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1
Q

how much energy is used as heat

A

Gross Nrg: total available nrg (chem nrg) in food
Net Nrg: nrg available to the animal after metabolic
processes of digestion, absorption, excretion
• animal will use some nrg for heat (about 55-60%)
• animal will capture rest to nrg in high-nrg phosphate
bond (eg, ATP, creatine phosphate, phosphoenol
pyruvate) which eventually is liberated mainly as heat

2
Q

• Digestible Energy (DE)

A

– DE in monogastrics = GE - fecal energy (BC)

3
Q

The Respiratory Quotient (RQ)

The Respiratory Quotient (RQ)

A

ratio of CO2 produced : O2 consumed
- can be calculated using either the volumes or mols of O2 and CO2
Use of Biological Oxidation Data:
1. Determine, from O2 consumption, EE of an animal
(ie,Metabolizable Energy Expenditure)
2. If RQ is close to 0.7, can predict FAs are main fuel being [O]
- never be quite as low as 0.7; “obligate glu users”
3. If RQ is close to 1.0, can predict glu (hence CHO) is the main
physiological fuel being [O]
4. If RQ is between 0.7 - 1.0, you cannot predict, with this data
alone, the “mix” of fuel being [O]

4
Q

Estimated Energy Requirement

EER

A

A level of dietary energy intake sufficient to
maintain a stable healthy body weight and an
adequate level of physical activity
• Differs from EAR in that it is not a distribution
of intakes (bell curve) reflecting physiological
variability

5
Q

• Resting Metabolic Rate (RMR):

A

energy
expenditure under resting conditions. Somewhat
higher than BMR due to recent food intake or
recent activity.

6
Q

Total Energy Expenditure (TEE):

A

sum of basal
energy expenditure, thermic effect of food,
physical activity, thermoregulation, and energy
expended in depositing new tissues and
producing milk (lactation).

7
Q

Energy Intake is mesureed by

A

Food Freq. Quest. (FFQ)
• 24h Recall
• Food Records
• Food Weighin

8
Q

Energy Expenditure

A
Direct Calorimetry
• Indirect Calorimetry
• Heart Rate Monitoring
• Estimated from Activity
– Motion sensors
– Activity diary
– Direct observation
• Doubly labeled water (D2
18O)
9
Q

Selection of Indicators for Estimating

Energy Requirement

A
  1. Reported Energy Intake
    • Reported energy intakes of weight-stable
    individuals could be used to predict energy
    requirements for weight maintenance
    • Limitation: reported energy intakes in dietary
    surveys underestimate usual intake (can range
    from 10-45% below actual intake)
  2. Factorial Approach
    • Used to set previous RDA
    • Calculates TEE using activity info in 24 h period
    and energy costs of each activity
    • Limitation: not feasible to measure energy cost
    of all ADLs
    • Factorial method may underestimate energy
    needs
    Selection of Indicators for Estimating
    Energy Requirement
  3. Measurement of EE by Doubly Labeled Water (DLW)
    • Used to set EER
    • Relatively new technique in humans
    – However, proposed and developed by Lifson (1950-1960s) for use in
    small animals
    • Adapted and now extensively used in humans (Schoeller et al.,
    1986)
    • Uses stable isotopes H2
    18O and 2H2O

    2H2O relates to water flux
    – H2
    18O relates to water flux plus carbon dioxide production
    – These isotopes also can be used independently to measure TBW using
    the principles of dilution
10
Q

DLW Approach

A

Subject drinks known amount of the 2 stable isotopes of
water
• Isotopes mix with the body’s water
2. Sample periodically (over 3 weeks) a body fluid (i.e., urine or
blood) to measure disappearance of isotopes

2H2O is lost from the body only as water
• H2
18O is lost from the body in water and as C18O2
3. The difference between the 2 disappearance rates is an
index of body’s CO2 production
4. Predict TEE from a measurement of CO2 production
• Knowledge of composition of the diet
• Use standard indirect calorimetric techniques (RQ = ratio of
CO2 produced and O2 consumed)

11
Q

Advantages of the DLW Method

A

Allows measurement of energy output under
normal, everyday conditions
• Represents patterns of energy expenditure
over several days
• Reflects differences in BMR during the day
and night/sleep
• Includes the energy cost of all physical
activities

12
Q

DLW Database (Inclusion Criteria)

A

0-2 y wt-ht percentiles between 3rd and 97th
3-18 y BMI percentiles between 5th and 95th
>18 y BMI 18.5 – 24.9

13
Q

DLW Database (Exclusion Criteria)

A

• Studies manipulating energy intake or
expenditure
• Elite groups: soldiers, astronauts, athletes
• Individuals with a PAL > 2.5 (PAL=TEE/BEE)

14
Q

2 Compartment Model

A

body fat
– fat-free mass (FFM)
• FFM = body wt – body fat (fat mass); LBM = body wt – adipose fat
• LBM includes essential fat (e.g., cell membrane fat)
• often FFM = LBM in literature

15
Q

6 Compartment Chemical Model (Brozek et al. 1963)

A
– aqueous - includes ECW, ICW
– mineral - osseous
 - extraosseous
– organic - glycogen (negligible)
 - protein
 - fat
16
Q

Elemental Model

A

body weight consists of 11 elements which comprise >99% of body
weight in living subjects
i.e., C, N, Ca, Na, Cl, K, H, P, O, S, Mg

17
Q

why is weight usefull

A
Weight
• Useful for extremes
– 300 lbs or 80 lbs for an adult female
– 140 lbs ???
• Monitoring change
– sudden gains or losses in weight
18
Q

why is height usefull

A

Height
• Useful for “stunting”
– indicator for undernutrition
– nutrient deficiencies e.g., Zn

19
Q

what % of weight can be accounted for by height

A

49%

20
Q

mi·cro·bi·ota

A

“a microbial community, including
bacteria, archaea, eukaryotes, and
viruses, which occupy a given
habitat”

21
Q

metagenomics

A
Metagenomics is the process used
to characterize the metagenome
(genes from microbiota), from which
information on the potential function
of the microbiota can be gained.”
22
Q

what factors shape the microbiota

A

diet, genetics, antibiotics, geography, exposure

23
Q

The Aging Microbiota

A

Themicrobiomesofolderadultsappeartoadoptapro‐inflammatorystatewithincreased
potentialforDNAdamageandimmunecompromise.

24
Q

what factors influence the microbiota

A

medication- interfears with proton pump

enviro: ex having a dog

25
Q

Inflammation (Dysbiosis)

A
can lead to leakage
The Western diet
alters the intestinal
microbiota
promoting a lowgrade
chronic
inflammation in the
gut
26
Q

probiotic

A

“Live micro-organisms that,
when administered in adequate
amounts, confer a health
benefit on the host”

27
Q

Prebiotics

A

aselectivelyfermentedingredientthat
resultsinspecificchangesinthecomposition
and/oractivityofthegastrointestinal
microflora,thusconferringbenefitstohost
health.
bananas, artichoke, garlic, asparagus— inulin
galacto oligosacharides- breast milk

28
Q

Starch

A

a) amylose: (15-20%), non-branched, α 1→4
b) amylopectin: (80-85%), branched
α 1→4 in straight chain, α 1→6 branch pt

29
Q

→ β-1,4 and α-1,6 resistant

→ α-1,4 bonds of starches

A

s

30
Q

what happens to gal fru, glucose in the liver

A
- gal + fru taken up by hepatocyte receptors
→ metabolized [energy]
→ converted to glu then glycogen
- glu enters cells by facilitated diffusion
(insulin independent)
→ metabolized [energy]
→ remainder to circulation (systemic) to
various tissues
31
Q

which transport protein is used in liver, b-cells of pancrease, kidney, small intestine,

A

GLUT2

32
Q

which transport protein is used in the muscles, heart, adipocytes

A

glut 4

33
Q

hyperglycemia cut oof

A

the level of blood glu (~10 mmol/L or ~180 mg/dL in the
human) above which the kidneys can no longer reabsorb
glu as fast as being filtered at the glomeruli

34
Q

Hypoglycemia:

A

blood glu levels below normal (< fasting blood
glu level; 5 mmol/L, 90 mg/dL)
eg, hypersecretion of insulin

35
Q

Steps in glucose oxidation

A
1. glycolysis:
glu → 2 pyruvate → (2 lactate – if anaerobic)
2. pyruvate dehydrogenase
(thiamine pyrophosphate)
pyruvate → acetyl CoA
3. TCA/Kreb’s/citric acid cycle
acetyl CoA → TCA cycle
→ 3 NADH, 1 FADH, 1 GTP
→ energy (heat, ATP)
-Most ATP is derived from oxidation of
NADH+H+ (3 ATP rounded up) and
FADH2
(2 ATP rounded up) via etransport
chain
36
Q

The PDH (pyruvate dehydrogenase) Complex

A
The complex uses five coenzymes.
• Three are prosthetic groups - covalently
bound to their enzymes.
– TPP (thiamine pyrophosphate)
– Lipoamide
– FAD
• Two are transiently associated with the
complex.
– CoA
– NAD+
/NADH
37
Q

TPP

A

TPP is the coenzyme form of the
vitamin (B-1) thiamine that functions in
the decarboxylation of α-ketoacids.

38
Q

where does the decarboxylation of pyruvate and the oxidation of acetate take place

A

in the mitochodrial matrix

39
Q

where does atp synthase take place

A

inner mito membrane

40
Q

how much energy does one glucose create

A

30

41
Q

all tissues except one have PDH and TCA capabilities except one

A

RBC

42
Q
  • each gram of glycogen is stored with -
A

3-4G h20

43
Q

each g of fat is stored with

A

0.15 g fat

44
Q

A fatty acid molecule is in a more reduced

state than a molecule of glucose.

A
Thus, more
energy is
extracted from
the oxidation of
FA than CHO.