2. The first step before planning and evaluating
the nutritional care of individuals or groups
Determined on the basis of multiple kinds of
information
A systematic method for obtaining, verifying
& interpreting information
5. Four main components
1. Anthropometry
2. Biochemistry (Laboratory assessment)
3. Clinical assessment
4. Dietary intake
5. Energy requirements
6. Study of physical dimensions of the body
Standardised equipment & procedures essential
Body size
direct measurements
height, weight, circumferences
derived values
Body shape
Waist hip ratio, body weight distribution
Body composition
size of lean tissue and fat compartments
7. One of the most commonly used
measurements for assessing nutritional status
Ratio of weight to height
Caution – BMI not ideal for determining health
risk as it does not reflect amount of muscle
compared to fat
8.
9. # WHO 2000, AIHW (2004)
* Ideal body wt (IBW) or desirable wt for ht (US Metropolitan Life Insurance data)
9
Classification # BMI (kg/m2) IBW % * Risk of Chronic
Disease
Underweight <18.5 >10% below* Low (but other
risks)
Normal range 18.5-24.9 desirable Average
Overweight >25
pre-obese 25.0-29.9 (10-19% above*) Increased
obese class I 30.0-34.9 (>20% above*) Moderate
obese class II 35.0-39.9 Severe
obese class III >40 Very severe
10. BMI classification in kg/m2
10
Asian Pacific Is.
<18.5 <19.9 Underweight
18.5-23.9 20.0 - 26.9 Normal
weight
24.0-26.0 27.0-32.9 Overweight
27.0-39.0 33.0-39.9 Obesity
11. The International Obesity TaskForce
(IOTF) published BMI thresholds defining
paediatric overweight and obesity in
2000.
Centile equivalents for children aged 2–18
were derived statistically by
extrapolation from adult cutoffs at BMI 25
and 30 kg/m2, respectively.
They were not intended for clinical use
but to assess trends and to compare
populations.
12.
13.
14. Height requires a
stadiometer – a
ruler calibrated in
cm and m, which is
fixed to the wall
and has a movable
head plate
15. Infants up to 36
months should be
measured in
cm, using
recumbent length
if they are unable
to stand
16. Chumlea has developed formula to estimate
knee height in those who are unable to stand
Men = 64.19 – (0.04 X age) + (0.02 X
knee height)
Women = 84.88 – (0.24 X age) + (1.83 X
knee height)
Chumlea WC, Steinbaugh ML, Roche AF, Mukherjee D, Gopalaswamy N.
(1985) Nutritional anthropometric assessment in elderly persons 65 to 90
years of age. Journal of Nutrition for the Elderly. 4:39-51.
17.
18. Is measured on scales
which are on a hard, firm
surface and calibrated
daily
Weight is usually
measured to the nearest
0.5kg
19. 1. Waist circumference (AIHW, 2005) > 18 y
>94 cm (M) >80 cm (F) – abdominal
overweight
>102 cm (M) >88 cm (F) – abdominal
obesity
2. Waist: hip ratio
visceral fat around organs vs.
subcutaneous fat on hips
optimal WHR is < 1 (M) or < 0.8 (F)
varies with: genes, age, ethnicity, sex
increased by 'stress', smoking, alcohol
decreased by physical activity
19
21. Metabolically active tissue determines
energy requirements
Lean body mass or muscle mass is the
most metabolically active tissue
Bodies are made up of water and
fluids, bone, muscle and fat
80% of energy requirements are
determined by height, weight, sex and
age
22. Body fat – skinfold thicknesses and Dual X ray
Absorptiometry (DEXA)
Body water – Bioelectrical impedance (BIA)
Body cell mass – Total body potassium, DEXA
(bone, muscle)
28. Blood tests
Readily obtained (so often used)
Vary little (homeostatic control)
Should be used in conjunction with nutrient and
supplementation history
Tissue testing
May include hair & nails for information about
trace elements
Other tissues only acceptable under exceptional
circumstances (invasive)
Urine testing
Varies between nutrients and influenced by
variety of factors (including volume of urine)
Multiple samples required
Functional tests
Ability to perform specific functions (e.g.
muscle response, immunological response)
29. Advantages:
Provide the earliest
indications of some
nutrient deficiencies &
excesses
Can confirm a nutritional
diagnosis made on the
basis of signs & symptoms
Can be used to assess the
effect of nutritional
therapy
30. Information obtained includes:
Socio-demographic details (age, gender, occupation)
Medical history (including family history)
Dietary intakes
To help identify patients at risk of nutritional deficiency
Signs & symptoms important
32. Infant birth weight
Provides information on:
maternal health & nutritional status
risk of infant mortality
Is influenced by:
maternal body size, infection, smoking, alcohol
consumption, maternal nutrition during pregnancy
Infant mortality data
% related to prevalence of low birth weight (populations
with high rates of low birth weight usually have high
rates of infant mortality) e.g. Indigenous Australians
Also
affects
33. Inappropriate infant feeding practices influences
growth & development esp. in the 1st 4 to 6 mths
Decrease in breastfeeding since 1945 (21% 1971, above 50%
since 1985)
Breastfeeding or correctly prepared infant formula
infant morbidity & mortality
34. Provide information on:
the diseases & conditions that are reported as
causes of death/hospital admissions
possibly on chronic conditions such as cancer &
diabetes
Reflect:
the major social & health problems of the
community
And can be used as:
clues to the most likely causes of mortality &
morbidity
measures of the prevalence of specific nutrition
related conditions
35. Only provide information on:
Indirect measures of the kinds of nutritional
problems most likely to be encountered in a
population
Multi-factorial aetiology of conditions in developed
countries
Current burden of disease statistics available from
the AIHW
Disability adjusted life years (DALYs) are the years of
life lost due to premature mortality & disability &
measure the number of healthy years of life lost as a
consequence of death or newly diagnosed disease or
injury in the population.
36. Weight & height are used in population studies as
they:
provide an overall measure of nutritional status
are non-invasive
are quick to carry out
use minimal (& cheap) equipment
Provide information on:
the growth of children
the prevalence of obesity or underweight
Notes de l'éditeur
The skinfold estimation methods are based on a skinfold test, whereby a pinch of skin is precisely measured by calipers at several standardized points on the body to determine the subcutaneous fat layer thickness. These measurements are converted to an estimated body fat percentage by an equation. Some formulas require as few as three measurements, others as many as seven. The accuracy of these estimates is more dependent on a person's unique body fat distribution than on the number of sites measured. As well, it is of utmost importance to test in a precise location with a fixed pressure. Although it may not give an accurate reading of real body fat percentage, it is a reliable measure of body composition change over a period of time, provided the test is carried out by the same person with the same technique.Skinfold-based body fat estimation is sensitive to the type of caliper used, and technique. This method also only measures one type of fat: subcutaneous adipose tissue (fat under the skin). Two individuals might have nearly identical measurements at all of the skin fold sites, yet differ greatly in their body fat levels due to differences in other body fat deposits such as visceral adipose tissue: fat in the abdominal cavity. Some models partially address this problem by including age as a variable in the statistics and the resulting formula. Older individuals are found to have a lower body density for the same skinfoldmeasurements, which is assumed to signify a higher body fat percentage. However, older, highly athletic individuals might not fit this assumption, causing the formulas to underestimate their body densityAdvantages: simple, quickDisadvantages: requires training, 5 – 10% error
The general principle behind BIA: two conductors are attached to a person's body and a small electric current is sent through the body. The resistance between the conductors will provide a measure of body fat, since the resistance to electricity varies between adipose, muscular and skeletal tissue. Fat-free mass (muscles) is a good conductor as it contains a large amount of water (approximately 73%) and electrolytes, while fat is anhydrous and a poor conductor of electric current.Advantages: simple to useDisadvantages: Altered hydration status will affect results
Dual energy X-ray absorptiometry, or DXA (formerly DEXA), is a newer method for estimating body fat percentage, and is a very efficient and advantageous method of determining body composition and bone mineral density.X-rays of two different energies are used to scan the body, one of which is absorbed more strongly by fat than the other. A computer can subtract one image from the other, and the difference indicates the amount of fat relative to other tissues at each point. A sum over the entire image enables calculation of the overall body compositionAdvantages: High precision, measures fat directlyDisadvantages: Expensive
Whole body counting, refers to the measurement of radioactivity within the human body. The technique is only applicable to radioactive material that emit gamma rays. A gamma ray is emitted from a radioactive element within the human body. If its energy is sufficient that it can escape the body before being absorbed or have any other interaction where it can lose energy, it can be detected. Usually either a scintillation detector or a semiconductor detector would be used for such purposes.There are many ways a person can be positioned for this measurement: sitting, lying, standing. The detectors can be single or multiple and can either be stationary or moving.Advantages: Direct measure of intracellular K, 3 – 4% errorDisadvantages: Availability and expense (research only)
