Nutritional Assessment Flashcards
Screening
Definition
purpose
instruments
Screening: process of identifying characteristics known to be associated with nutritional problems
Purpose is to quickly identify individuals with nutritional risks –Should be easy to use, cost effective, valid, reliable, sensitive
Goal: identify individuals who might have nutritional problems, without knowing if they have them already or not
Tool: should be rapid, easy and cost-effective. Ideally- reliable, sensitive and verifiable Such a tool doesn’t exist as nothing is perfect
Assessment Definition
process of assessment of body compartments and analysis of structure and function of organ systems and their effects on metabolism
– Most often performed by dietitian
– Includes medical and dietary history, physical examination, anthropometric measurements and analysis of biochemical and functional status. Subjective and objective data
Goals of nutritional assessment
- To identify patients needing nutritional support
- To use as a baseline for monitoring and evaluating the response to our nutritional intervention plan For:
- Disease prevention
- Identify specific deficiencies and/or
- Overall malnutrition
Where is malnutrition occurrence is the most frequent?
Malnutrition is the highest at long-term care facilities It develops during the hospital stay
Why do we assess for malnutrition?
Malnutrition is associated with increased:
– Morbidity (above and beyond the disease state)
– Mortality
– Hospital length of stay
– Use of health care services and costs Malnutrition affects more than 50% of hospitalized patients
What are the 4 components we screen for during initial nutritional screening?
1) Pre-existing conditions causing nutrient loss - Malabsorption, diarrhea
2) Conditions that increase nutrient requirements - Fever, burns, sepsis, injury
3) Dietary Intake - Appetite adequate? Dietary restrictions? Intolerances? Route of feeding (oral, enteral, TPN)?
4) Weight loss
How do we assess? aka what ascpects do we look at
- Anthropometrics
- Biochemical
- Clinical - includes physical examination, and Hx
- Dietary
- Functional
Describe anthropometric data
- Established criteria (BMI) - NHANES I and II reference tables - Nutrition Canada reference tables
• <5th and >95th percentile suggest nutritional risk
Describe biochemical data
- Cut-off values, normal lab values (differ by institution) e.g. blood test, but urine, saliva etc can also be used lab values differ b/w institutions
subjective vs objective data
subjective data- affected by human factor objective data- cut clear, cannot be influenced by human factors e.g lab test
describe clinical data
- Physical signs and changes (i.e. presence or absence of edema) this data can be collected without performing any specific tests, just by looking
describe dietary data
- DRIs - harmonization of U.S. and Canada - Canada: Canadian Food Guide on Healthy Eatingànew in 2019 - U.S.: USDA food pyramidàDietary Guidelines 2016
Development of a nutritional deficiency describe stages and method used for analysis
- Tissue reserve of that nutrient will decrease. Sometimes we can measure that, sometimes we can’t e.g. vitamin A storage levels in the liver cannot be measure as it is too invasive. Some nutrients, however, can have markers e.g. ferritin is a marker of iron levels stage
5- Some nutrients are co-factors, hence the decrease in enzyme activity e.g. decrease in urea cycle in protein deficiency stages 6-8 can be observed without performing any tests-> these are the stages when the deficiency is severe
Anthropometry vs body composition
Anthropometry = body size, weight and proportions Body Composition = body compartments
What are the 2 body compartment system.? 3 compartment system?
2 major compartments: fat mass and fat free mass or 3: bone, fat and fat-free mass
What can anthropometry be used for? Cannot be used for?
- Allow to assess body size and composition using:
- Height, weight, circumferences, skinfolds, ratio
- Used to estimate nutritional status and evaluate intervention
- Body composition correlates with function
- Measurements to be done in triplicates
NOT to identify specific nutrient deficiencies
WHat are the components (%) of the body
25% - skeletal muscle
15%- viscera
5%- plasma proteins
15%- extracelular
10%- skeleton, skin
25%- fat
__ % of lean mass is water
73 % of lean mass is water
Does fat store water?
no
WHat are the methods of measuring skeletal muscle?
Arm muscle circumference (MAMC) Creatinine Height Index (CHI)
what are the markers of viscera functioning?
Albumin, TTR, RBP
What are the ways of measuring fat % in our body
Skinfold thickness Waist circumference
What are the ways of measuring height?
Standing Knee hight Arm span
describe standing method of measuring height
using a stadiometer (barefoot, heels and shoulders touching the wall, Frankfurt plane) the head should be placed according to the Frankfurt plane- line should be parallel to the floor
describe knee height method of measuring height
- If unable to stand (equations by age, sex and race p.50, Nelms) using callipers with person lying on the be, 90 degree angle at the knee. Measure form the knee to the bottom of the heel Put the measurement into the equation
describe arm span method of measuring height
nor recommended - unable to stand straight - not for Asians, African Americans, spinal deformities
Describe wrist circumference measure
used as a ratio
r = height (cm) / wrist circumference (cm)
Describe amputation adjustments
- head- 7%
- forearm- 2.3%
- wrist- 0.8%
- whole arm- 6.5%
- whole leg- 18.6%
- bottom part of the leg- 7.1%
- foot- 1.8%
Example: current weight 70 kg with arm amputation Estimated body weight: 70 kg/ (100%-6.5%) = 74.9 kg
BMI formula
Body Mass Index = weight (kg) / height2 (m2)
How does “normal” bmi differ for adult less and more than 65 years
healthy BMI for adults >65 y.o is higher
<65 y.o 18.5-24.9 Healthy
>65 y.o 24.0-29.0 Healthy weight for most elderly
What are the BMI limitations
• Does not measure body composition • Varies in relation to age, sex, ethnicity • Limited applicability in athletes • Must be accompanied by other measures, i.e. waist circumference
Which BMI group is the highest to evaluate?
>30
What is the only method for evaluating healthy body weight
BMI
How to calculate target healthy body weight
current height: 1.70 m, weight: 105 kg, BMI= 30.9 kg/m2 Target or reasonable weight: 25 x 1.702 = 72 kg
don’t tell the patient the target __, tell them the target __
don’t tell the patient the target BMI, tell them the target weight
How to calculate % UBW
% usual body weight (UBW) % UBW = (current weight / usual BW) x 100
How to calculate % weight change
% change = (UBW – current weight)/ UBW
Interpretation of % weight change
don’t remember the whole table, remember that 10% loss over 6 mont—significant weigth loss, more than 10%—> sever loss肙
Why is % weight change clinically relevant
predicts nutritional risk and health complications
What can weight loss predict
- Mortality - Surgical outcomes / post-operative complications - Risk of functional impairment:
Risk of functional impairment and values of weight loss
- <10% pre-illness weight; NO functional abnormalities - 10-20% pre-illness weight; loss of SOME function - >20% pre-illness weight; loss of MULTIPLE functions & PEM
What are the types of Body circumferences and areas
- • Mid-upper arm circumference (MAC)- provides an indication of skeletal muscle mass; sensitive to changes; used for screeining and monitoring
- • Mid-upper arm muscle circumference (MAMC)- an estimation of the circumference of the bone and muscle portions of the upper arm’ adjusts for subcutaneous protein and reflects some skeltal protein and bone
- • Mid-upper arm muscle area (MAMA)- estimation of the area of the bone and muscle portions of the upper arm; more responsive to change in somatic protein than MAMC
- Corrected MAMA (cMAMA)- an estimation of the area of the muscle portions of the upper arm without the bone.
- Mid-upper arm fat area (MAFA)- an estimation of the area of the far portions of the upper arm, and is simply the difference between mid-upper arm area and mid-upper arm muscle area
- • Waist circumference
What does arm measurement measure?
subcutaneous fat
What does waist circumference measure?
visceral AND subcutaneous fat (cannot be distinguished)
What does skinfold thickness indicative of?
Indicative of subcutaneous adipose tissue
What are the sites of skinfold thickness measurements?
To estimate the total amount of body fat, four skinfolds are measured:
– Triceps - most commonly used but not fully representative
– Subscapular: under the lowest point of the shoulder blade
– Biceps: front side middle upper arm –
Suprailiac: above the upper bone of the hip)
Which skinfold measurement is the most reliable?
Of all skinfold measurements, the triceps skinfold is the most reliable one to assess, because oedema is not often seen in the upper arm.
Why are skinfold measurements problematic in elderly?
he measurements are less reliable in elderly people, due to their weak skin and muscles. As a result, their muscles are often taken in the skinfold
Describe MAC
Mid-upper arm circumference (MAC) - Reflects muscle, bone, subcutaneous fat - Not sensitive to changes in muscle
Describe MAMC
- Corrects for subcutaneous fat, so it is “subtracted” from the measurement - doesn’t correct for the bone
- Insensitive to small changes in muscle
- Must measure MAC and TSF
describe MAMA
Mid-upper arm muscle area (MAMA)
- Reflects muscle and bone
- More sensitive to changes in muscle than MAMC
- More adequately reflects total body muscle mass
describe cMAMA
Corrected mid-upper arm muscle area (cMAMA)
- Reflects only muscle without the bone
- Not valid in elderly or obese
- Insensitive to small changes in muscle
describe MAFA
Mid-upper arm fat area (MAFA) - Reflects subcutaneous adipose tissue stores
- Better indicator of total body fat than a single skinfold measurement
Describe waist circumference measure and indicators
Reflective of visceral fat stores and abdominal obesity
- Measure circumference at level of iliac crest/navel
- >102 cm in men; >88 cm women
what is the connection between waist circumference, BMI and T2DM?
WC Indicates increased risk for CVD and type 2 DM independent of BMI • High BMI Low WC - Low risk • High BMI High WC - High risk
Describe Waist : Hip ratio
Estimates distribution of subcutaneous and intra-abdominal adipose and muscle tissue •
>1.0 for males; >0.8 for females
not used anymore as waist circumference is sufficient
How is waist circumference measure done?
measurement is done above ileac bone at the level of navel however, in obese individual navel is not at the level of ileac bone
What are the old and the new gold standards techniques of the body composition measures?
- Hydrodensitometry (underwater weighing) – Used to be the gold-standard
- Magnetic resonance imaging(MRI) – Is the current gold-standard
what is bod pod?
body composition measure technique Air displacement plethysmography
What is DXA?
Dual energy X-ray absorptiometry
Describe BIA
Bioelectrical impedance • Measures impedance to a low- frequency electrical current (mainly from fat) • Estimates fat mass, fat-free mass, total body water
Advantages and limitations of BIA
advantages: Rapid, safe, non-invasive • Different instruments limitations: – Influenced by hydration status – Less precise in a typical bodies – Reference data is limited - the equation installed in the scanner is unknown and cannot be adjusted for different weights and body shapes
What can BIA can be used for apart from body composition measures?
body water content
Describe DXA
• Imaging technique, based on attenuation of radiation from different tissue densities – Measures bone, soft lean and fat tissues, whole body and segments – Sufficient precision to assess short (≊8-12 weeks) and longer-term changes • Recognized as a reference method measures atteniuation of X-ray by the tissues the more dense-> the more attenuation
What are the limitations of DXA?
– Expensive but increasingly accessible in research settings – Assumes normal hydration status - in obese individuals there’s more variability and less and some of them don’t fit
What are the advantages of DXA?
– Minimal exposure to radiation
Describe bod pod
Air displacement (BOD POD) • Total body volume measured by air displacement in a chamber • Comparable to hydrostatic weighing: – Based on fat and lean tissue density
Limitations of Bod Pod
– Access to instruments – Residual lung volume must be measured
1 oz= _ g
1 oz= 30 g
1lb = __g
1lb = 454g
1 in = __ cm
1 in = 2.54 cm
1 feet = __ m
1 feet = 0.308 m
