Lecture 9 - Measurement of body composition Flashcards
- main storage form of energy in the body
Body fat
- sensitive to acute malnutrition
body fat
- provides indirect estimates of changes in energy balance
body fat
- most variable component of the body
body fat
how is body fat the most variable component of the body? (3)
- differing among individuals of the same sex, height, and weight
- essential fat is found on the bone marrow, CNS, and mammary glands
- storage fat is found in the inter- and intra-muscular tissues, those surrounding the gastrointestinal tract and other organs and subcutaneous fat
why do we measure body fat?
to assess undernutrition and overnutrition as well as to determine the amount of body fat and its distribution in the body
Methods of estimating body fat - Common measurements
- skin fold thickness
- body mass index
- waist circumference
- waist-to-hip circumference ratio
Newer techniques - direct, more expensive of Methods of estimating body fat
- Ultrasound
- Computed tomography (CT) Scan
- Magnetic resonance imaging (MRI)
- Provides an estimate of the size of the subcutaneous fat depot which in turn provides an estimate of the total body fat
- Most widely used method of indirectly estimating percent body fat
Skinfold thickness
What does skinfold thickness assume? (2)
- assumes that (1) thickness of subcutaneous adipose tissue reflect a constant proportion of their total body fat and (2) skinfold sites selected for measurement either singly or in combination represent the thickness of the entire subcutaneous tissue
Advantages of using skinfold thickness measurement
- Equipment needed is inexpensive and
requires little space. - Measurements are easily and quickly
obtained. - When correctly done, measurements provide
estimates of body composition that correlate
well with those from hydrostatic weighing.
Instruments for skinfold thickness measurement
- use of precision calipers
- Lange caliper
- Harpenden caliper
- Holtain caliper
give smaller skinfold thickness values
both the Harpenden and Holtain caliper
fitted with a lighter spring
Lange caliper
Where do the calipers come from?
- Lange caliper - US
- Harpenden and Holtain - Great Britain and Europe
What caliper did the MGRS which produced the WHO child growth standards use?
Harpenden caliper
Skinfold thickness sites
- most used are the tricep, subscapula, and suprailiac skinfolds
- measured at the midpoint of the back of the upper arm
Triceps skinfold thickness measurement
- measured below and laterally to the angle of the left shoulder blade with the shoulder and arm relaxed
Subscapular skinfold thickness measurement
- measured in the mid auxiliary line immediately superior to the iliac breast
Suprailiac skinfold thickness measurement
Limitations of using a single skinfold thickness measurement (3)
- Large inter-individual differences exist in fat distribution
- 2. As total body fat changes, each skinfold site responds differently
- 3. Relationship between skinfold thickness and total body fat is complex
- Large inter-individual differences exist in fat distribution
- provides the most useful population-level measure of obesity
BMI
defined as the excessive fat or abnormal fat accumulation in the adipose tissues to the extent that health may be impaired
OBESITY
- used to estimate prevalence of obesity and the risk associated with it
- correlates with the amount of body fat but it does not directly measure body fat
- not a real measure of obesity but we do not have any other tool
BMI
Classification of nut. status among adults based on BMI
(Recite the table)
Convenient and simple measurement that is unrelated to height
Waist Circumference
Correlates closely with BMI and WHR
Waist Circumference
Approximate index of intra-abdominal fat mass and total body fat
WC
Changes in _____ reflect changes in risk factors for CVD and other forms of chronic diseases
WC
- preferred anthropometric measurement for the assessment of abdominal fat
WC
Suggested waist circumference cut off points
(recite the table)
Method for distinguishing between fatness in the lower trunk and fatness in the upper trunk
WHR
- more typical for females
- associated with chronic degenerative diseases
- lower trunk fatness or lower waist-hip ratio is often referred to as Gynoid Obesity
- more characteristic of males
- associated with cardiovascular risk factors of the metabolic syndrome namely type 2 diabetes, impaired glucose tolerance, hypertension and dyslipidemia
- upper trunk or central fatness or higher waist-hip ratio is called Android Obesity
- important to classify obesity based on its distribution to permit meaningful comparisons of weight status between and within population (3)
- to enable the identification of individuals with increased risk of morbidity and mortality
- to allow priorities to be identified for intervention at individual and community levels
- to provide a firm basis for the evaluation of interventions
Suggested waist-hip circum. ratio cut off points
(Recite the table)
- composed of skeletal and non-skeletal muscles, soft lean tissues & skeleton
FFM
- body muscle serves as an index of ______
protein reserves
- very useful in determining chronic undernutrition that results to muscle wasting
FFM
Measures of FFM
- Mid-upper arm circum
- Mid-upper arm muscle circum
- Mid-upper arm muscle area
- (1) only mid-upper arm circumference must be measured
- (2) and (3) are computed using a formula
- Reflects either a reduction in muscle mass, in subcutaneous tissue or both
Mid-upper arm circumference (MUAC)
- Taken at the midpoint between the acromial process of the scapula and olecranon process of the ulna
MUAC
Uses of MUAC in nutritional anthropometry (3)
- diagnose protein-energy malnut.
- detect changes in muscle mass
- since small changes in MUAC tend to parallel changes in muscle mass; protein nawawala rin (wala nang makuhaan na ibang energy source)
- monitor progress during nutritional therapy
- bc it correlates positively with changes in weight
Instruments for MUAC measurement
- regular tape measure
- specially designed insertion tape
Mid-upper arm muscle circum
Represents the inner circle of muscle mass surrounding a small central core of bone
Used to assess total muscle mass and changes in total muscle mass
MUAMC
- provides a more valid index of body muscle mass than mid-upper arm muscle circum
Mid-upper arm muscle area
