabolism)
Negative N balance
64
g/d: total protein synthesis for a healthy, normal 70kg male
250 g/d
65
- Responsible for amino acid production and breakdown
| - Urea production is used to get rid of ammonia from amino acid breakdown
Liver
66
Amino acids: majority of protein breakdown from skeletal muscle
Glutamine and alanine
67
Broken down by pancreatic lipase, cholesterol esterase, and phospholipase to micelles and free fatty acids
Triacylglycerides (TAGs), cholesterol, and lipids
68
Aggregates of bile salts, long-chain free fatty acids, and monoacylglycerides
- Enter enterocyte by fusing with membrane
Micelles
69
Increase absorption area for fats, helping form micelles
Bile salts
70
Used to synthesize bile salts
Cholesterol
71
Fat soluble vitamins, absorbed in micelles
A, D, E, K
72
Enter enterocyte by simple diffuse
Medium and short chain fatty acids
73
Composition of chylomicrons
90% TAGS
| 10% phospholipids / proteins / cholesterol
74
Where do chylomicrons go after they are formed (form micelles and other fatty acids when they enter the enterocytes)?
Lymphatics by way of the thoracic duct
75
Enter lymphatics along with chylomicrons
Long-chain fatty acids
76
Fatty acids: enter the portal system (same as amino acids and carbohydrates)
Medium- and short-chain fatty acids
77
On endothelium in liver and adipose tissue; clears chylomicrons and TAGs from the blood, breaking them down to fatty acids and glycerol
Lipoprotein lipase
78
On endothelium in the liver and adipose tissue; binds short and medium-chain fatty acids
Free fatty acid-binding protein
79
Used for fuel by cardiac and skeletal muscles
Saturated fatty acids
80
Preferred source of energy for colonocytes, liver, heart, and skeletal muscle
Fatty acids (ketones - acetoacetate, beta-hyroxybutyrate)
81
Used as structural components for cells
Unsaturated fatty acids
82
In fat cells; breaks down TAGS (storage form of fat) to fatty acids and glycol, which are released into the bloodstream; sensitive to growth hormone, catecholamines, glucocorticoids
Hormone-sensitive lipase (HSL)
83
Essential fatty acids
Linolenic, linoleic
84
- Needed for prostaglandin synthesis (long-chain fatty acids)
- Important for immune cells
Essential fatty acids (linolenic, linoleum)
85
What does carbohydrate digestion start with?
Begins with salivary amylase, then pancreatic amylase and disaccharidases
86
Carbs: absorbed by secondary active transport; released into portal vein
Glucose and galactose
87
Carbs: facilitated diffusion, released into portal vein
Fructose
88
Fructose + glucose
Sucrose
89
Galactose + Glucose
Lactose
90
Glucose + Glucose
Maltose
91
What does protein digestion begin with?
Stomach pepsin, then trypsin, chymotrypsin, and carboxypeptidase
92
Released from pancreas and activated by enterokinase, which is release from the duodenum
Trypsinogen
93
What releases enterokinase?
Duodenum
94
Activates trypsinogen
Enterokinase
95
- Activates pancreatic protein enzymes
| - Can auto activate other trypsinogen molecules
Trypsin
96
Broken down to amino acids, dipeptides, and tripeptides by proteases
Protein
97
How is protein absorbed?
Secondary active transport
98
Where are free amino acids released after protein digestion?
Into portal vein
99
Why limit protein intake in liver and renal failure?
To avoid ammonia buildup and possible worsening encephalopathy
100
Branched chain amino acids
Leucine, isoleucine, valine ("LIV")
101
- Metabolized in muscle
- Possibly important in patients with liver failure
- Are essential amino acids
Branched-chain amino acids (LIV: leucine, isoleucine, valine)
102
Essential amino acids
Leucine, isoleucine, valine, arginine, histidine, lysine, methionin, phenylalanine, threonine, and tryptophan
103
General composition TPN
- 10% amino acid
- 50% dextrose
- Electrolyes (Na, Cl, K, Ca, -Mg, PO4, Acetate)
- Mineral and vitamine
- Lipids (given separately from TPN)
104
Deficiency: Chromium
Hyperglycemia, encephalopathy, neuropathy
105
Deficiency: Selenium
Cardiomyopathy, weakness
106
Deficiency: Copper
Pancytopenia
107
Deficiency: Zinc
Poor wound healing
108
Deficiency: Phosphate
Weakness (failure to wean off ventilator), encephalopathy, decreased phagocytosis
109
Deficiency: Thiamine (B1)
Wernicke's encephalaopthy, cardiomyopathy
110
Deficiency: Pyridoxine (B6)
Sideroblastic anemia, glossitis, peripheral neuropathy
111
Deficiency: Cobalamin (B12)
Megaloblastic anemia, peripheral neuropathy, beefy tongue
112
Deficiency: Folate
Megaloblastic anemia, glossitis
113
Deficiency: Niacin
Pellagra (diarrhea, dermatitis, dementia)
114
Deficiency: Essential fatty acids
Dermatitis, hair loss, thrombocytopenia
115
Deficiency: Vitamin A
Night blindness
116
Deficiency: Vitamin K
Coagulopathy
117
Deficiency: Vitamin D
Rickets, osteomalacia, osteoporosis
118
Deficiency: Vitamin E
Neuropathy
119
Glucose is utilized and converted to lactate in muscle
Cori Cycle
120
Goes to liver and is converted back to pyruvate and eventually glucose via gluconeogenesis
Lactate
