Introduction to Clinical Nutrition
NFSC 370
D. Bellis McCafferty
Illness
Example : Cancer
Altered
Food Intake
Examples: Loss
of appetite,
altered food
likes/dislikes,
difficulty chewing
and swallowing,
reduced saliva
secretion
Altered
Digestion and
Absorption
Examples:
radiation enteritis,
surgical resection
of GI tract,
diarrhea
Altered
Metabolism
Example:
increased energy
needs due to
altered energy use
in cancer
Malnutrition
Altered
Nutrient
Excretion
Examples: fecal
loss of fat-soluble
vitamins and
calcium in clients
with cancers that
affect enzyme
secretion or bile
salt production
Clinical Nutrition
(Medical Nutrition Therapy)
Purpose
– To achieve or maintain good nutritional status.
American Dietetic Association
– Professional organization representing
Registered Dietitians (RD) and Dietetic
Technicians (DTR)
Patient Care: Team Approach
(Interdisciplinary)
• Physician
• Registered Dietitian
• Registered Nurse, Licensed Vocational
Nurse, Certified Nursing Assistant
• Pharmacist
• Speech Therapist
• Occupational Therapist
• Social Worker
The Nutrition Care Process
• Identifying and meeting a person’s nutrient and nutrition
education needs. Five steps:
1. Assess Assessment of nutritional status
2. Analyze Analyze assessment data to determine nutrient
requirements
3. Develop Develop a nutrition care plan to meet patient’s
nutrient and education needs.
4. Implement: Implement care plan
5. Evaluate: Evaluate effectiveness of care plan: ongoing
follow-up, reassessment, and modification of care plan.
THE PATIENT
SHOULD BE AN ACTIVE
PARTICIPANT IN THE
CARE PROCESS!
Assessing Nutritional Status
• Historical Information
• Physical Examination
• Anthropometric Data
• Laboratory Analyses
Historical Information
• Health History (medical history) - current
and past health status
– diseases/ risk factors for disease
– appetite/food intake
– conditions affecting digestion, absorption,
utilization, & excretion of nutrients
– emotional and mental health
Historical Information
• Drug History
– prescription & OTC meds
– illicit drugs
– nutrient supplements, HERBS and other
“alternative” or homeopathic substances
– multiple meds (who’s at risk?)
Meds can alter intake, absorption, metabolism, etc.
Foods can alter absorption, metabolism, &
excretion of meds.
Historical Information
• Socioeconomic History - factors that affect one’s
ability to purchase, prepare, & store food, as well
as factors that affect food choices themselves.
– Food availability (know local crops/produce)
– occupation/income/education level
– ethnicity/religious affiliations
– kitchen facilities
– transportation
– personal mobility (ability to ambulate)
– number of people in the household
Historical Information
• Diet History—analyzing eating habits, food intake,
lifestyle, so that you can set individualized,
attainable goals.
–
–
–
–
–
–
–
–
Amount of food taken in
Adequacy of intake – omission of foods/food groups
Frequency of eating out
IV fluids
Appetite
Restrictive/fad diets
Variety of foods
Supplements (overlaps)
Historical Information
• Tools for taking a diet hx:
–
–
–
–
–
24 hour recall
Usual intake – can find trends, such as breakfast/snacks
Food Frequency Questionnaire/Checklist
Food Records
Observing food intake
• Analysis of Food Intake Data
• INDIVIDUAL NEEDS FOR NUTRIENTS VARIES
Assessing Nutritional Status
• Historical Information
• Physical Examination
• Anthropometric Data
• Laboratory Analyses
Physical Examination: “A picture is
worth a thousand words.”
• weight status
• mobility
• confusion
• signs of nutrient deficiencies/malnutrition
– esp. hair, skin, GI tract including mouth and tongue
• Fluid Balance (dehydration/fluid retention)
Physical Examination: “A picture is
worth a thousand words.”
• Limitations of Physical Findings
– Depends on assessor!
– Many physical signs are nonspecific: ie. cracked lips
from sun/windburn vs. from malnutrition,
dehydration…
Assessing Nutritional Status
• Historical Information
• Physical Examination
• Anthropometric Data
• Laboratory Analyses
Anthropometric Data - physical measurement
of the body
anthropos = human
metric = measure
• Indirect assessment of body composition and development
• Used in Nutrition Assessment:
– Measures using height and weight
– Measures of body composition (fat vs. lean tissue)
– Functional Measures
Anthropometric Data
Measures Using Height and Weight
BMI Body Mass Index
wt (kg)
ht (cm)2
or
wt (lb) X 705
ht (inches) 2
Anthropometric Data
Measures Using Height and Weight
•
•
•
•
18.5-24.9
25+
30+
Pros:
– many studies have identified the health risks
associated with a wide range of BMIs
– easy to look up on chart
– screening tool
Anthropometric Data
Measures Using Height and Weight
• Cons: BMI can misclassify up to one out of
four people.
– Does not account for fat distribution
– Doesn’t account for LBM - may misclassify
frail/sedentary or very muscular people
Met Life Insurance weight-for- height tables
– Weights based on lowest mortality
Example: Height & Weight Table For Women
Feet Inches
SmallFrame
MediumFrame
LargeFrame
5' 1"
106-118
115-129
125-140
5' 2"
108-121
118-132
128-143
5' 3"
111-124
121-135
131-147
5' 4"
114-127
124-138
134-151
5' 5"
117-130
127-141
137-155
5' 6"
120-133
130-144
140-159
5' 7"
123-136
133-147
143-163
5' 8"
126-139
136-150
146-167
5' 9"
129-142
139-153
155-176
Weights at ages 25-59 based on lowest mortality. Weight in pounds
according to frame (in indoor clothing weighing 3 lbs.; shoes with 1"
heels)
Anthropometric Data
Measures Using Height and Weight
Assessing “Ideal Body Weight”
Hamwi Equation:
• Females: 100# for first 5’ of height, plus 5# per
inch over five feet
• Males: 106# for first 5’ of height, plus 6# per
inch over five feet
• +/- 10% to calculate a range
(for those under 5’ tall, subtract 2 lb. per inch under
5’)
** Amputations, immobility:
7%
Whole
arm
6.5%
43%
Below elbow 3%
Hand 1%
Above knee 13%
Below knee 6%
Foot 1.8%
Whole
leg
18.5%
Interpretation
%IBW
Actual (present) weight X 100 = %IBW
IBW
• example: 5’6” woman weighs 160#. What is
her % IBW?
• 160  130 = 123%
Interpreting % IBW
 200% IBW = morbidly obese (or 100# over IBW)
 120 % (130%) = obese
110 - 120 = overweight
90 - 109 = normal
80 - 89 = mildly compromised nutrition status (mild
malnutrition)
70-79 = moderate
< 70% = severe
Anthropometric Data
Measures Using Height and Weight
• Assessing “Usual Body Weight”
Actual (present) weight X 100 = % UBW
UBW
• example: 110# female lost 10# over past month
• 110/120 x 100 = 91.6% UBW, or loss of about 8%
Interpreting % UBW
85-90% mild
75-84% moderate
<75% severe
OR wt. change (unintentional weight loss)
mild
moderate
severe
1 week
1-2%
>2
1 month
5
>5
3 months
7.5
>7.5
6 months 10
10-15
>15
Anthropometric Data
Measures of Body Composition
(fat vs. lean tissue)
Body Fat Measurements
• fatfold (skinfold)
• waist-to-hip ratios
• hydrodensitometry (hydrostatic weighing)
• bioelectrical impedance
Anthropometric Data
Measures of Body Composition
Midarm muscle circumference – indirectly
measures protein status by estimating arm
muscle mass.
• Midarm circumference and triceps fatfold
• plug into an equation:
mmc (cm) = mc (cm) - [.314 x triceps fatfold (mm)]
Anthropometric Data
Functional Measures of Nutrition Status
Hand Grip Strength
• Dynamometer
• Not appropriate w/arthritis/muscular
disorders
Interpreting Measurements
• Requires caution
• Interpreting Measurements
– Sometimes difficult to measure 2’ mobility
problems, injury, loose, hanging skin
– Hydration/dehydration affects weight, fatfolds,
and MAMC
– Standards used are controversial
Summing Up
• Anthropometric measures provide valuable
information regarding body wt. and
composition
• Do not reflect nutrition status alone
• Accuracy requires on the skill of the
assessor
• Caution interpreting results
Assessing Nutritional Status
• Historical Information
• Physical Examination
• Anthropometric Data
• Laboratory Analyses
Laboratory Analyses
• Help determine what’s happening on the inside
of the body
• Automated measurements of several blood
components from a single blood sample
• serum -
• plasma -
Laboratory Analyses
Interpreting Biochemical Tests
• Many can be skewed with fluid retention or
dehydration.
• Over-hydration can cause _____ numbers
• Dehydration can cause ______ numbers
• These are clues that anthropometrics are
probably skewed as well.
Normal
hydration
Overhydrated =
diluted blood
Dehydrated =
concentrated blood
1 dl blood
10 mg/dl
5 mg/dl
20 mg/dl
Laboratory Analyses:
Biochemical Tests Of Protein Status
• Somatic proteins - physical work
• Serum/visceral proteins (circulating proteins &
proteins found in the liver, kidneys, pancreas,
and heart)
maintain fluid balance
synthesize enzymes and hormones
mount immune response
heal wounds
• Therefore, protein status is an indicator of
immune response.
Laboratory Analyses:
Biochemical Tests Of Protein Status
• Synthesized in the liver
– May reflect liver function
– Measurements skewed if liver diseased
• Remember, when kcals are inadequate, protein is
used to make glucose.
Laboratory Analyses:
Biochemical Tests Of Protein Status
Serum Albumin:
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–
–
–
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>50% total serum protein
Helps maintain fluid and lyte balance
Transports many nutrients, hormones, drugs, etc.
Used as indicator of protein status (visc. protein stores)
Half life ___________
3.5-5.0 = adequate
2.8-3.4 = mildly depleted
2.1- 2.7 = moderately depleted
<2.1 = severely depleted visceral protein stores
Laboratory Analyses:
Biochemical Tests Of Protein Status
Problems with albumin:
– not very sensitive, long half life
–  levels reflect prolonged depletion, but
– normal levels may not reflect short term changes in
nutritional status.
• Levels  :
• Remember, number affected by plasma volume,
so  in over-hydration and  in dehydration.
Laboratory Analyses:
Biochemical Tests Of Protein Status
Serum Transferrin
= (TIBC x 0.76) + 18
– Shorter half-life ____________
– Transports iron:
– If Fe deficiency present, doesn’t accurately reflect
protein status
– Transferrin levels RISE with Fe deficiency! Inverse
relationship
–  levels may indicate __________________
–  levels may indicate __________________
Laboratory Analyses:
Biochemical Tests Of Protein Status
– Levels  :
– Levels  :
Normal:
Mild
Moderate
Severe
>200 mg/dl
150-200 mg/dl
100-149 mg/dl
<100 mg/dl
Laboratory Analyses:
Biochemical Tests Of Protein Status
Prealbumin (thyroxine-binding prealbuin or
transthyretin TTHY)
– Being used more: some facilities using in place of
albumin
– Half life: ______________
– Sensitive indicator of protein status
– Good indicator of pt. response to MNT
–  $$ to run than albumin
Laboratory Analyses:
Biochemical Tests Of Protein Status
Prealbumin
– Levels  :
– Levels  :
Normal:
Mild:
Moderate:
Severe:
15-40 mg/dl
10-15 mg/dl
5-10 mg/dl
<5 mg/dl
Laboratory Analyses:
Biochemical Tests Of Protein Status
Nitrogen Balance Studies
(usually only used in severe metabolic stress)
1. Track the patient’s UUN (Urinary Urea Nitrogen)
2. 24 hour record of protein intake
3. Plug into nitrogen balance equation:
N balance (g) = protein intake - (UUN + 4)
6.25
Remember how this works?
Amino Acids
C-C-N
C-C-N
Urea
(BUN)
N-C-N
Excreted via kidneys
(UUN)
N balance (g) = protein intake - (UUN + 4)
6.25
• “4” represents non-urea N+ lost in feces, urine,
skin, and respiration
• every 6.25 grams of protein contains 1 gram of
nitrogen
0 or - =
+ =
• Goal for repletion :
Laboratory Analyses:
Biochemical Tests Of Immune Function
•
•
•
•
Total WBCs
Normal: 5,000-10,000/mm3
Possible critical values: <2500 or >30,000/mm3
High vs. low values?
• Total Lymphocyte Count (TLC)
Measured from % lymphocytes and total WBC count
Equation: TLC = % lymphocytes X Total WBC/mm3
Normal: >1500 mm3
Mild: 1200 - 1500
Moderate: 800-1199
Severe: <800
What do unusually high numbers indicate?
Laboratory Analyses:
Hematological Assessment – looking at blood cells and
detecting anemias
Hematology Assessment – morphology &
physiology of blood cells. Helps detect the presence
of anemias.
• Hemoglobin (Hgb, Hb)
– main functional constituent of the RBC, serving as
the oxygen-carrying protein
–  level may indicate depleted iron stores BUT
•
•
•
12-16 g/dl females
14-18 g/dl males
Laboratory Analyses:
Hematological Assessment
• Hematocrit (Hct) – % of RBCs in the total blood
volume.
– Commonly used to diagnose Fe def., but also
inconclusive
–  values indicate incomplete Hgb formation, which is
manifested by ____________, ______________ RBCs
Males: 42%-52%
Females: 37%-47%
Laboratory Analyses:
Hematological Assessment
• Mean Corpuscular Volume (MCV) - the average
volume (size) of a single RBC.
–  levels:
–  levels:
normal: 80-95m3
Anemias:
• Normocytic, normochromic anemia:
– Iron def detected early (RBCs)
• Microcytic hypochromic:
– Fe-def detected late (or lead poisoning)
• Microcytic, normochromic:
– Renal disease (2’ loss of EPO)
• Macrocytic, normochromic:
– B12 or folate def (or chemo)
Laboratory Analyses:
Other Labs Used in Nutrition Assessment
• Glucose
– Indicates glucose tolerance/diabetes.
– Levels  2° _______________, pancreatitis,
pancreatic CA, & with use of steroids (solumedrol
and prednisone),caffeine, antidepressants and
several other drugs.
– Normal Fasting:
Amino Acids
C-C-N
C-C-N
Urea
(BUN)
N-C-N
Excreted via kidneys
(UUN)
• Blood Urea Nitrogen (BUN)
– Major end product of protein metabolism
– Levels  with impaired ____________
function
– Also  with:
Laboratory Analyses:
Other Labs Used in Nutrition Assessment
• Creatinine (blood)
– Breakdown product of phosphocreatine, present in
skeletal muscle
– Daily production of creatine, (and thus creatinine)
depends on muscle mass
– Creatinine is excreted in ________ on a daily
basis.
– If _________ function is impaired, Creatinine
levels will rise (decreased clearance).
Laboratory Analyses:
Other Labs Used in Nutrition Assessment
• Sodium (Na+)
– Indicator of hydration level. Look at Na+ level to
evaluate other labs.
– Overhydration – Dehydration -
• eg. albumin