Body Composition Measurement Flashcards
Components of nutritional assessment
ABCDEF
Anthropometry and body composition
Biochemical
Clinical
Dietary
Environmental
Functional
Nutritional status vs nutritional risk
Status: condition of body’s nutrient stores based on intake, absorption and metabolism considering physiological needs and disease factors
Risk: risk of having nutrition-related health problems from dietary or pathology-related influences
Screening vs assessment
Screening: process to identify characteristics known to be associated with nutritional risk quickly, cost effective, valid and reliable
Assessment: systematic method of obtaining, verifying and interpreting data to determine nutritional status
(plus nutritional problems, causes and significance)
ABCDEF
Goals and Components of nutritional screening
Goals: identify, baseline for monitoring/evaluation, disease prevention, identification of specific deficiencies and malnutrition
Components:
1) Involuntary weight loss
2) Dietary intake based on appetite, dietary restrictions, intolerances and route of feeding
3) Pre-existing conditions –> nutrient loss
Ex. diarrhea or malabsorption
4) Increased nutrient requirements: inflammation, burns, fever, sepsis, injury
Why do nutritional assessment?
Hospital length of stay
Use of health care services and costs
Morbidity = having a disease or symptom of a disease (things going wrong)
Mortality = occurrence of death
Occurs in more than 50% of hospitalized patients
Stages of development of a nutritional deficiency and methods used to identify it
Dietary inadequacy - Dietary
↓ tissue reserve - biochemical
↓ bodily fluid level - biochemical
↓ function or tissue - biochemical or anthropometric
↓ enzyme activity - biochemical
Functional change - behavioral or psychological (ex. fatigue)
Clinical symptoms - clinical (appearance)
Anatomical signs - clinical (ex. hair loss)
Anthropometry components
Anthropometry: Assessment in triplicate of body size, weight and proportions using height, weight, circumferences, skinfold and ratios
Used to estimate nutritional status NOT specific nutrient deficiencies
Body composition assesses body compartments
Body composition proportions
Body total protein
Much more energy stored in fat for the same percent of body composition
Fat (25%), skeleton/skin (10%), extracellular water (25%), plasma/viscera/skeletal muscle (40%)
About 50% in skeletal muscle, then skeleton/skin, viscera and a little plasma proteins (12kg in a 70kg man)
Measuring height or Frame
Stadiometer: standing height, barefoot, level Frankfurt plane
Knee height: using knee height calipers if unable to stand
Arm span: if unable to stand straight but not for asians/African descent or spinal deformities (not recommended)
Frame size: height (cm)/wrist circumference (cm) (or elbow breadth)
For interpreting muscle area percentiles
Body weight measurement considerations
Scales: standing, chair or bed
Timing and hydration status matters
Cannot account for body composition
Amputation considerations: for estimated “whole” body weight
(body weight)/ (100-percent lost in amputation)
BMI categories for under and over 65
BMI limitations
kg/m^2
Under 65 yo
Underweight = <18.5
Healthy = 18.5-24.9
Overweight = 25-29.9
Obesity grade I = 30-34.9
Obesity grade II = 35-39.9
Extreme obesity grade III = > 40
Over 65 yo
<24 may be associated with health problems
Healthy = 24-29
> 29 associated w/ risk
Limitations: no body comp, varies with age/sex/ethnicity, athletes limited, requires other measurements but only validated method for estimating healthy BW
How to calculate healthy body weight
How to calculate UBW and ranges for malnutrition
How to calculate % weight change
Healthy BMI (high range for obese, low range for underweight) x height^2
Usual body weight = (current/usual) x 100
85-95% –> mild malnutrition
75-84% –> moderate malnutrition
<74% –> severe malnutrition
% change = (UBW - current weight)/UBW x 100
Know 5% in 1 month or 10% in 6 months for significant and more is severe
*Clinically relevant to predict nutritional risk and health complications
Risks with involuntary weight loss
Loss of fat and fat-free mass can predict: mortality, surgical/post-op complications, frailty, malnutrition and risk of functional impairment
Skinfold thickness
Measures subcutaneous adipose tissue content and assumes representativeness of each site for whole body
Skinfold calipers to measure biceps, triceps (most common), subscapular and suprailiac
Mid arm site measurements
TSF and MAC and MAMA/cMAMA
MAC: mid-upper arm circumference reflects muscle/bone/fat - not sensitive
MAMC = MAC (mm) - (π x TSF)
insensitive to small changes in muscle but corrects for fat
MAMA = MAMC^2/4π
More accurate total body muscle mass but insensitive to small change
Less valid in elderly or obese
Includes bone –> cMAMA = MAMA - 10 (men) or MAMA - 6.5 (women)
MAFA = sub-cutaneous adipose measurement
