Introductory HUMAN NUTRITION Dr. Gilang Nurdjannah, dr. Dipl

ENERGY
REQUIREMENTS
THE NEED OF ENERGY
Dr. Gilang Nurdjannah, dr.
Dipl.Nutr
Department of Nutrition
Medical Faculty, Padjadjaran University
The Calorie :
• The standard unit used to measured energy
• Used in nutrition as kilo calorie (large calorie,
written Calori (Cal)
• Is thousand times greater than small calorie
(cal) used in chemistry or physics (Robinson,
Lawler, Wilson, et all)
• 1 kilocalorie is the amont of heat required to
raise the temperature of 1 kg water 10C (from
150C to 160C)
The vital process are :
• The functional activities of the various important organs
such as the brain, heart, liver, kidneys, lungs (respiratory
system).
• The secretory activities of the glands.
• The peristaltic movements of gastrointestinal tract.
• The oxidations of resting tissues.
• The maintenance of muscular tone.
BEE (Basal Energy Expenditure) is energy
expenditure/usage of energy in basal condition,
is the ongoing activity while the body rest, i.e
heart beat, peristaltic, hormone and enzyme
secretion, muscular tone; these activities can’t
be
stopped
by
brain
command,
it’s
automatically straight forward goes on.
Three factors determine the total energy
need of an individual are :
• The basal metabolism. This is the amont of energy
required to carry on the vital processes of the body
when awake. This includes the regulation of body
temperature as an important entity in the basal
metabolism
• The physical activity
• The specific dynamic effect (action) of food. This is
extra energy required to metabolize the food, increase
in heat production
The Basal Metabolic rate is measured by
indirect calorimetric, indirect measure of
heat
production
using
Benedic-Roth
apparatus by calculating the amount of
oxygen consumed under the specific
conditions in basal conditions.
Basal Condition is the state of the
body in which :
• 12 – 16 hours after the last meal
• Lying position, awake
• No physical activity an hour before the test
• Relax - without emotional feeling
• Normal body temperature
• Room temperature should be 21-250C,
Normal humidity - comfortable
Numerous experiments on people of all ages shows 1 ltr
of O2 is equal to 4,825 Cal (kcal) in the conditions for
basal metabolic test.
Suppose a young woman consumes 1,200 cc O2 in a
6-minute test of a 24 hour period, her basal heat
expenditure is :
10 x 1,200 x 24 = 288 ltr O2 in 24 hour
1000
= 288 x 4,825 = 1,390 Cal
BM rate approximately 1 Cal/Kg/h for men and about 0.9
Cal/Kg/h for women.
The range of BMR for normal adults is 1,300 – 1,700 Cal
Fundamental points about metabolism :
• Each reaction does not occur in isolation but
provides a substrate.
• Pathways  producing a continue process.
• Metabolic map.
• Some of the reactions are one way.
• Concepts & purpose of reactions
Metabolic pathways can be classified as either
catabolic or anabolic.
Catabolism is the breakdown (degradation) of
energy-rich complex molecules :
protein  CO2, H2O, NH3
Anabolism is the synthesis of complex molecules
from simpler ones; protein from amino acids.
Catabolic pathways names end is lysis meaing to
breakdown.
Glycogenolysis  glycogen breakdown
Proteolysis  protein breakdown
Lipolysis  fatty acid breakdown
Glycolysis  glucose breakdown
Anabolic pathways names end in genesis meaning to create.
Glycogenesis  glucose synthesis, protein synthesis
Lipogenesis  fatty acid synthesis
Gluconeogenesis  glucose synthesis
The transfer of energy in reactions; when chemical bound
breaks, energy can be released as heat, captured in
another chemical bound, or both.
The site of reactions; metabolic work is going on all the
time within the cells. Catabolism of energy-rich
compound (carbohydrate, protein & fat); anaerobic
reactions in the cytosol; aerobic reactions occur in the
mitochondria.
Regulations of pathways: metabolic reactions mostly
require enzymes (or hormones) to facilitate their action.
Enzymes need coenzymes. The enzymes are subject to
strict regulation to ensure that :
• The rate of the pathway is adapted to the cell’s
needs
• Anabolic & catabolic pathways are not active at the
same time.
COMPLETE CATABOLISM
CH & lipids  CO2 + H2O + energy
Amino acids  CO2 + H2O + NH3 + energy
Production of H2O & energy in the mitochondria :
H2 + O2  H2O + energy
The energy potential produced, could form high
energy phosphate molecules (ATP & GTP)
ADP + phosphate + energy  ATP
GDP + phosphate + energy  GTP
The breakdown of high energy phosphate molecules
will occur if the cells need energy.
ATP  ADP + energy
Functions of the energy released :
• To conduct nerve impulse (electric)
• Actin & myosin contraction (mechanic)
• Transfer of molecules across membrane
(osmotic)
• Heat formation (thermic)
• Anabolism (chemic)
Each organ has a preferential fuel; the substrate
prefers to be used for energy production.
 Glucose : brain, red blood cells, adrenal gland and
muscle in anaerobic activity and high intensity of
aerobic activity
 Fatty acids : heart, liver, smooth muscle and
skeletal muscle in low intensity of aerobic activity
 Branch chain amino acids (BcAA): skeletal muscle.
 Other amino acid: liver
Result condition between energy intake and energy
expenditure determine the energy status
Energy Expenditure  Energy Intake
Energy status assessment for children  measure
weight for age
Energy status assessment for adults  weight for
height: Body Mass Index (BMI)
BW (kg)
H (m)2
Balanced equilibrium energy : if energy intake
appropriate with the energy expenditure
Surplus of energy : if energy intake larger than energy
expenditure  energy storage increase :
• CH  stored as glycogen (limited) in liver & muscle
and as lipid (abundance)
• Fat  stored as lipid.
• Protein  stored as lipid.
Daily amount of energy intake depends on : food class,
quantity per portion, and frequency of food intake per
day
Nutrient composition & amount of energy per 100 grams
food stuff are available in Food Composition List (Table).
Food stuff weight comes from Household measurement.
DAILY USAGE OF ENERGY
Total Energy Expenditure = TEE : sum of
Basal Energy Expenditure (BEE)
Physical Activity (PA)
Specific Dynamic Action of Food (SDA)
Thermic Effect of Food (TEF).
The calculation :
TEE = BEE + PA + SDA (TEF)
Harris & Benedict calculation for BEE
Men
: 66 + (13,7 x BW kg) + (5 x BH cm) – (6,8 x age)
Women : 665 + (9,6 x BW kg) + (1,7 x BH cm) – (4,7 x age)
Simple calculation for BEE (Wilson)
Men
: 1 Kkal / BW kg / h = 24 Kkal / BW kg / d
Women : 0,9 Kkal / BW kg / h = 21,6 Kkal / BW kg / d
Factors that influence BEE
Body weight, height, age, gender/sex, growth,
temperature, muscle mass, sleep, endocrine activity,
nutrition status
Age : above 20  BEE will decrease 2% every 10 year.
Gender : BEE in men > women (at age > 10 year)
Growth : highest for baby and adolescence.
Height : the taller the higher BEE.
Muscle Mass : the greater the higher BEE.
Temperature : every 100C elevation of body temperature
(above 370C)  BEE will increase 13%.
Sleep : BEE decrease 10%.
Endocrine : − hyperthyroid  BEE increase 75-100%
− hypothyroid  BEE decrease 30-40%
− right before menstruation BEE slightly
increase and during menstruation BEE
decrease
Nutrition status : BEE decrease in PEM
Pregnancy : BEE increase 12-25%
The




rate of basal metabolism is influenced by :
Body size
Shape (surface area)
Sex (women have 6-10 % lower than men)
Age (BMR is high per unit surface area in first 2
years of life)
 Activity of the endocrine glands (thyroid gland
regulates the rate of energy metabolism and any
change in thyroid activity will be reflected in the
metabolic rate : in hypothyroidism BM is reduced
30-40 %)
 Sleep (BM 10% lower than awaking state)
 Body temperature (an elevation of body
temperature above 370C will increase BM by 13%
per 0C)
Every physical activity needs energy above BMR
Energy Cost of Physical Activities
Activity
Cal/KgBW/Hour
Bicycling (fast)
7,6
Bicycling (slow)
2,5
Dancing (foxtrot)
3,8
Dancing (waltz)
3,0
Dish washing
1,0
Driving
0,9
Table tennis
4,4
Marathon run
7,0
Sawying
5,7
Walking 5 km/h
2,0
Writing
0,4
Playing piano
2,0
Sewing
0,6
Energy for Physical Activity (PA)
•
•
•
•
•
PA
PA
PA
PA
PA
very light
light
moderate
heavy
very heavy
=
=
=
=
=
10-30% BEE
30-50% BEE
50-80% BEE
80-100% BEE
> 100% BEE
Level of Activity
• Very light
• Light
• Moderate
• Heavy
• Very heavy
- Activity in sitting position, bedrest
- Teacher, lecturer, general practioner,
housewife
- Farmer, student (+sport), moderate
build worker
- Athlete during TC, unskilled worker,
manual laborer, army during training
- Sawyer of wood, blacksmith, ricksaw
carrier, becak driver
SDA or TEF
SDA / TEF is the amount of energy used for digestion,
absorption and transportation of food consumed.
• SDA of protein 30% BEE
• SDA of carbohydrate < protein
• SDA of fat  the lowest
SDA of Indonesian food on the average is 10% of BEE,
more likely (dominant) of CH
SDA of food is the amount of energy required to
digest mixed food (Carbohydrate, protein, lipid, fruit
& vegetable).
Approximately 10% of BM is required as the SDA of
food; especially in Asian’s meal/food intake more
dietary fibres contents (vegetables and fruits) daily
consumed.
60 Kg, BM = 1440 Cal 24 Cal/kg
SDA
= 144 Cal
Total
= 1584 Cal (BM+SDA)
Western people consumes less dietary fibres
 SDA : 6% - 8% of BM
It is not easy to measure factor of activity, especially in
children (due to bone growth), pregnant or lactating
women and for those who are in reconvalescence state.
Therefore FAO (1957) recommends a general reference
of men and women as follows
Reference Men
•
•
•
•
•
Age 25 y.o
Healthy
55 Kg
Lives in temperate zone (Europe)
Activity
– light activity 8 hours
– mild activity 4 hours
– walking 5 km 2 hours
• 3200 Cal/day
Reference Women
•
•
•
•
•
Age 25 y.o
Healthy
55 Kg
Lives in temperate zone (Europe)
Activity
– housework
– light individual work
• 2300 Cal/day
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