Biochemical Assessment of Nutritional Status

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1

Biochemical Tests

-provide most objective and quantitative data on nutritional status

-can often detect nutrient deficiencies before anthropometric meaurements and clinical symptoms

2

2 general categories of biochemical test

Static
Functional

3

Static Tests

-direct tests
-measurement of nutrient of metabolite in (BLOOD,URINE,BODY TISSUE)
-may not reflect overall nutrient status vs. levels in specific tissue tested

4

Functional Tests

-indirect tests
-measures physiological processes for optimum performance
-tend to be non-specific may indicate general nutritional status but not specific nutrient deficiency

5

Biochemical can be used to

-examine validity of other methods of measuring dietary intake

-to determine if respondents are accurately reporting intake

6

Non-nutritional factors may influence test results

examples

7

Biochemical test must be used in conjunction with

anthropometric, clinical, and dietary methods

8

Roles of protein in body:

-Structural: muscles, connective, tissue, bone matrix
-regulatory: hormones, enzymes
-fluid acid base balance
-immune function

9

2 compartment model (Protein Status)

-Somatic protein

-Visceral protein

10

Somatic Protein

protein found within skeletal muscle

11

Visceral Protein

protein within organs, in RBCs & WBCs, and serum proteins

12

Protein-energy malnutrition (PEM)

-also called protein-calorie malnutrition (PCM)

13

____ more common in developing countries

protein status

14

Assessment of ______ _______ essential to the prevention, diagnosis, and treatment of PEM

protein status

15

Causes of PEM:

Primary: inadequate food intake
Secondary: other diseases leading (insufficient food intake, inadequate nutrient absorption or utilization, increased nutritional requirement, increased nutrient)

16

Test of Protein Synthesis

-Creatine
-Nitrogen Balance
-Serum Proteins
-Immunocompetence

17

Creatinine

-a product of skeletal muscle that is excreted in a relatively constant proportion to the mass of muscle in the body
-Extimates body muscle mass

18

Creatinine Excretion

-24 hour creatinine excretion
-Lean body mass extimated by comparing 24 hour creatinine excretion with
M: 23mg/kg F:18mg/kg

19

____ expressed as percent of expected value

CHI

20

CHI formula

CHI= 24hr. urine creatinine (mg)/ expected 24 hr creatinine x100

21

Creatinine-Heaight Index (CHI)

Ratio of pt's measured 24 hour creatinine excretion and the expected exretion of a reference adult of same ht. and gender

22

60-80% CHI

Mild protein depletion

23

40-60% CHI

Moderate protein depletion

24

< 40% CHI

Severe protein depeletion

25

_____ is a state in which the amount of nitrogen in (consumed as protein) equals the amount of nitrogen excreted by body

Nitrogen Balance

26

______ is expected state in healthy adults

Nitrogen balance

27

Occurs when nitrogen intake exceeds nitrogen loss

Positive Nitrogen Balance

28

Positive Nitrogen Balance ex..

-anaboloic state
-growth during childhood and adolescence
-recovery from trauma, surgery, or illness

29

Negative Nitrogen Balance

when losses exceed nitrogen intake

30

Negative Nitrogen Balance ex.

-catabolic state
-insufficient protein intake
-infection, trauma, surgery, illness
-periods of excessive protein loss (burns, GI or renal disease)

31

1g Nitrogen =

6.25 g protein

32

Nitrogen balance equations =

(protein intake/6.25)- UNN - 4

33

Useful in
-assessing protein status
-pt. is at risk of medical complication
-pt. response to nutritional support

Serum Proteins

34

Measuring serum proteins is usually _____ and _____

simple and accurate

35

Use of serum proteins based on

assumption that decreases concentrations are due to decreased liver production (primary site of synthesis)

36

Limited supply of amino acids or decrease in liver's ability to synthesize _____

Serum Proteins

37

Cannot always determine extent to which nutritional status or liver functions affects _____

serum protein concentrations

38

Factos other than inadequate protein intake affect _____

serum protein concentrations

39

Most abundant serum protein & synthesized in liver

Albumin

40

Maintains fluid/electrolyte balance & transport of substances

Albumin

41

indicates depleted protein status and decreased dietary intake

Albumin

42

Low concentrations associated with increased morbidity/mortality in hospital pt's.

Albumin

43

Limitations for albumin:

-long halflife (18-20 days)
-large body pool causes serum levels to repsond slowly to food change
-POOR INDICATE EARLY PROTEIN DEPLETION/REPLETION

44

DECREASED albumin

liver disease, kidney disease, infection, surgery, cancer, burns

45

Fluid status affects Albumin levels

decreases when blood volume increases (heart failure, renal failure)

increases with dehydration

46

Synthesized in liver & bind/transports iron in plasma

Transferrin

47

Better indicator than albumin bc smaller body pool/shorter half-life (8-9 days)

Transferrin

48

Transferrin levels decreased by

liver disease, kidney disease, infections, surgery, trauma, burns

49

Transferrin levels increased by

pregnancy, blood loss

50

______ levels inversely related to iron stores (levels are high in iron deficiency/ low when too much iron)

transferrin

51

Also called transthyretin or thyroxine-binding ________

Prealbumin

52

-Synthesized in liver
-trasport protein for thyroxine/carrier for retinol-binding protein
-more sensitive indicator of protein status due to short half/life (2-3 days)
-small body pool

Prealbumin

53

Factors that affect levels of Prealbumin

-decreased in liver disease
-infection, state, trauma
-increased in chronic renal failure pt's on dialysis

54

A liver protein that acts as a carrier for retinol (Vit A). Responds quickly to depletion/repletion of protein and energy

Retinol-Binding Protein

55

Responds to adequate energy in absence of sufficient protein. Half-life (12hrs) much shorter than prealbumin and body pool very small (complicates measurement)

Retinol-Binding Protein

56

Levels increased in renal disease
Levels decreased in Vit. A deficiency, surgery, trauma

Retinol-Binding Protein

57

What is the normal (reference) values for Albumin?

3.5-5.0g/dl

58

What is the normal (reference) values for Transferrin?

200-400mg/dl

59

What is the normal (reference) values for Prealbumin?

19-43 mg/dl

60

What is the normal (reference) values for Retinol-Binding protein?

2.1-6.4 mg/dl

61

Degree of malnutrition for Albumin? (mild, moderate, severe)

Mild: 2.8-3.4
Moderate: 2.1-2.7
Severe: < 2.1

62

Degree of malnutrition for Prealbumin? (mild, moderate, severe)

Mild: 10-18
Moderate: 5-9
Severe: <5

63

Close and complex relationship exists between nutrition and ______

immunity

64

Nutritional deficiencies can lead to impaired ________, infection, and ________.

-immunocompetence
-inflammation

65

Immune responses sensitive to impaired nutritional status but often lack ______

specificity

66

Varity of factors other than nutritional status can also affect _______

immunocompetence

67

Immune system's defense mechanisms can be divided into 2 broad categories?

-non-specific
-specific

68

Non-specific:

1st line of defense against infectious agents and are not influenced by prior contact with infectious agents (skin, mucous membranes, phagocytes)

69

Specific:

act in response to exposure to specific infectious agents and antigens- involves T-lymphocytes and B-lymphocytes (specific immunity more affected by malnutrion

70

Total number of lymphocytes reduced as protein ______ occurs

depletion

71

Complete blood counts routinely measured in hospitals.... Is total lymphocyte count easily determind?

yes.

72

Factors affecting TLC besides nutritional status inculde?

-Cancer, inflammation, infection, stress, and certain drugs

73

TLC Interpretation (mild, moderate, severe)

Mild: 1200-1800
Moderate: 800-1199
Severe: <800

74

_______ is most common single nutrient deficiency in US

Iron deficiency

75

Groups at risk for deficiency include:

-infants and young children
-adolescent
-females during child-bearing
-pregnant women

76

_______ results when consumption or absorption of dietary iron is inadequate to meet iron losses or requirement

Iron deficiency

77

Heme vs. Non-Heme

Heme: contains nonprotein portion of the HBG: Animal sources (liver, seafood, lean meat, poultry) absorbed well

Non Heme: Plant sources (dried beans/veggies) milk has no iron. corn poor

78

Nutrients that promote iron absorption:

Vit C, MFP factor (Meat, fish, poultry)

79

Nutrients that inhibit iron absorption:

phytates, fiber, calcium, phosphorus, tannins in tea and coffee

80

A deficiency in the :
-size of RBCs
-# of RBCs
-the amount of hemoglobin

Anemia

81

Anemia may result from:

-iron
-folate
-vit B12

82

Other causes of Iron deficiency:

-blood loss
-infection
-hereditary blood disorders
-chronic liver/kidney disease

83

Types of anemia that are characterized as RBCs:

microcytic, macrocytic, hypochromic

84

Microcytic

RBCs smaller than normal

85

Macrocytic

RBCs larger than normal

86

Hypochormic

RBCs paler than normal

87

Iron-deficiency anemia leads to decrease in _________ production.

HGB

88

Stages of Iron Depletion

1: depleted iron stores (no physiologic effects, represents vulnerability)
2: iron deficiency without anemia (mild physiologic effects)
3. iron-deficiency anemia

89

Effects or iron deficiency:

-decreased work -apathy
-fatigue -pale skin
-weakness -poor temp reg
-headaches

90

What test at what stage of iron deficiency?

1: serum ferritin level
2. transferrin saturation/erythrocyte protoporphyrin
3. hemoglobin/mean corpuscular volume

91

Proteins needed in Iron Absorption?

-transferrin (transfers iron)
-ferritin (primary storage form of iron)
-hemosiderin (iron storage form made in times of iron overload)

92

Mucosal transferrin to

blood transferrin

93

If cells do not need iron where does it go?

It is excreted in the feces

94

Biochemical Tests

-serum ferriitin -transferrin saturation -erythrocyte protoporpyrin
-hemoglobin -hematocrit -mean corpuscular volume

95

____ is primary storage form for iron in body

Ferritin

96

___ of all iron in body is in the storage form, most as ______

30% , ferritin

97

______ occurs before changes are seen in RBCs, other indicators, or before anemia occurs

Decrease

98

Once serum stores depleted, _______ levels no longer reflect severity of iron deficiency.

serum ferritin

99

Serum Ferritin levels _____ indicative of iron deficiency

< 12 ug/L

100

Iron transported in the blood bound to ___

transferrin

101

Only ___ of avaible iron-binding sites are occupied

30%

102

___________ measures amount of iron capable of being bound to serum proteins and provides indirect estimate of serum transferrin

Total iron-binding capacity (TIBC)

103

________ is ratio of serum iron to TIBC and is calculated like (TS=Serum Iron/TIBC x 100

Transferrin saturation

104

____ is percent of transferrin that is saturated with iron

Transferrin saturation

105

Serum iron levels decrease and TIBC increases, resulting in a decreased TS

Iron-deficiency

106

TS of _____ is in indicative of iron deficiency

<16%

107

directly proportional to the body's requirement for iron (erythrocyte-producing cells of bone marrow)

Serum Concentration of sTfR

108

begins to increase in early iron deficiency before anemia develops (2nd stage of depletion)

Serum sTfR

109

valuble for iron deficiency diagnosis/monitoring erythropoiesis, especially before anemia develops

Serum sTfR concentrations

110

Not affected by inflammation or infection

Serum sTfR

111

_____ began measuring sTfR in 2003

NHANES

112

key model used by NHANES to assess iron status in children 1 to 5/ women of childbearing age.

Serum sTfR concentration

113

_____ is precursor of heme

protoporphyrin

114

_______ accumulates in RBCs when amount of heme that can be produced is limited by iron deficiency

protoporphyrin

115

__________ > 1.24 umol/l RBC indicative of iron deficiency

erythrocyte protoporphyrin

116

_______ is iron-containing molecule found in RBCs that carries oxygen

hemoglobin

117

grams of hemoglobin per deciliter of blood is an ___ of the bloods oxygen-carrying capacity

Index

118

measurement of hemoglobin in whole blood is ______ __ _____ _____ ___ for iron-deficiency anemia

most widely used screening test

119

amount of hemoglobin in blood depends on number of _____ and ______ of hemoglobin in each RBC

RBC , amount

120

Hemoglobin (normal) values:

M 14-18g/dl (<14 iron-deficient) W 12-16 g/dl (< 12 iron-deficient)

121

Hemoglobin considerations:

african americans, pregnancy, gender

122

Hematocrit (Hct) also known as

packed cell volume

123

Percentage of RBCs making up the entire volume of whole blood

Hematocrit (Hct)

124

depends larely on the number of RBCs and to a lesser extent on their average size:

hematocrit

125

Hematocrit (normal) reference range:

M: 40-54% W: 37-47%
(<40 iron-deficient) (<37% iron-deficient)

126

What is MCV?

Mean Corpuscular Volume

127

____ is a measure of the size (volume) of the average RBC

MCV

128

How is MCV calculated?

dividing the hematocrit by the RBC count

129

Normal values for MCV

80-100
-Iron-deficiency anemia (<80fl)

130

RBCs smaller than average

microcytic

131

In folate or vit B12 deficiency, RBCs are larger than averager

macrocytic: >100fl

132

Amount of Hbg in RBCs

influenced by the size of RBCs

133

How to determine if cells are hypochromic? values

Values : 26-34 pg/dl

134

Include a variety of test performed on plasme or serum that are useful in diagnosis and management of disease

blood chemistry test

135

What do blood chemistry tests test?

electrolytes, enzymes, metabolities,

136

When several tests are run at once

chemistry profile, chemistry panel, chem profile

137

Example of blood chemistry test (cororany risk profile)

includes triglyceride, total cholesterol, HDL-C, LDL-C

138

Increased BUN (blood urea nitrogen) usually indicates

Renal failure

139

BUN (blood urea nitrogen) is usually _______ with dehydration, gastrointestinal bleeding, congestive heart failure, high protein intake, insufficient renal blood supply, blocked urinary tract

elevated

140

_____ BUN (blood urea nitrogen) results from liver disease, overhydration, malnutrition, or anabolic steriod use

decreased

141

Serum levels of LDH rise 12-24 hours following a _________

myocardial infection (MI)

142

Lactate Dehydrogenase is often measure to determine if a ___ has occured

MI

143

LDH (lactate dehydrogenase) is _______ with hepatitis, cancer, kidney disease, burns, trauma

increased

144

____ leading cause of death of American males/females. 13 million Americans alive today have CHD

CHD (coronary heart disease)

145

Coronary heart disease is also referred to as

-Coronary artery disease (CAD)
-Cardiovascular disease (CVD)

146

Evidence suggests that CHD begins in ________ - progresses slowly into adulthood

childhood

147

Leading causes of death

1. heart disease
2. cancer
3. stroke
4.diabetes

148

4 Modifiable risks!

1. smoking
2. hypertension
3. High blood cholesterol
4. sedentary lifestyle

149

Strong causual relationship between elevated _____ and _____

LDL-C and CHD

150

Risk of CHD increases proportionally with ______

LDL-C

151

____ rare in those with low LDL-C, even in the presence of other factors

CHD

152

____ is prime target in attempts to lower blood cholesterol levels

LDL

153

High ____ levels protective against CHD

HDL

154

high _____ levels, risk of CHD is relatively low,

HDL-C

155

___ HDL-C levels increased CHD risk.

low

156

Most clinical labs do not measure ____ directly

LDL-C

157

Calculations are usually based on ______, _______, _____.

total cholesterol, HDL-C, triglyceride

158

Formula for calculating LDL-C

LDL-C=TC-HDLC - (TG/5)

159

CHD risk ___ with total cholesterol.

Increases

160

Increase risk is greatest when level rise above

200mg/dl

161

For every __% decrease in TC, CHD risk decreases ____%

1, 2

162

Classification of TC
Desirable?
Borderline High?
High?

1. < 200
2. 200-239
3. > 240

163

Classification of LDL Cholesterol
Optimal?
Near or above optimal?
Borderline High?
High?

1. < 100
2. 100-129
3. 130-159
4. > 160

164

Classification of HDL Cholesterol
Low HDL?
Protective HDL?

1. < 40
2. > 60

165

Lipoprotein ratios indicate _______ risk

vascular

166

predictive value of CHD greater than TC, LCL, HDL alone

Lipoprotein ratios

167

Ratio TC/HDL primary prevention targets

men <4.5, women <4.0

168

At risk ratio for TC/HDL

men >5.0, women >3.0

169

As ___ increases with HDL-C, risk increases to

TC

170

At risk level LDL/HDL

men > 3.5, women >3.0

171

The ____ ratio is as useful as the TC/HDL ratio

LDL/HDL

172

___ is similar to TC/HDL because 2/3 of plasma cholesterol are found in LDL.

LDL/HDL

173

Studies of relationship between TG (triglyceride) levels and CHD risk have _____ results

conflicting

174

NCEP recognizes elevated ___ as independent risk factor for CHD

TG

175

Classification for TG
normal
borderline high
high
very high

Normal: <150
Borderline high: 150-199
High: 200-499
Very High: >500

176

CHD RISK assessment. Complete lipid profile?

TC, LDL-C, HDL-C, TG

177

all adults ____ should have a fasting lipoprotein profile performed at least once every 5 yrs.

>20 years

178

_______ is required for the accurate measurement of trigylcerides, which is required for calculation of LDL-C

fasting

179

_______ and ________ can be accurately measured in non-fasting state

Total Cholesterol, HDL-C

180

____ one of most common risk factors for CHD and Renal disease

High Blood Pressure

181

Blood pressure expressed in millimeters of _____ (mm Hg)

mercury

182

________ = "top number"

systolic blood pressure
-BP following cardiac contraction

183

___________= "bottom number"

Diastolic blood pressure
-BP following cardiac relaxation

184

BP Classifications
normal
prehypertension
stage 1 hypertension
stage 2 hypertension

Systolic BP / Diastolic BP
<120 / <80
120-139/ 80-89
140-159/ 90-99
>160 / >100

185

Hypertension (HTN) if often _______.

undiagnosed

186

____% of persons with HTN are aware of condition

<70%

187

_____ of people with HTN are treated

half

188

________ have adequate control of BP

< 30%

189

What are some risk factors for HTN?

alcohol, stress, tabacoo, diabetes, obesity

190

group of metabolic diseases characterized by hyperglycemia resulting from defects in insulin secretion, insulin action, or both

Diabetes Mellitus (DM)

191

_________ __________ associated with DM is associated with long-term damage, dysfunction, and failure of various organs, especially the eyes, kidneys, nerves, heart and blood vessels

Chronic Hyperglycemia

192

Symptoms of DM

Extreme thirst, frequent urination, dry skin, hunger, blurred vision, drowsiness, nausea

193

-abnormal carb/lipid metabolism
-retinopaty w/ potential loss of vision
-nephropathy leading to renal failure
-peripheral neuropathy with risk of foot ulcers and amputation

Complications of DM

194

3 Types of Diabetes

Type 1, Type 2, Gestational

195

Type 1 diabetes

-insulin dependent
-juvenile onset

196

Type 2 diabetes

-non insulin dependent
-adult onset

197

Gestational

-pregnant women

198

10-20% of all cases of diabetes

Type 1 DM

199

Insulin producing cells in pancreas destroyed >>>>>> no insuiln

type 1 DM

200

possible viral or auto-immune cause

type 1 DM

201

How is type 1 diabetes treated?

-insulin shots
-balance, timing, and amounts of food/insulin/exercise

202

80-90% of DM cases

type 2

203

Produces insulin, but not effective
-body resists/ignores it

Type 2 DM

204

Rate increases with age/ correlated with obesisty

Type 2 DM

205

How is Type 2 DM treated?

-oral medication
-weight loss may correct insulin resistance
-balance, timing, and amounts of: medication, food,exercise

206

Defined as any degree of glucose intolerance with one=set or first recognition during pregnancy

Gestational DM (GDM)

207

____ weeks post pregnancy, woman should be reclassified

>6

208

in majority of cases of GDM, glucose regulation will return to normal after _______

delivery

209

GDM complicates _____ of pregnancies

7%

210

risk assessment for GDM should occur at first ________ visit

prenatal

211

High risk characteristics for GDM:

-obesity
-personal history of GDM
-glucose in urine
-strong family history

212

if not found to GDM at initial testing, should be retested at _____ weeks gestation

24-28

213

Women of average risk should have testing at ___ weeks gestaton

24-28

214

Involves having patient drink a beverage containing a known amount of glucose (usually 75 grams for adults)

Oral Glucose Tolerance (OGTT)

215

Blood drawn immediately before the glucose load and then at set intervals. Plasma glucose measured at 1 hr intervals for 2 or 3 hrs.

Oral Glucose Tolerance Test (OGTT)

216

Diagnosis criteria for OGTT

2 hr plasma glucose >200 mg/dl during an oral glucose tolerance test

217

Diagnosis Criteria for DM

symptoms plus glucose concentration >200mg/dl "casual"=no meal timing
fasting plasma glucose >126 mg/dl "fasting"=no meal w/in 8 hrs.

218

Diagnosis for pre-Dm
1. Impaired glucose tolerance (IGT)
2. Impaired fasting glucose (IFG)
both refer to metabolic stage between normal glucose homeo/diabetes

IGT=2hr plasma glucose >140mg/dl, <200 mg/dl in an OGTT
IFG= fasting plasma glucose leves >110mg/dl, but <126 mg/dl
-109mg/dl=upper limit of normal

219

As many as ____ of people with DM are undiagnosed

50%

220

_______ recommended screening method

Fasting plasma glucose (vs. OGTT)

221

Criteria for testing DM

-45 yrs
-BMI >25

222

Testing should be done early is the pt. has a number of risk factors such as

->25
-relative with DM
-physically inactive
-member of high risk pop (black, hispanic, native american, asain)

223

Additional Risk factors for DM

-had a baby with over 9lbs/diagnosised with GDM
-hypertensive
-HDL-C <35, TG >250
-history of vascular disease

224

Best screening for DM is the _________

fasting plasma glucose test (FPG)

225

FPG and OGTT are both suitable, but FPG is preferred in a _____ setting.

clinic
-easier/faster
-more convenient/acceptable for pt.
-less expensive

226

_____ glycemic status is cornerstone for diabetes care

monitoring

227

Results of monitoring used to assess efficacy of therapy and to guide adjustments in _________ ________ _______

medical therapy (MNT), exercise, and medications to achieve the best possible blood glucose control

228

Blood glucose monitoring by patients

-self-monitoring
-critical to mainting glycemic control
-typically dont by strips
-allows people to keep track

229

Recommendations for monitering type 1

-SMGB 3x per day
-before meal and bedtime

230

Recommendations for Type 2

-diet/exercise controlled -1/2x per week
-oral hypoglycemic agents
-insuin 2x per day

231

Data suggest that only a moniority of pts perform

SMBG

232

Barriers to increasing use of SMBG

-cost
-inadequate understanding
-psychological/physical discomfort
-inconvenience

233

Measurement of glycated proteins, primarily __________ , provide info on average glycemia over weeks and months

hemoglobin

234

Also referred to as glycated hemoglobin, glybohemoglobin, HbA or the AIC test

Glycosylated Hemoglobin Testing

235

________ (RBCs) freely permeable to glucose

erythrocytes

236

______ in blood sample provides glycemic history of previous 120 days.
-reflects previous 2-3 months of glycemic control

Level of HbA1c

237

_____ is preferred standard for assessing glycemic control

HbA1c

238

Risk factors for Metabolic syndrom

-central obesity
-high blood pressure
-high TG
-Low HDL-C
-insulin resistance
-