Final Review Flashcards
(148 cards)
1
Q
How does digestion and absorption of proteins happen in the stomach?
A
HCl uncoils protein strands and activates stomach enzymes: protein—-(Pepsin,HCl)—> smaller polypeptides
2
Q
How does digestion and absorption of proteins happen in the small intestine and pancreas?
A
Cholecystokinin(hormone released in upper small intestine) triggers pancreas to secrete digestive enzymes once digestion products leave the stomach
Digestive enzymes are activated and continue to break down peptides into di-/tripeptides and free amino acids, which are taken up by intestinal cells
3
Q
Ingested dietary proteins do or do not directly become body proteins(i.e. Become muscle).
A
Do not; Instead dietary proteins consumed supply the amino acids which are used for synthesis and numerous other function of protein in the body
4
Q
The human body does or does not store protein or amino acids which means we need a continual source.
A
Does Not; we do need a continual source
5
Q
What are some examples of multi-functionality of protein……
A
Enzymes, hormones, structural components
Immune function, transporters, fluid balance
Buffering, pH regulation, synthesis
Growth, energy
6
Q
What are important factors dictating protein properly being used to fulfill physiological protein functions
A
When calorie and carbohydrate intake is sufficient then amino acids are used appropriately to meet the various function of protein
Factors that most influence the use of amino acids for body fuel or energy as contrasted to properly being used for the various protein function include: being in an energy deficit state; insufficient daily dietary carbohydrate intake
7
Q
Proteins provide structure for:
A
cellular membranes, connective tissue(collagen), tendons, arterial walls (elastin); skin, hair, nails(keratin), transport proteins (albumin, lipoproteins), hemoglobin, immunoglobins, antibodies, hormones, enzymes
8
Q
What is the average Protein turnover
A
synthesis and degradation of (250 g/d)
9
Q
What is Net protein (or nitrogen) balance
A
Difference between rates of protein synthesis (PS) + breakdown(PB)
Goal during adulthood(non-pregnant or body building) is balance
10
Q
What is a positive net protein(or nitrogen balance)
A
Protein synthesis>Protein breakdown = retaining protein
Needed for growth, pregnancy, recovery
11
Q
What is negative net protein(or nitrogen balance)
A
Protein breakdown> protein synthesis= protein loss
In malnutrition, illness,injury, protein breakdown=increased breakdown to meet increasing energy needs
12
Q
What are the different types Body proteins and where are they found?
A
Visceral protein: internal organs, blood cells, serum proteins; more rapid turnover compared to skeletal muscle protein
Somatice protein: skeletal muscle protein
Considerations for assessing protein status
13
Q
Glycine is a precursor for…
A
Heme (O2 transport)
Purines (nucleic acid bases DNA/RNA)
Creatine (muscle contraction)
14
Q
Tryptophan is a precursor of …..
A
niacin and serotonin
-nicotinic acid, NAD, NADP- coenzymes for redox reactions
-serotonin, neurotransmitter(sleep, mood, appetite)
15
Q
Phenylalanine is a precursor of ..
A
Tyrosine, which is used in the synthesis of..
Melanin(pigments in hair,skin,eyes)
Epinephrine, Norepinephrine(neurotransmitters that stimulate CNS)
Thyroxine(thyroid hormones-metabolic rate)
16
Q
Essential Vs Nonessential amino acids
A
Indispensable: Histidine, Isoleucine, Leucine, Lysine, Methionine, Phenylalanine, Threonine, Tryptophan, Valine
Dispensible: Alanine, Aspartic Acid, Asparagine, Glutamic acid, Serine
17
Q
The concept of “essential” amino acid references…
A
The inability of body for ‘de novo” synthesis
18
Q
What is the essential amino acid pneumonic
A
TV TILL PM, Hi
T=threonine, V=valine, T=tyrosine, I=isoleucine, L=leucine, L=lysine, P=phenylalanine, M=methionine, Hi= histidine
19
Q
What are examples of when dietary sources is required when endogenous synthesis can’t meet metabolic demand(need conditionally indispensable amino acids)
A
Physiological circumstances-immature organ (cysteine,proline)
Hypercatabolic conditions- infection, trauma, stress(glutamine
Disease states-CRF(serine)
20
Q
How do we determine amino acid requirements?
A
Nitrogen balance studies
Direct amino acid oxidation (DAAO)
Indicator amino acid oxidation (IAAO)
Metabolic demand
21
Q
What does FFM=BCM+ECF+ECS stand for?
A
Where, BCM= body cell mass(muscle, viscera, blood, brain cell matter)
Where, ECF= extracellular fluid(plasma and intersitial fluid)
Where, ECS= extracellular solids (organic/inorganic compounds(collagen; bone matrix)
22
Q
Fat free mass includes…
A
Muscle, bone, fluid, all except for lipid
23
Q
Lean body mass includes…
A
Essential body fat at 2-3%
-LBM=BCM(body cell mass) + ECF(extracellular fluid) +extracellular solids
24
Q
What is considered essential body fat?
A
Brain, cell membranes, muscle, bone marrow
25
Tests of immunocompetence..
Can be used as functional indicators of PEM (supporting evidence only)
26
DCH stands for
Delayed Cutaneous hypersensitivity (DCH)
Intradermal injection of antigens
Local inflammatory response is impaired
27
Total Lymphocyte count can indicate
Reduced amounts of mature lymphocytes in malnutrition; TLV <1500 cells/mm3
Reference range: 200-3500 cells/mm3
28
What does Marasmus mean and how does it present
Means to “waste away”
Appears to be just skin and bones; wasted muscle mass and adipose tissue
Develops gradually
29
How does Kwashiorkor present?
Skin manifestations: rashes/pigment changes
thin , sparse hair
Presence of edema and some subcutaneous fat and muscle mass
Rapid onset
30
What is Protein energy malnutrition(PEM) and how does it affect the body?
Condition resulting from insufficient amounts of energy and protein
Can affect people of all ages
Most devastating in children: failure to grow, adverse LT effects on organs, brain, poor cognitive growth
31
What are the two things that are analyzed in nutrition focused physical exam
Malnutrition assessment
Nutrient deficiency assessment
32
What goes into estimating muscle mass using the CHI
Compare 24 hr urinary creatinine excretion with a standard base on height
CHI>80% normal
CHI= 60%- 80%- mild protein depletion
CHI- 40%-60%- moderate depletion
CHI<40%- severe depletion
33
What are the limitations of using urinary creatinine excretion
Slowly responds to changes in nutritional status
Accurate measurements require: normal kidney function and filtration, elimination or standardization of meat in diet
Collecting urine samples throughout the course of day
CHI may not always be accurate for elderly
34
What goes into measuring 3-methylhistidine excretion for muscle mass
Found in contractile proteins of skeletal muscle
Released during protein catabolism
Cannot be reused; excreted in urine
Excretion is an index of muscle catabolism
35
What are the limitations of measuring 3-methylhistidine excretion for muscle mass?
Not derived exclusively from muscle protein
Caution in states where protein oxidation is altered
36
What are three other ways that are indirect measures to assess protein status
Anthropometrics: mid-arm circumference +triceps skinfold thickness
Muscle weakness
Clinical signs (growth in infants and children)
37
What are the three majors sources of dietary protein
-Animal products
-plant products(grains, nuts/seeds, legumes and vegetables)
-exogenous proteins (EAA,NEAA and additional nitrogen)
38
Quality of protein:
-expression of its ability to provide the N+AA requirements for growth, maintenance and repair
39
Quality of protein is mainly determined by 2 factors:
-digestibility
-Amino acid composition
40
Define digestibility of protein:
-proportion of dietary N or amount of AA absorbed
-varies based of protein source, preparation, and other foods consumed with source
41
What is the major factor that affects plant protein digestibility:
-Plant proteins are often contained within cell walls that are resistant to human digestion
42
Define amino acid composition or profile:
-if intake of one single EAA in the diet is less than the requirement it limits the utilization of other AA and prevents normal rates of PS
-limiting AA=EAA found in the shortest supply relative to the amounts needed for protein synthesis in the body
Determines nutritional value of protein
43
What is a high quality/complete protein
-contains sufficient amounts of all EAA in quantities required by humans to prevent deficiency
Meat, poultry, fish, eggs, milk
Exception gelatin
44
What is a low quality/ incomplete protein
-low in one or more EAA to support human maintenance and growth
-plant proteins; vegetable, legumes, nuts, seeds, grains
Exception: quinoa, soy, buckwheat
45
How do you evaluate protein quality?
-Amino acid scoring
46
How do you determine amino acid score:
-amount of each EAA in 1 g of test protein/by “ideal” amount for that EAA in 1g of reference protein
EAA in the greatest deficit= limiting AA
47
What is the main problem with the amino acid score?
-Relies on a chemical procedure; fails to estimate digestibility of protein
48
What is the gold standard for assessing protein quality?
-protein digestibility corrected amino acid score
Amino acid score x true digestibility %
Accounts for AA composition and the fact that not all of the protein ingested is absorbed
49
What is the proposed concept for leucine as an additional indicator of protein quality?
-Dietary protein quality may refer to the ability of a protein source to support the increase in muscle protein synthesis(MPS) after ingestion
-Recent studies have suggested that leucine is the most potent AA responsible for stimulating postprandial MPS
50
Leucine rich protein sources such as…… are better at stimulating muscle growth than sources with less leucine such as…..
1.whey
2.soy
51
True or False? Plant proteins can be low in certain EAA. Thus, a vegan must consume “complimentary mixtures” of plant proteins to meet their EAA requirements.
-False
-Plant proteins are NOT missing EAA, just have lower amounts of certain EAA
-Complimenting with various sources or plant proteins just makes the diet more interesting
52
True or False? Different plant proteins must be consumed together in the same meal to achieve a high nutritional value(ie to be used)
-False
-Idea that all EAA must be consumed together in 1 meal or they cannot be used comes from a ridiculous abstract published in 1947
-not necessary to balance the AA profile at each meal
53
What is the EAR of protein?
-0.66g/kg/day
54
What is the RDA protein for adults?
0.8g/kg body weight
55
Higher protein diets-risks of overconsumption are…
-Increased risk of dehydration
-possible kidney damage
-possible bone damage (osteoporosis)
-increased CVD risk (lipid levels)
-increased cancer risk (red/processed meat)
-obesity
However evidence is insufficient to establish a UL
56
Higher protein diets-potential benefits include…
-increased muscle mass
-decreased CVD risk (TG levels, BP, body weight)
-better control of diabetes (PPBG and insulin response)
-weight loss/lower body weight (fat/LBM changes, increased satiety)
57
What are some conditions that affect protein/AA requirements
-pregnancy and lactation inc. protein needs
-severe burn injuries inc. protein needs
-infection inc. protein needs
-cancer inc. protein needs
58
Energy is required to sustain the body’s functions, what are some examples?
Respiration by lungs, digestion, maintenance of core body temp, beating of heat and blood circulation
59
-How do we sustain these body processes?
Eat, the energy in foods is released by oxidation
The heat produced is used to maintain core temperature
60
Metabolizable energy=
GEI-GEfeces-GEurine
61
Define chemical energy in terms of metabolism
Gross energy, total combustible E content measured by bomb calorimetry
62
Define absorbed energy in terms of metabolism
Not completely digested/absorbed, some E lost in stool
63
Atwater factor
Physiological fuel value. Factors for heat of combustion, coefficient of availability, and available energy for nutrients in a fixed diet
64
How do we determine metabolizable energy
Measure it (ME=GEI-GEfeces-GEurine)
Atwater
65
Food intake is controlled by…
Physiological, social, metabolic, and psychological factors
66
Energy homeostasis is achieved on coordinated hormone signaling from different systems like the…..
PNS,CNS, and endocrine system
67
Afferent signals sent from… to …… stimulate or inhibit release of peptides that regulate energy intake
Periphery to hypothalamus
68
What are the major components of energy expenditure?
Basal metabolic rate, thermic effect of food, energy expenditure of activity(physical activity/exercise, non-execercise activity thermogenesis(NEAT));thermoregulation
69
Define basal metabolic rate (BMR)
EE needed to sustain basal cost of living/survival
70
Define resting metabolic rate (RMR)
EE under resting resting conditions
71
What are three major validated ways to measure energy expenditure
Direct calorimetry
Indirect calorimetry
Heart rate monitoring
72
What is the basic principle of direct calorimetry
Energy used by the body is ultimately degraded to heat
73
What is the basic principle of indirect calorimetry
Gas exchange proportional to oxidative metabolism; relates directly to kcals burned/amount of combustion
74
-RQ and substrate oxidation:What does RQ of 1 mean, 0.7, and 0.85
1= 100% carbohydrates
0.7= 100%fat
0.85= mixed post-absorptive
75
Doubly labeled water:
-basic principle: body H20 becomes labeled by 2H2 18O
Basis for determining the estimated energy requirements for humans
Gold standard for measuring total EE
76
What are the advantages and disadvantages of Doubly labeled water?
-Advantages: very accurate, safe, non-invasive, non-restrictive, easily administered
-Disadvatages: very expensive, not easy to do in clinical settings
77
What are the basic principles related to BMR?
-age, height, growth, body composition(age, gender, physical activity(effect lean body tissue), stresses, environemental temp, fasting, malnutrition, hormones, smoking, caffeine, sleep
78
Overall BMR decreases with ….. And which sex has a higher BMR throughout lifespan?
age; males have a higher BMR throughout lifespan
79
What causes the loss of lean mass with aging?
-sarcopenia
80
What are the factors that increase basal metabolism?
-Greater LBM or muscle mass;male gender; changes in core body temp; thyroid hormones, aspects of nervous system(stress); caffeine and tobacco use; growth stages of life cycle
81
What the factors that decrease basal metabolism
-restricted calorie intake
-lower secretions of thyroid hormones
-loss of LBM
82
What are three major components of total energy expenditure?
-thermic effect of food (TEF)
-non exercise activity thermogenesis (NEAT)
-physical activity
83
What was the effect of starvation on body temperature?
-keeping warm was a struggle
84
What was the effect of starvation on endurance?
-it decreased
85
What are some other issues that they faced when starved?
-unremitting hunger; weakness, depression, sense of feeling old, lack of interest in socializing, extreme emotion,social and behavioral changes, dizziness, extreme tiredness. Muscle soreness, hair loss, ringing in ears
86
What was the effect of starvation on reproduction?
-no sex drive
-decreased sperm count(volume and viable)
87
What was the effect of starvation on intelligence and personality?
-no loss in intelligence but had mental lethargy
-personality changes
88
What were the functions that were resistant to starvation?
-intelligence, sight, hearing, speed of movement
89
What are some effects of the body trying to adapt to starvation
metabolic shift, bradycardia, depressed blood circulation, decrease in body temp, dec. in basal metabolism
90
When in recovery, what type of body masss was slower to recover?
-lean body mass
91
What are the main functions of calcium?
stored in bones and teeth (99%),primarily in the form of hydroxyapatite,supports bone and teeth structure, Ca bank if blood levels drop
Blood, muscle, ECF(1%),needed for blood clotting, vascular constriction/dilation, nerve conduction, enzyme regulation, muscle contraction
92
Where is calcium absorbed?
-Across the intestinal mucosa
93
At low or moderate levels of intake calcium absorption is dependent on
-active transport, active vitamin D
94
At higher levels of intake calcium absorption is dependent on
-passive diffusion, movement between mucosal cells based on Calcium gradient
95
Calcium absorption varies with
-intake, type of calcium salt, age, components of diet
96
What are the 3 main hormones involved in calcium homeostasis?
-parathyroid hormone (PTH), calcitriol (active metabolite of Vit D), calcitonin
97
With a decrease in calcium intake or absorption…
-circulation Calcium decline, trigger release of PTH
98
What are the 3 target organs PTH acts on to restore circulation Calcium and how do they effect calcium regulation
-kidney, intestines, bones
-kidney(increase the synthesis of calcitriol and promotes Ca reabsorption)
-intestine (calcitriol increase calcium absorption)
-bones (induce reabsorption, releases calcium into blood)
99
When there is a rising blood calcium level signals the ..
-thyroid gland to secrete calcitonin
100
When there is falling blood calcium level signals the..
-parathyroid gland to secrete parathyroid hormone
101
What are the two main easy to assess calcium status?
-biochemical (serum calcium, serum ionized calcium, protein bound calcium)
-bone mineral content/density(bone densitometry, dual energy X-ray absorptiometry, CT scans)
102
Define bone remodeling:
process of osteoclastic bone resorption(breakdon) and osteoblastic bone formation
-purpose to regulate calcium homeostasis, repair damage from everyday stream shape the skeleton during growth
103
What are the risk factors for calcium deficiency
-fat malabsorption, immbolization, decreased GI transit time
-dietary patterns: lactose intolerance, vegan, dairy free
104
What happens when there’s calcium deficiency in infants and children
-stunting of growth, poor quality of bones and teeth
-malformation: rickets(co-deficiency of Vit D), bow legs, enlargement of bones around joints, rachitic rosary
105
What are some barriers to vitamin D synthesis
-limited sunlight exposure
-elderly
-dark skin
-those with liver or kidney disease, fat malabsorption, obesity
106
Calcium deficiency over the years can lead to..
-osteomalcia and osteoporosis
107
What are some osteoporosis risk factors
-asian, white, family history, inactivity, low dietary calcium/vitamin, menopause, postmenopausal, previous fracture, smoking/alcohol, thin/frail, medications and diseases
108
Definition of kyphosis
-compression of the vertebrae
109
What do metanalysis show for trials of Ca and vitamin D increase to prevent fractures and bone loss in poeple older than 50?
-calcium alone or increase vit D effective in preventative tx of osteoporosis
110
What is concluded for current recommendations for high calcium intake to prevent fractures?
dietary calcium itnake is not associate with risk of fractire and there is currently no evidence that inc. calcium intake prevents fractures
-calcium supplements have small inconsistent benefits on fracture prevention
-increaseing calcium intake, through calcium supplements or dietary sources should not be recommended for fracture prevention
111
What is concluded of long term intakes of calcium in women?
-high intakes of calcium in women are associated with higher death rates from all causes and cardiovascular disease but not from stroke
112
What are some associates with inadequate calcium intake?
-hypertension, colon cancer, type II diabetes, obesity
113
What are factors that enhance calcium absorption
-stomach acid and vitamin D
114
What are factors that inhibit calcium absorption
-lack of stomach acid, vitamin D deficiency, phytic acid(unleavened bread, nuts,seeds, and grains), oxalic acid(rhubarb, spinach, sweet potatoes)
115
What is the RDA range for calcium?
-700-1200mg/d
116
What is UL for calcium?
-2500 mg/d
-more can cause kidney stones. Dec. absorption of minerals, deposition of Ca in soft tissues
117
What was the effect of starvation on BMR?
-it decreased
118
What are the main functions of iron
-component in a number of of proteins
-cofactor in redox rxns and bind ligands(oxygen)
119
What are the two iron containing heme proteins and what are their functions
-hemoglobin(rbcs) and myoglobin(muscle tissue)
-oxygen transport in blood and diffusion to muscle cells
120
What are three other functions of iron
-energy, drug and alcohol metabolism
-synthesis of neurotransmitters
-immunity
121
The avg. daily western diet contains about … of iron from which only…. is absorbed
-15mg
-1-2mg
122
What is heme iron and what can it be found in?
-presents as hemoglobin and myoglobin
-beef, fish, poultry
-highly bioavailible
123
What is not heme iron and where can it be found
-plant food, dairy products, supplements
124
What are the effects of inadequate iron intake?
-iron deficiency/iron deficiency anemia
-impaired physical work performance
-delayed psychomotor development
-cognitive impairment
-adverse pregnancy outcomes
125
What is the UL for iron?
-45mg
126
What are the roles of sodium ?
-sodium-potassium pump
-co-transport in digestion and absorption
-maintains fluid balance
-maintains blood pressure
127
What are the clinical effects of inadequate intake for sodium?
-decrease in resting systolic and diastolic blood pressure
-nausea and vomiting
-decrease in urinary output
128
What is the physiological function of potassium
-nerve function, muscle contraction, fluid and electrolyte balance, blood pressure regulation
129
What are the three metabolic functions of potassium
-protein synthesis
-carbohydrate metabolism
-conversion of glucose into glycogen
130
What are the clinical effects of inadequate intake of potassium
-hypokalemia
-muscle weakness and cramping
-constipation
-fatigue
-arrhythmias and kidney stones
131
What are the main functions of magnesium?
-prevents bone loss, increased calcitonin activity
-inc. Bone resorption and crystallization, aids on parathyroid function
-uses for ATPases
-stabilizes DNA
132
What are the effects of magnesium deficiency
-hypocalcemia: low serum mg leading to low serum Ca due to induced PTH resistance, dec. sensitivity of calcium sensing receptors
-hypokalemia: mg linked with K wasting in loop of henle; essential for proper processing and transport of potassium
133
What are the main functions of phosphorus
-keeps bones and teeth strong, maintains energy levels, forms genetic material, helps form membranes of cells, keeps healthy function of brain and nervous system, helps maintain normal pH balance, helps deliver oxygen to blood
134
What are the effects of hypophosphatemia
-resorption(bones), myopathy and frailty, cardiac and respiratory failures
-loss or appetite, anemia, muscle weakness, coordination problems/neuropathy, confusion and weakened immune system
-rickets
135
What is the physiological importance of manganese
-synthesis and activation for enzymes and vitamins
-regulation of endocrine system (synthesis and secretion of insulin)
-blood clotting
-protects against free radical damage
136
Which of the following is not a way that iodine is commonly consumed in the diet, or a food commonly supplemented with iodine?
Salt
meats(beef, poultry,pork)
Seaweed
Milk
meats(beef, poultry,pork)
137
Which of the following explains the reason as to why adequate maternal iodine intake is so important for fetal development?
Without iodine, folate can’t metabolized by the fetus
Without iodine, there is an increased risk of improper hair, nail, and skin development
Without iodine, the fetus is at higher risk of stillbirth, neurological damage and intellectual impairment
Without iodine, vitamins A,D,E,K cannot be metabolized by the fetus
Without iodine, the fetus is at higher risk of stillbirth, neurological damage and intellectual impairment
138
How is manganese beneficial in the prevention of diabetes?
-Quenching reactive oxygen species
-Regulation of insulin signaling
-Regulation of glycolytic pathways
-All of the above
All of the above
139
What group of individuals lacks an upper limit (UL) for daily manganese intake?
Females aged 14-18 who are pregnant
Males aged 19-50
Infants from birth to 12 months of age
Females aged 19-50 who are pregnant
Males aged 9-13
Infants from birth to 12 months of age
140
What are the roles of zinc
Crucial for bone metabolism, regulates the immune system, nutrient absorption, regulation of blood sugar levels
141
What are the physiological/metabolic roles of chromium
-essential in breakdown of fats and carbohydrates, stimulates cholesterol synthesis, stimulates fatty acid synthesis, aids in insulin action, aids in glucose breakdown
142
What are the clinical effects of inadequate intake of chromium
-glucose intolerance, unhealthy blood lipid profiles, hyperglycemia, impaired growth, decreased fertility and longevity, insulin resistance, peripheral neuropathy, metabolic encephalopathy
143
What is the physiological importance of iodine
-normal growth, cognition and development
-required for thyroid hormone T3 and T4 synthesis, antioxidant properties
144
What is the importance of selenium in the human body?
-antioxidant and catalyst
-required for proper function of immune system
-modulate the composition of microbiota
-Key nutrient in inhibiting the development of virulence and HIV progression
145
What are the clinical effects of inadequate intake of selenium?
-cellular damage, inflammation that promotes insulin resistance, cardiovascular disease, overall metabolic dysfunction
-negatively affects normal thyroid function
146
What are the functions of copper?
-energy production (cytochrome C oxidase/complex 4)
-structural stability
-antioxidant effects
-iron transport and rbc formation
-norepinephrine production and catecholamine balance
147
What are side effects of inadequate intake of copper
-loss of energy
-weak or sensitive bones
-demyelination
-myocardial atrophy
-decreased rbc count
-anemia
148
What is the role of zinc in copper deficiency
-high zinc intake leads to an upregulation of metallothionein
-metallothionein has a high affinity for copper which leads to decreased copper entry into plasma
-copper deficiency can lead to compromised hemoglobin synthesis due to impaired ferroxidase enzymes
