JIMMA UNIVERSITY
PUBLIC HEALTH FACULTY
DEPARTMENT OF HUMAN NUTRITION & DIETETICS
COURSE: ADVANCED NUTRITION AND METABOLISM
TOPIC: BODY COMPOSITION
BY: HUMAN NUTRION STUDENTS (MSc)
1ST YEAR REGULAR, BATCH 2022/23
GROUP IV
1
Body composition by Group 4

GROUP MEMBER DEP’T
1. DESALEGN MEKONEN….…H. Nutrition
2. KERIMA MOHAMMED……..H. Nutrition
3. GELAYE JIBAT……….…..….H. Nutrition
2
Body composition by Group 4

 Objectives of the presentation
 Introduction to Body composition
 Levels of Body composition
 Multi-component models of Body composition
 Assessment Methods of Body composition
 Factors Influencing Body composition
 Summary of the topic.
3
Body composition byGroup 4

Learning Objectives
4
At the end of this session students will be able to:
 Define Body composition
 Discuss factors influencing body composition
 Describe levels of body composition
 Understand models of body composition
 Discuss assessment methods of body composition
 Discuss abnormalities related to body composition
Body composition by Group 4

BODY COMPOSITION
• Body composition refers to the relative percentage of
fat, muscle, bone, and other tissues in the body.
• It reflects net lifetime accumulation of nutrients by
the body.
• After birth, nutrition and lifestyle factors will strongly
interact with the genome to influence the changes in
body composition at different stages of growth
(infancy, childhood, and adolescence).
• There are different ways, levels and models to
describe body compositions.
Body composition by Group 4 5

How Do Body Weight and Body Composition
Differ?
 Body Composition
– The relative amounts of lean tissue and fat tissue
in the body
 Lean Body Mass
– Body mass that is fat-free (muscle, skin, bone,
organs, and body fluids)
 Fat Mass
– Body mass that is fat tissue (adipose tissue)
Percent Body Fat
-Percentage of total weight that is fat tissue
Body composition by Group 4 6

Fat-Free Body Mass (FFM):
 Defined as body mass devoid of all extractable fat.
Example
Body mass = 80 kg and Body fat = 24%, so what is
the FFM for this person?
 Fat mass = Body mass * % body fat
 FFM = Body mass - fat mass
Answer: 60.8 kg
Body composition by Group 4 7

Most Body Fat Is Stored in Adipose Tissue
Two types of fat make up total body fat
• Essential fat
- Found in bone marrow, heart, lungs, liver, spleen,
kidneys, intestines, muscles, and central nervous system
- Women have 4 times more essential fat than men
• Stored fat
- Found in adipose tissue
- Subcutaneous fat – located under the skin
- Visceral fat – stored around the organs in the abdominal
area

LEVELS OF BODY COMPOSITION
The composition of the body can be evaluated at
numerous level of biological complexity, from basic
elements, molecule to whole tissue compartment of
human body.
The central to body composition is the five level
model in which body mass is considered as the sum
of all components at each of the five levels:
 Atomic,
 Molecular,
 Cellular,
 Tissue-organ and
 Whole body
Body composition by Group 4 9

LEVELS OF BODY…cont
1. Atomic Level
 At this level, body mass includes 11 major elements.
 More than 96% of body mass is accounted for by the
four elements: O2, C, H and N.
 Other key elements comprise Ca2+, P, S, K, Na, Cl
and Mg2+.
2. Molecular Level
 The molecular level consists of six major
components: water, lipid, protein, carbohydrates,
bone density and soft tissue minerals.
Body composition by Group 4 10

LEVELS OF BODY…cont
3. Cellular level
 The cellular level includes three body components:
cells, extracellular fluids and extracellular solids.
 The cells can be additionally partitioned into two
components: body cell mass and fat, of which the
former is the metabolically active component.
4. Tissue-organ level
This level focuses on contribution of specific tissue to
body weight. The major components are adipose
tissue, skeletal muscle, visceral organs and bone.
Body composition by Group 4 11

LEVELS OF BODY…cont
5. Whole-body level
 It can be divided into regions such as:
 Appendages,
 Trunk and
 Head,
 Usually described by anthropometric measures such
as circumference, skinfold and length.
Body composition by Group 4 12

Different Levels of BC Measurement

MULTI-COMPONENT MODELS OF
BODY COMPOSITION
A. One compartment model: Body Weight
B. Two compartment model:
 The widely applicable 2-C model, divides the body into
two compartments:
a) fat mass (FM) and
b) fat free mass (FFM).
 The absolute amount of body fat termed, FM is the ether-
extractable lipid from adipose and other tissues.
 FFM representing the residual body compartment is
heterogeneous and includes skeletal muscle, organs, bone
and supporting tissues.
Body composition by Group 4 14

MODELS OF BODY…cont
 The model is expressed as:
 Body weight = FM+FFM
 The two-compartment models assume that:
a) The densities of the fat (0.9007 g/cm3) and fat free
(1.100 g/cm3) components are constant.
b) The proportion of water, mineral and protein in the
FFM are constant within and between individuals.
c) Individuals are similar in composition except for
variability in the proportion of fat.
Body composition by Group 4 15

MODELS OF BODY…cont
1. Hydro-densitometry
2. ADP
3. Hydrometry
Body composition by Group 4 16
Assessment methods

MODELS OF BODY…cont
C. Three-compartment model: DEXA
 This includes fat mass but partitions FFM into
total body water (TBW) and fat free dry
mass predominantly protein and mineral.
 This model provided some improvement over the
basic 2-C model for healthy individuals.
 However, for patients with significantly depleted
body protein mass and bone mineral mass, the
estimated values for the density for the solids
compartment would be incorrect; thus the final
estimate of body fat mass.
Body composition by Group 4 17

MODELS OF BODY…cont
D. Four-compartment (4C) model:
This 4Capproach divides the body into fat, water,
mineral and protein component, thereby
eliminating the need to make assumptions about the
relative proportion of these constituents in the body.
Body composition by Group 4 18

MODELS OF BODY…cont
FAT MASS
Mineral
Protein
Water
Body
Weight
4/1/2023 Melese.S 19
4 –
Compartm
ent Model
FAT-FREE
MASS

MODELS OF BODY…cont
E. Six-compartment model: NAA
Atomic model require the direct analysis of the
chemical component of the body in Vivo.
One such atomic (6-C) six component model divides
the body into the following compartments: water +
nitrogen+ calcium+ potassium+ sodium+ chloride
Although atomic model provide criterion body
composition measure for evaluating accuracy of other
reference model, the high expanse and client
exposure to radiation limit their use.
Body composition by Group 4 20

ASSESSMENT OF BODY
COMPOSITION
1.Densitometry: procedure of estimating body compo...
 The body density (Db) is equivalent to the ratio of its
mass (MA) and volume (V): Db=MA/V
 It is inversely related to body fat content- the greater
the proportion of fat, the lower the body density.
 Thus, the body density permits an estimate of
percentage of body weight that is fat.
 It involves the following methods:
i. Hydro-densitometry or Under Water Weighing
(UWW): Archimedes' principle: BV=(Wa-
Ww)/Dw
ii. Air Displacement Plethysmography: alternative
Body composition by Group 4 21

ASSESSMENT OF BODY…cont
Body composition by Group 4 22

ASSESSMENT OF BODY…cont
Body composition by Group 4 23

ASSESSMENT OF BODY…cont
2. Hydrometry:
 Water constitutes the highest fraction of body mass.
 In healthy adults, total body water (TBW) comprises
73% of the FFM or 60% of body weight.
 A 15% reduction in body water attributable to
dehydration, leads to remarkable change in body
weight and can significantly be life-threatening. This
emphasizes on determination of TBW, as an aspect of
body composition.
Body composition by Group 4 24

ASSESSMENT OF BODY…cont
 Hydrometry is based on dilution principle, which asserts
that the volume of a compartment is equal to the ratio of
the dose of tracer, administered orally or intravenously, to
its concentration in that compartment within a specified
time after the administration of the dose.
 Inherent to dilution technique there are four basic
assumptions:
i. The tracer is distributed only in the body water,
ii. It is equally distributed in all anatomical water
compartments,
iii. The rate of equilibration of the tracer is rapid, and
iv. Neither the tracer nor body water is metabolized during
the time of tracer equilibration.
Body composition by Group 4 25

ASSESSMENT OF BODY…cont
 The tracer most regularly used is non-radioactive
bromine (Br) and
 The sampling is restricted to blood plasma due to
differences in bromide concentrations in different
fluids.
 The stable isotopes commonly used are D2O and 18O.
 Body fluid samples either of saliva, urine or blood
(preferable) is collected.
Body composition by Group 4 26

ASSESSMENT OF BODY…cont
3. Whole Body Count:
 Total body potassium
 Neutron activation analysis (NAA):
4. Dual Energy X-ray Absorptiometry Method
(DEXA):
 The DEXA is linked to computer algorithms to derive
estimate of three body components:
i. bone mineral,
ii. fat-free soft tissue and
iii. fat tissue content of the total body.
 It allows fat distribution throughout the entire body to
be read in a single scan.
Body composition by Group 4 27

A DXA Machine
Body composition by Group 4

DXA Body Fat X-ray
Body composition by Group 4

ASSESSMENT OF BODY…cont
5. Bioelectrical Impedance Analysis (BIA):
It uses a very small electrical signal to measure body
impedance.
Fat causes impedance or resistance to the signal.
Rapid, non-invasive, and inexpensive method of
measuring body comp.
Sends electrical current through the body to estimate
body fat (based on the principle that fat is less
conductive than lean tissue)
Body composition by Group 4 30

BIA electrodes
Body composition by Group 4 31

Bioelectrical Impedance Analysis (BIA):
Adipocyte Impedance FFM Impedance
Body composition by Group 4 32

ASSESSMENT OF BODY…cont
6. Imaging Methods:
 Computed Tomography (CT): uses ionizing radiation.
 Magnetic Resonance Imaging (MRI): based on the
interaction between hydrogen nuclei (protons), which
are abundant in all biological tissues, and the
magnetic fields generated
 A major advantage of MRI over CT is lack of
ionizing radiation.
 So application of multiple image protocol using MRI
is the method of choice for whole-body and serial
measurements.
Body composition by Group 4 33

Computed Tomography (CT):
Body composition by Group 4 34

ASSESSMENT OF BODY…cont
7. Anthropometry:
Anthropometry provides simple approach to body
composition.
The equipment are portable and relatively
inexpensive,
procedures are non-invasive.
Anthropometric measurements such as:
 thickness of skinfolds,
 circumferences and
 diameters are frequently used to predict body density,
body fat and lean body mass by regression equations.
Body composition by Group 4 35

ASSESSMENT OF BODY…cont
7.1 Weight/height indices:
a) Quetelet index or body mass index (BMI:
weight/height2),
b) Broca index [weight/ (height - 100)], and
c) Benn index (weight/heightp, in which the exponent p
is population)
 The Quetelet index or BMI is the most widely used
index and has been recommended by WHO as a crude
indicator of the nutritional status.
Body composition by Group 4 36

ASSESSMENT OF BODY…cont
 It is used as adiposity marker in identifying
individuals at risk of metabolic disorders.
 However, its utilization has been debated as a
consequence of inability to distinguish fat mass
from fat free mass.
Body composition by Group 4 37

ASSESSMENT OF BODY…cont
Body composition by Group 4 38

ASSESSMENT OF BODY…cont
7.2 Skinfolds thickness:
Skinfolds thickness is discriminant indicators of body
fatness.
Despite relatively strong correlation of skinfold
thickness at single site with body fat % (%BF), no
single site is accurate predictor of %BF.
A special instrument called a caliper is used to
measure skinfold thickness.
Body composition by Group 4 39

ASSESSMENT OF BODY…cont
The most often measured skinfolds for the assessment
of total body fat are:
 biceps,
 triceps,
 subscapular,
 abdomen and
 supra-iliac.
Body composition by Group 4 40

Fat fold measures/Skinfold Measurements
Measuring Skinfold Fat Thickness
at the Triceps Skinfold Site Body composition by Group 4 41

ASSESSMENT OF BODY…cont
Skinfold-thickness measurements were converted into
%BF by using published regression equations.
The predicted body density can be used to derive
%BF by using a Siri's equation or underwater
weighing.
FFM and FM were then calculated from percentage
body fat and body weight.
Body composition by Group 4 42

ASSESSMENT OF BODY…cont
7.3. Circumferences and Breadths:
 MUAC, in combination with the triceps skinfold
thickness, provide an estimate of muscle mass and fat
mass of the upper arm.
 These measures correlate well with whole body FM
and FFM.
 Total body FM, FFM and %BF can be estimated
using anthropometric prediction equations derived
from healthy population
Body composition by Group 4 43

ASSESSMENT OF BODY…cont
7.4. Waist-to-Hip ratio:
 Circumference of the waist divided by circumference
of hip
 Quick measure of fat distribution
 WHO advise that a healthy WHR is:
 Women ≤0.85
 Men ≤0.9
Summary of Asst Methods.docx
Body composition by Group 4 44

Body composition by Group 4 45

Factors Influencing Body
composition:
 Diet
 Physical activity
 Age
 Gender
 Genetics/Race
 Hormonal status
 Poor sleep and stress
Body composition by Group 4 46

What is public health importance
measuring body composition?
Assessing the effectiveness of nutritional
interventions
Monitoring the changes associated with growth
Monitoring the changes associated with disease
conditions.
Nutritional evaluation in infant and children
(Commonly used for infants and children are:
Anthropometry, ADP, BIA, DEXA, MRI and Isotope
dilution)
Body composition by Group 4 47

CONCLUSION
Body composition assessment involves quantification
of the amount and relative proportions of fat, muscle
and bone, and their chemical components.
It determines the nutritional status of an individual,
consequently the nutrient requirements appropriate
for growth and maintenance of body.
All methods encompass varying degrees of inherent
deviations in measurements that are due to natural
biological or clinical variance, or measurement errors.
ADP is the Gold-Standard to assess body
composition at this time.
Body composition by Group 4 48

CONCLUSION
Methods should be chosen considering the
following:
 Level of accuracy
 Cost,
 Time
 Inconvenience,
 Radiation exposure (risk)
 Feasibility
 Availability of reference data
 Developmental stage of the subjects involved.
Body composition by Group 4 49

Here are just some of the benefits of having a
healthy body composition:
 Normal blood pressure level
 Improved quality of sleep
 Improved mood and self-confidence
 Increased energy and endurance throughout the day
 Reduced pain in joints, hips, and lower back
 Improved blood circulation — leading to lower risk
for heart disease
 Higher fertility rates and lower risk for pregnancy-
related complications
 Improved breathing, respiration, and lung function
 Improved glucose tolerance and insulin sensitivity
Body composition by Group 4 50

Male:
“Apple”
Android
Upper body
obesity
Associated:
Heart
Disease
Stroke
High BP
Diabetes
Female:
“Pear”
Gynoid
Lower body
obesity
Not usually
associated
with chronic
diseases
Body composition by Group 4 51

Health Risks Associated with Body Weight and
Body Composition
Being underweight increases health risks:
Malnutrition and disease
Anemia,
osteoporosis and bone fractures, heart irregularities,
and amenorrhea
Correlated with depression and anxiety,
inability to fight infection,
trouble regulating body temperature,
decreased muscle strength, and
risk of premature death

Health Risks Associated with Body Weight
and Body Composition
Being overweight increases health risks:
 CVD, HTN, stroke, hyperlipidemia, gallstones, sleep
apnea, and reproductive problems
 ↑es risk of certain cancers including colon, breast,
endometrial, and gallbladder cancer
 More than 80% of people with type 2 diabetes are
overweight
 Metabolic syndrome is associated with central obesity

Body composition byGroup 4 55