Assessment of Nutritional Status Biochemical assessment 1.

Assessment of Nutritional Status Biochemical assessment 1

2 Involves measurement of nutrient levels or their metabolites in body tissues or fluids Estimation of tissue desaturation, enzyme activity or blood composition

Biochemical assessment 3 Tests are confined to 2 easily obtainable fluids namely blood and urine and results are generally compared to standards Results are generally compared to standards, i.e. normal levels for age and sex

Biochemical assessment 4 An objective method of nutritional assessment Provides specific information on the bodys status regarding specific nutrients and may also identify borderline nutritional deficiencies or excesses Can be used to assess the nutritional status of large population groups

Advantages 5 Objectivity Independent of the emotional and subjective factors that usually affect the investigator Free from bias compared to other methods of nutritional status

Advantages 6 Can detect early subclinical states of nutritional deficiency Can identify nutritional deficiency before appearance of clinical signs Reveals nutrient deficiency at an early stage

Advantages 7 Can confirm existence of abnormality, since clinical signs are non-specific Precision and accuracy

Disadvantages 8 Costly, usually requiring expensive equipments Time consuming Difficult to collect samples Lack of practical standards of sample collection

Objectives 9 1. To 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 2. 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 reveal

Factors affecting accuracy of results 10 1. Method of sample collection 2. Method of transport and storage of samples 3. Technique employed

Ideal Biochemical Tests 11 1. Specific 2. Simple 3. Inexpensive 4. Reveal tissue depletion at an early stage 5. Require less sophisticated equipment and skill

Common biochemical parameters/tests 12 FluidParameterNutritional deficiency BloodSerum albuminProtein deficiency Amino acid imbalanceProtein deficiency Serum vitamin AVitamin A deficiency Serum caroteneVitamin A deficiency Serum alkaline phosphataseVitamin D deficiency Serum ascorbic acidVitamin C deficiency HemoglobinIron and Vitamin B12 deficiency HematocritIron deficiency UrineHydroxyproline excretionProtein deficiency Urinary ureaProtein deficiency Urinary creatinineProtein deficiency Urinary thiamineThiamine deficiency Urinary ribiflavinRiboflavin deficiency

Choosing the biochemical assessment method 13 1. Direct measurement of the nutrient a. Serum proteins (albumin, globulin, fibrinogen, carrier proteins) b. Blood glucose c. Blood lipids : free fatty acids, total cholesterol, LDL-cholesterol, triglycerides d. Serum retinol, ascorbic acid, calcium, sodium, B-vitamins

Choosing the biochemical assessment method 14 2. Measurement of substances that indirectly reflect level of the nutrient in the body a. Hematocrit, hemoglobin b. Hormones (e.g. Thyroid hormones) c. Binding proteins (e.g. Retinol binding proteins) d. Urinary excretion of metabolites (iodine, B6 deficiency: increased excretion of xanthurenic acid, other tryptophan metabolites)

Choosing the biochemical assessment method 15 3. Know the physiology and metabolism of the nutrient to be measured a. Is it a water or fat soluble nutrient? b. Can it be stored by the body in significant amounts? c. How are levels of the nutrient in the body regulated? d. What are the normal roles of the nutrient in the body? e. What will likely happen if the nutrient becomes deficient?

What is the biological sample to be used? 16 1. Blood 2. Urine

Blood 17 Arterial, venous, plasma, serum, blood cells erythrocytes Measurements of nutrients/ metabolites are often controlled by homeostasis tend to reflect recent intake

Blood 18 Random sample Taken at any time of the day Depending on what is being measured, may be influenced by recent food intake, physical activity, fluid intake

What is the biological sample to be used? 19 1. Blood 2. Urine

Urine 20 1. First voided morning urine sample Assumed that subjects have been asleep for the past 6-8 hours No food and fluid intake immediately before sample taken Physical activity standardized between different subjects

Urine 21 2. 24-hour sample More difficult to make a complete collection, especially in free-living subjects

Mid-stream sample 22 Breastmilk, saliva, sweat, adipose tissues, feces, hair and nails, buccal mucosal cells

Preservation of biological samples 23 Any separation/initial processing required Containers for storage and transport Considerations (cold storage, transport) It is of utmost importance to preserve the integrity of the collected samples prior to actual analysis in the laboratory

Assay 24 Analysis 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 samples 25 Methods to be used in analysis 1. Spectrophotometry 2. Immunological methods 3. Chromatography

Spectrophotometry 26 Based on the principle that different substances have different characteristics with regard to light spectrum

Immunological methods 28 Radioimmunoassay, enzyme immunoassay methods, based on the principle that substances have specific ability to bind to certain antigens/antibodies

Chromatography 30 Gas chromatography, HPLC-based on the principle that substances have differences in chemical characteristics (mol wt) that allow then to be isolated from each other

Analysis of biological samples 31 Equipment required for analysis Are they available? Is the procedure being done locally? Is there a laboratory person technically trained to perform the procedure?

Analysis of biological samples 32 Coordination of sample collection, storage and transport Techniques for collection of samples Informed consent from subjects Methods vary in cost, reliability, degree of technical expertise required

Interpretation of results 33 1. Low nutrient levels a. Dietary deficiency b. Poor absorption c. Impaired transport d. Abnormal utilization e. Combination of factors

Interpretation of results 34 2. Compare individual results with normal reference values appropriate for: a. Age b. Sex c. Physiological state

Biochemical measurements of selected nutrients 35 1. Protein 2. Iron 3. Vitamin A 4. Vitamin D 5. Vitamin E 6. Vitamin C 7. Thiamine 8. Riboflavin 9. Niacin 10. Vitamin B6 11. Folate 12. Vitamin B12 13. Calcium 14. Phosphorus 15. Magnesium 16. Iodine 17. Lipid and glucose 18. Zinc

Protein status 36 Laboratory indices of protein status measure somatic protein status, visceral protein status, metabolic changes, muscle function and immune function

Protein status 37 Proteins-body stores are determined from by-products of protein catabolism and products of protein synthesis

Protein status 38 1. Urinary creatinine excretion 2. 3-methylhistidine excretion 3. Serum proteins 4. Serum albumin 5. Serum transferrin 6. Serum retinol-binding protein 7. Serum thyroxine-binding pre-albumin 8. Serum somatomedin-C 9. Serum amino-acid ratio 10. Urinary 3-hydroxyproline excretion 11. Nitrogen balance 12. Urinary urea nitrogen: Creatinine ratios 13. Functional tests of protein status

Urinary creatinine excretion 39 Used 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 made Frequently expressed as creatinine height index

Guidelines for the interpretation of creatine height index 40 Less 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> 0.9 Source : Gibson, 1991

Factors affecting daily creatinine excretion 41 1. Strenuous exercise 2. Emotional stress 3. Dietary intakes of creatine and creatinine 4. Menstruation 5. Age 6. Infection, fever and trauma 7. Chronic renal failure

3-Methylhistidine excretion 43 3-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 used

Serum proteins 45 Index of visceral protein status Easily measured but a rather insensitive index of protein status

Factors affecting serum protein concentrations 46 1. Inadequate protein intake 2. Altered metabolism 3. Specific deficiency of plasma protein 4. Reduced protein synthesis 5. Pregnancy 6. Capillary permeability 7. Drugs 8. Strenuous exercise

Guidelines for the interpretation of total serum protein concentrations, g/dL 47 Subjects Less than acceptable Acceptable (low risk) Deficient (high risk) Low (medium risk) Infants 0-11 months-< 5.0> 5.0 Children 1 to 5 years-< 5.5> 5.5 Children 6 to 17 years-< 6.0> 6.0 Adults< 6.06.0 to 6.4> 6.5 Pregnant, 2 nd and 3 rd trimester < 5.55.5 to 5.9> 6.0 Source : Sauberlich et al, 1974

Serum albumin 49 Reflects changes occurring within the intravascular space and not the total visceral protein pool Not very sensitive to short-term changes in protein status Has a long half-life of 14 to 20 days

Interpretative guidelines for serum albumin concentrations, g/dL 50 Subjects Less than acceptable Acceptable (low risk) Deficient (high risk) Low (medium risk) Infants 0-11 months-< 2.5> 2.5 Children 1 to 5 years< 2.8< 3.0> 3.0 Children 6 to 17 years< 2.8< 3.5> 3.5 Adults< 2.82.8 to 3.4> 3.5 Pregnant 1 st trimester< 3.03.0 to 3.9> 4.0 Pregnant, 2 nd and 3 rd trimester< 3.03.0 to 3.4> 3.5 Source : Gibson, 1991

Serum transferrin 52 Transferrin is a serum beta-globullin protein synthesized primarily in the liver and is located almost totally intravascularly Serves as the iron transport protein Is bacteriostatic (binds with free iron and prevents the growth of gram- negative bacteria which require iron for growth)

Interpretative guidelines for serum transferrin, ug/L 53 ParameterProtein deficit NoneMildModerateSevere Transferrin> 200150 - 200100 - 150< 100 Source : Gibson, 1991

Serum retinol-binding protein 55 is a carrier protein for retinol Serum RBP concentrations tend to fall rapidly in response to protein and to energy deprivation and respond quickly to dietary treatment

Interpretative guidelines for retinol- binding protein 56 ParameterProtein deficit NoneMildModerateSevere Retinol- binding protein (mg/dL) 2.6 7.6--- Source : Gibson, 1991

Serum thyroxine-binding pre- albumin 58 TBPA serves as transport protein for thyroxine and as a carrier protein for RBP More sensitive index of protein status and responds more rapidly to dietary treatment

Interpretative guidelines for thyroxine-binding pre-albumin 59 ParameterProtein deficit NoneMildModerateSevere Thyroxine- binding pre- albumin (mg/dL) 15.7 29.610 - 155 - 10< 5 Source : Gibson, 1991

Serum somatomedin-C 61 Somatomedins are growth-hormone dependents serum growth factors produced by the liver Circulate blood to carrier proteins and have a half-life for several hours More sensitive to acute changes in protein status than the other serum proteins

Serum amino-acid ratio 63 Children with kwashiorkor generally have serum NEAA:EAA ratios above 3 Normal children and those with marasmus, ratios are usually less than 2

Serum amino-acid ratio 64 Amino Acid Ratio (NEAA:EAA) = glycine + serine + glutamine + taurine isoleucine + leucine + valine + methionine

Interpretative guidelines for serum nonessential: essential amino acid ratios 65 Source : Gibson, 1991 Parameter Less than acceptable Acceptable (low risk) Deficient (high risk) Low (medium risk) Nonessential : essential amino acid ratio > 3.02.0 3.0< 2.0

Urinary 3-hydroxyproline excretion 67 Urinary 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 hour Creatinine (mg) per 24 hour

Urinary 3-hydroxyproline excretion 68 Hydroxyproline index Hydroxyproline = index Mg hydroxyproline per mL urine x kg body weight_____________ mg creatinine per mL urine

Interpretative guidelines for urinary hydroxyproline index 69 Source : Gibson, 1991 Parameter Less than acceptable Acceptable (low risk) Deficient (high risk) Low (medium risk) Hydroxyproline index (3 months to 10 years of age > 1.01.0 2.0> 2.0

Nitrogen balance 71 measure of net changes in total body protein mass

Urinary urea nitrogen: creatinine ratios 73 Urea is the largest source of urinary nitrogen and is synthesized in the liver Urinary urea nitrogen:creatinine ratios are used as an index of dietary protein intake but not an index of long-term protein status

Interpretative guidelines for urinary urea nitrogen:creatinine ratios 74 Source : Gibson, 1991 Parameter Less than acceptable Acceptable (low risk) Deficient (high risk) Low (medium risk) Urea nitrogen : creatinine ratio < 6.06.0 12.0> 12.0

Functional tests of protein status 76 Include 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 assays

Assessment of Nutritional Status Biochemical assessment 77

Iron 79 Total body composition of iron in adults: 3 5 grams elemental iron Found in three components: 1. Essential iron 2. Transport iron 3. Storage iron

Iron 80 1. Essential iron a. in RBC (70%) b. in myoglobin (4%) c. in enzymes (

Criteria for assessing goiter Total goiter rate (%)Severity of IDD < 5.0 Normal 5.0 19.9Mild 20.0 29.9Moderate > 30.0Severe Sources: Indicators for assessing IDD and their control through salt iodization. Geneva, World Health Organization, 1994 223

In summary The iodine status of children, 6-12 years old, 13-19 years old and adults, 20-59 years and 60 years and over are optimal as indicated by median UIE levels The iodine status of pregnant and lactating women of public health concern 224

Laboratory tests for iodine status 225 1. Urinary iodine excretion 2. Serum thyroxine (T4) 3. Blood levels of TSH 4. Radioactive iodine uptake levels 5. Protein bound iodine in blood plasma

Serum thyroxine (T4) 226 Measure of thyroid function If low is an evidence of poor thyroid function, which may be related to goiter

Blood levels of TSH 228 Blood is taken from the umbilical cord or heel of all infants born in hospital and sent on filter paper to a special laboratory for determination of thyroxine or TSH Test is done because about one in 4,000 infants born is hypothyroid because the thyroid gland did not develop properly

Blood levels of TSH 229 If the condition is not diagnosed and treated soon after birth, there will be serious consequences, including poor brain development Generally, T4 levels below 4 g percent are considered low, requiring treatment

Blood levels of TSH 230 As with urinary iodine, few hospitals in most developing countries are equipped to do T4 and TSH concentrations

Radioactive iodine uptake levels 232 Usually using l131 to assess the avidity or hunger of the subjects thyroid gland for iodine In persons with hypothyroidism caused by iodine deficiency, most of the dose of iodine is taken up by the thyroid gland, and less than 10 percent remains

Protein Bound Iodine (PBI) in blood plasma 234 Widely used test in the past

Blood lipids and Fasting Blood Sugar or Glucose classification 236 Classification Total cholesterol (mg/dL) LDL- cholesterol (mg/dL) HDL- cholesterol (mg/dL) Triglycerides (mg/dL) FBS or glucose (mg/dL) Desirable< 200< 130> 160< 200< 110 Borderline200 239130 159135 139200 239110 125 High> 240>160-> 400> 125 Low--< 135

Zinc status 238 1. Hair zinc 2. Serum zinc

Hair zinc 239 Low 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 zinc 240 Hair zinc concentrations probably reflect a chronic suboptimal zinc status when the confounding effect of severe PEM is absent Standardized procedure for sampling, washing and analyzing hair samples are essential

Hair zinc 241 Collected 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 analysis Any nits and lice must be removed before washing the hair samples using a standardized method

Hair zinc 242 A non-ionic detergent ( e.g. Actinox) with or without acetone is often used

Zinc status 243 1. Hair zinc 2. Serum zinc

Serum zinc 244 12-22% of zinc in the blood is in the serum, the rest is within the erythrocyte Transported in three serum bound to proteins 1. Albumin (70%) 2. 2-macroglobulin (18%) 3. Rest other proteins like transferrin and ceruloplasmin and to amino acids (histidine and cysteine)

The State of the Nations NUTRITION Source: FNRI, 2008 247

Biochemical 250

Biochemical Assesses the prevalence of: Iron deficiency anemia, Vitamin A deficiency, and Iodine deficiency disorders Zinc, folate and Vitamin B6 was done for the first time 252

Public health significance problem Vitamin A deficiency More than 15% serum or plasma retinol of

Assessment criteria

Thank You janicepaladfeliciano 255

11 March (Tue) 256 Quiz on Biochemical assessment (both lecture and laboratory) Planning a community nutrition survey Overview Steps in the conduct of survey

Assessment of Nutritional Status Biochemical assessment 1.

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