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Assessment of Nutritional StatusBiochemical assessment1Biochemical assessment2Involves measurement of nutrient levels or their metabolites in body tissues or fluids

Estimation of tissue desaturation, enzyme activity or blood compositionBiochemical assessment3Tests are confined to 2 easily obtainable fluids namely blood and urine and results are generally compared to standardsResults are generally compared to standards, i.e. normal levels for age and sex Biochemical assessment4An objective method of nutritional assessmentProvides specific information on the bodys status regarding specific nutrients and may also identify borderline nutritional deficiencies or excessesCan be used to assess the nutritional status of large population groupsAdvantages5ObjectivityIndependent of the emotional and subjective factors that usually affect the investigatorFree from bias compared to other methods of nutritional statusAdvantages6Can detect early subclinical states of nutritional deficiencyCan identify nutritional deficiency before appearance of clinical signsReveals nutrient deficiency at an early stageAdvantages7Can confirm existence of abnormality, since clinical signs are non-specificPrecision and accuracyDisadvantages8Costly, usually requiring expensive equipmentsTime consumingDifficult to collect samplesLack of practical standards of sample collectionObjectives 9To detect marginal nutritional deficiency in individuals, particularly when dietary histories are questionable or unavailable; their use is especially important before overt clinical signs of diseases appear, thus permitting the initiations of appropriate remedial steps

To supplement or enhance other studies such as dietary or community assessment among specific population groups in order to pinpoint nutritional problems that these modalities may have suggested or failed to revealFactors affecting accuracy of results10Method of sample collectionMethod of transport and storage of samplesTechnique employedIdeal Biochemical Tests11SpecificSimpleInexpensiveReveal tissue depletion at an early stageRequire less sophisticated equipment and skillCommon biochemical parameters/tests12FluidParameterNutritional deficiencyBloodSerum albuminProtein deficiencyAmino acid imbalanceProtein deficiencySerum vitamin AVitamin A deficiencySerum caroteneVitamin A deficiencySerum alkaline phosphataseVitamin D deficiencySerum ascorbic acidVitamin C deficiencyHemoglobinIron and Vitamin B12 deficiencyHematocritIron deficiencyUrineHydroxyproline excretionProtein deficiencyUrinary ureaProtein deficiencyUrinary creatinineProtein deficiencyUrinary thiamineThiamine deficiencyUrinary ribiflavinRiboflavin deficiencyChoosing the biochemical assessment method13Direct measurement of the nutrientSerum proteins (albumin, globulin, fibrinogen, carrier proteins)Blood glucoseBlood lipids : free fatty acids, total cholesterol, LDL-cholesterol, triglyceridesSerum retinol, ascorbic acid, calcium, sodium, B-vitaminsChoosing the biochemical assessment method14Measurement of substances that indirectly reflect level of the nutrient in the bodyHematocrit, hemoglobinHormones (e.g. Thyroid hormones)Binding proteins (e.g. Retinol binding proteins)Urinary excretion of metabolites (iodine, B6 deficiency: increased excretion of xanthurenic acid, other tryptophan metabolites)Choosing the biochemical assessment method15Know the physiology and metabolism of the nutrient to be measuredIs it a water or fat soluble nutrient?Can it be stored by the body in significant amounts?How are levels of the nutrient in the body regulated?What are the normal roles of the nutrient in the body?What will likely happen if the nutrient becomes deficient?What is the biological sample to be used?16BloodUrineBlood17Arterial, venous, plasma, serum, blood cells erythrocytes

Measurements of nutrients/ metabolites are often controlled by homeostasis tend to reflect recent intakeBlood18Random sampleTaken at any time of the dayDepending on what is being measured, may be influenced by recent food intake, physical activity, fluid intakeWhat is the biological sample to be used?19BloodUrineUrine20First voided morning urine sampleAssumed that subjects have been asleep for the past 6-8 hours No food and fluid intake immediately before sample takenPhysical activity standardized between different subjectsUrine2124-hour sampleMore difficult to make a complete collection, especially in free-living subjectsMid-stream sample22Breastmilk, saliva, sweat, adipose tissues, feces, hair and nails, buccal mucosal cells

Preservation of biological samples23Any separation/initial processing requiredContainers for storage and transportConsiderations (cold storage, transport)

It is of utmost importance to preserve the integrity of the collected samples prior to actual analysis in the laboratoryAssay24Analysis done to determine the presence of a substance and the amount of that substance

May be done for example to determine the level of thyroid hormone in the blood of a person suspected of being hypothyroid (or hyperthyroid)Analysis of biological samples25Methods to be used in analysisSpectrophotometryImmunological methodsChromatographySpectrophotometry26Based on the principle that different substances have different characteristics with regard to light spectrumAnalysis of biological samples27Methods to be used in analysisSpectrophotometryImmunological methodsChromatographyImmunological methods28Radioimmunoassay, enzyme immunoassay methods, based on the principle that substances have specific ability to bind to certain antigens/antibodiesAnalysis of biological samples29Methods to be used in analysisSpectrophotometryImmunological methodsChromatographyChromatography30Gas chromatography, HPLC-based on the principle that substances have differences in chemical characteristics (mol wt) that allow then to be isolated from each otherAnalysis of biological samples31Equipment required for analysisAre they available?Is the procedure being done locally?Is there a laboratory person technically trained to perform the procedure? Analysis of biological samples32Coordination of sample collection, storage and transportTechniques for collection of samplesInformed consent from subjectsMethods vary in cost, reliability, degree of technical expertise requiredInterpretation of results33Low nutrient levelsDietary deficiency Poor absorption Impaired transport Abnormal utilization Combination of factorsInterpretation of results34Compare individual results with normal reference values appropriate for:Age Sex Physiological state

Biochemical measurements of selected nutrients35ProteinIronVitamin AVitamin DVitamin EVitamin CThiamineRiboflavinNiacinVitamin B6FolateVitamin B12CalciumPhosphorusMagnesiumIodineLipid and glucoseZinc

Protein status36Laboratory indices of protein status measure somatic protein status, visceral protein status, metabolic changes, muscle function and immune functionProtein status37Proteins-body stores are determined from by-products of protein catabolism and products of protein synthesisProtein status38Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusUrinary creatinine excretion39Used to assess the degree of depletion of muscle mass in marasmic patients, and degree of repletion after long terms intervention, provided that 72-hour urine collections are madeFrequently expressed as creatinine height index Guidelines for the interpretation of creatine height index40Less than acceptableAcceptable (low risk)Deficient (high risk)Low (medium risk)Creatinine height index (3 months to 17 years of age)< 0.50.5 0.9> 0.9Source : Gibson, 1991Factors affecting daily creatinine excretion41Strenuous exerciseEmotional stressDietary intakes of creatine and creatinineMenstruationAgeInfection, fever and traumaChronic renal failureProtein status42Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein status3-Methylhistidine excretion433-methylhistidine is an amino acid present almost exclusively in the actin of all skeletal muscle fibers and the myosin of white fiber

A marker of muscle protein that is not widely usedProtein status44Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum proteins45Index of visceral protein status

Easily measured but a rather insensitive index of protein statusFactors affecting serum protein concentrations46Inadequate protein intakeAltered metabolismSpecific deficiency of plasma proteinReduced protein synthesisPregnancyCapillary permeabilityDrugsStrenuous exerciseGuidelines for the interpretation of total serum protein concentrations, g/dL47SubjectsLess than acceptableAcceptable (low risk)Deficient (high risk)Low (medium risk)Infants 0-11 months-< 5.0> 5.0Children 1 to 5 years-< 5.5> 5.5Children 6 to 17 years-< 6.0> 6.0Adults< 6.06.0 to 6.4> 6.5Pregnant, 2nd and 3rd trimester< 5.55.5 to 5.9> 6.0

Source : Sauberlich et al, 1974Protein status48Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum albumin49Reflects changes occurring within the intravascular space and not the total visceral protein poolNot very sensitive to short-term changes in protein statusHas a long half-life of 14 to 20 daysInterpretative guidelines for serum albumin concentrations, g/dL50SubjectsLess than acceptableAcceptable (low risk)Deficient (high risk)Low (medium risk)Infants 0-11 months-< 2.5> 2.5Children 1 to 5 years< 2.8< 3.0> 3.0Children 6 to 17 years< 2.8< 3.5> 3.5Adults< 2.82.8 to 3.4> 3.5Pregnant 1st trimester< 3.03.0 to 3.9> 4.0Pregnant, 2nd and 3rd trimester< 3.03.0 to 3.4> 3.5Source : Gibson, 1991Protein status51Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum transferrin52Transferrin is a serum beta-globullin protein synthesized primarily in the liver and is located almost totally intravascularlyServes as the iron transport proteinIs bacteriostatic (binds with free iron and prevents the growth of gram-negative bacteria which require iron for growth)Interpretative guidelines for serum transferrin, ug/L53ParameterProtein deficitNoneMildModerateSevereTransferrin> 200150 - 200100 - 150< 100Source : Gibson, 1991Protein status54Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum retinol-binding protein55is a carrier protein for retinolSerum RBP concentrations tend to fall rapidly in response to protein and to energy deprivation and respond quickly to dietary treatmentInterpretative guidelines for retinol-binding protein56ParameterProtein deficitNoneMildModerateSevereRetinol-binding protein (mg/dL)2.6 7.6---Source : Gibson, 1991Protein status57Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum thyroxine-binding pre-albumin58TBPA serves as transport protein for thyroxine and as a carrier protein for RBPMore sensitive index of protein status and responds more rapidly to dietary treatmentInterpretative guidelines for thyroxine-binding pre-albumin59ParameterProtein deficitNoneMildModerateSevereThyroxine-binding pre-albumin (mg/dL)15.7 29.610 - 155 - 10< 5Source : Gibson, 1991Protein status60Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum somatomedin-C61Somatomedins are growth-hormone dependents serum growth factors produced by the liverCirculate blood to carrier proteins and have a half-life for several hoursMore sensitive to acute changes in protein status than the other serum proteinsProtein status62Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusSerum amino-acid ratio63Children with kwashiorkor generally have serum NEAA:EAA ratios above 3

Normal children and those with marasmus, ratios are usually less than 2Serum amino-acid ratio64Amino Acid Ratio (NEAA:EAA) =glycine + serine + glutamine + taurineisoleucine + leucine +valine + methionine Interpretative guidelines for serum non-essential: essential amino acid ratios65Source : Gibson, 1991ParameterLess than acceptableAcceptable (low risk)Deficient (high risk)Low (medium risk)Nonessential : essential amino acid ratio> 3.02.0 3.0< 2.0Protein status66Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusUrinary 3-hydroxyproline excretion67Urinary 3-hydroxyproline is an excretory product derived from the soluble and insoluble collagens of both soft and calcified tissues

Hydroxyproline:creatinine ratio (corrects for differences in adult body size)Hydroxyproline (mg) per 24 hourCreatinine (mg) per 24 hourUrinary 3-hydroxyproline excretion68Hydroxyproline index

Hydroxyproline =indexMg hydroxyproline per mL urine x kg body weight_____________mg creatinine per mL urineInterpretative guidelines for urinary hydroxyproline index69Source : Gibson, 1991ParameterLess than acceptableAcceptable (low risk)Deficient (high risk)Low (medium risk)Hydroxyproline index (3 months to 10 years of age> 1.01.0 2.0> 2.0Protein status70Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusNitrogen balance71measure of net changes in total body protein massProtein status72Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusUrinary urea nitrogen: creatinine ratios73Urea is the largest source of urinary nitrogen and is synthesized in the liverUrinary urea nitrogen:creatinine ratios are used as an index of dietary protein intake but not an index of long-term protein statusInterpretative guidelines for urinary urea nitrogen:creatinine ratios74Source : Gibson, 1991ParameterLess than acceptableAcceptable (low risk)Deficient (high risk)Low (medium risk)Urea nitrogen : creatinine ratio< 6.06.0 12.0> 12.0Protein status75Urinary creatinine excretion3-methylhistidine excretionSerum proteinsSerum albuminSerum transferrinSerum retinol-binding proteinSerum thyroxine-binding pre-albuminSerum somatomedin-CSerum amino-acid ratioUrinary 3-hydroxyproline excretionNitrogen balanceUrinary urea nitrogen: Creatinine ratiosFunctional tests of protein statusFunctional tests of protein status 76Include muscle function and immunological tests

Muscle function measure changes in muscle contractility, relaxation rate, endurance, and hand grip strength

Immunological tests include lymphocyte count, delayed cutaneous hypersensitivity, measurement of thymus-dependent lymphocytes, and lymphocyte nitrogen assaysAssessment of Nutritional StatusBiochemical assessment77Biochemical measurements of selected nutrients78ProteinIronVitamin AVitamin DVitamin EVitamin CThiamineRiboflavinNiacinVitamin B6FolateVitamin B12CalciumPhosphorusMagnesiumIodineLipid and glucoseZinc

Iron79Total body composition of iron in adults: 3 5 grams elemental ironFound in three components:Essential ironTransport ironStorage ironIron80Essential ironin RBC (70%)in myoglobin (4%)in enzymes ( 160< 200< 110Borderline200 239130 159135 139200 239110 125High> 240>160-> 400> 125Low--< 135Biochemical measurements of selected nutrients237ProteinIronVitamin AVitamin DVitamin EVitamin CThiamineRiboflavinNiacinVitamin B6FolateVitamin B12CalciumPhosphorusMagnesiumIodineLipid and glucoseZinc

Zinc status238Hair zincSerum zincHair zinc239Low hair zinc concentrations were reported in the first documented cases of human zinc deficiency in young adult male dwarfs from the middle East (Strain et al., 1966)Hair zinc240Hair zinc concentrations probably reflect a chronic suboptimal zinc status when the confounding effect of severe PEM is absentStandardized procedure for sampling, washing and analyzing hair samples are essentialHair zinc241Collected from close to the occipital portion of the scalp with stainless steel scissors, and only the proximal 1.0 1.5 cm of the hair strands retained from analysisAny nits and lice must be removed before washing the hair samples using a standardized methodHair zinc242A non-ionic detergent ( e.g. Actinox) with or without acetone is often usedZinc status243Hair zincSerum zincSerum zinc24412-22% of zinc in the blood is in the serum, the rest is within the erythrocyteTransported in three serum bound to proteinsAlbumin (70%) 2-macroglobulin (18%)Rest other proteins like transferrin and ceruloplasmin and to amino acids (histidine and cysteine)245

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The State of the Nations NUTRITION

Source: FNRI, 2008247

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BiochemicalAssesses the prevalence of:Iron deficiency anemia,Vitamin A deficiency, and Iodine deficiency disordersZinc, folate and Vitamin B6 was done for the first time252Public health significance problemVitamin A deficiencyMore than 15% serum or plasma retinol of