Definitions
Estimated Average Requirements(EAR) are
expected to satisfy the needs of 50% of the
people in that age group based on a review of the
scientific literature.
Recommended Daily Allowance(RDA) is the
daily intake level of a nutrient which is considered
sufficient by the food and Nutrition board to meet
the requirements of 97.5% of healthy individuals
in each life-stage and sex group . It is calculated
based on EAR and is usually approximately 20%
The RDA is used to determine the
Recommended Daily Value(RDV) which is
printed on food labeles in the U.S.A. and
Canada.
Adequate Intake(AI) is used where no
RDA has been established , but the
amount established is somewhat less
firmly believed to be adequate for
everyone in the demographic group.
Nutrition Care Process (NCP):
 Defined as “a systemic problem-solving method that
dietetic professionals use to critically think and make
decisions to address nutrition -related problems and
provide safe and effective quality nutrition care.”
 There are four components to the NCP:
1. nutrition assessment.
2. nutrition diagnosis.
3. nutrition intervention.
4. nutrition monitoring and evaluation.
Nutrition assessment includes:
A. Anthropometric or body composition measurements.
B. Biochemical analyses.
C. Clinical examination usually performed by the
physician or other health care provider.
D. Dietary analysis and assessment to determine
usual food intake generally performed by the registered
dietitian (RD).
E. Environmental assessment.
Nutrition assessment
A. Anthropometric measurements:
• Include the measurement of height and weight and,
the calculation of the body mass index [BMI] .
• BMI: “used to assess overweight and obesity and to
monitor changes in body weight.”
• Other measurements include a weight history, and
possibly a waist circumference measurement.
Nutrition assessment
B. Biochemical assessment/markers:
• The macronutrients include markers of carbohydrate,
protein, and fat metabolism and utilization.
• Micronutrients measurements include vitamins,
minerals and trace elements are often the more
difficult to obtain.
Nutrition assessment
C. The clinical component of the nutrition assessment:
• Consists of the history of present illness, the past
medical history, and an inquiry into the family history.
• It includes a measurement of blood pressure as
well as presence of any physical limitations/restrictions
regarding physical movement/activity.
• For example, the review of systems (ROS) is a head totoe examination looking for signs of malnutrition
and/or disease
Nutrition assessment
D. The dietary component of the nutritional assessment:
• Determine the adequacy of the usual day’s intake with
respect to nutritional recommendations that are specific
for an individual’s age, gender, level of physical
activity, and particular health conditions.
E. The environmental assessment:
• Takes into consideration all aspects of an individual’s
environment or living conditions that may affect his or
her ability to purchase, prepare, and/or consume food.
The information obtained from all A–E
aspects of a complete nutrition assessment are then
summarized and reviewed by the RD or other health
care professional to determine: Nutrition diagnosis,
 Nutrition intervention
implemented,
is
designed
 Followed by monitoring and evaluation
and
BIOCHEMICAL MARKERS
A. Macronutrients
1. Proteins:
 Laboratory nutritional assessment is best accomplished
by monitoring selected serum proteins.
 The concentration of protein markers of malnutrition
are affected by protein malnutrition associated with endstage liver and renal disease and severe infection.
 A separation of the inflammatory state from protein
malnutrition can be problematic.
A.Macronutrients
A.Macronutrients
2. Albumin
 Assessment of hospitalized patients.
 Influenced by albumin synthesis, degradation, and
distribution.
• Low albumin levels have been identified as a predictor
of mortality in patients in long-term-care facilities.
• Albumin has been used to help determine two
important nutritional states:
1. First; chronic protein deficiency under conditions of
adequate non protein-calorie intake (hypoalbuminemia).
1. Second; albumin concentrations may help define marasmus
“energy deficiency”. The serum albumin level remains
normal but there is considerable loss of body weight.
A.Macronutrients
3. Transferrin
o Transferrin is a glycoprotein,
synthesized in the liver
and binds and transports
ferric iron
o It is an early indicator of iron deficiency, and the elevated
transferrin is the last analyte to return to normal when
iron deficiency is corrected.
A.Macronutrients
4. Transthyretin
 In normal situations, each transthyretin subunit
contains
one binding
site for retinol-binding protein (RBP)
"major transport proteins for thyroxine and vitamin
A".
 Transthyretin is a better indicator of visceral protein status
and positive nitrogen
balance
than albumin and
transferrin (because of its short half-life and small body
pool).
 The concentration of transthyretin and RBP complex,
greatly decreased in protein-energy malnutrition.
A.Macronutrients
5. Retinol-Binding Protein
 Used in monitoring shortterm changes in nutritional
status.
 Although RBP has a shorter half-life than transthyretin
(12 hours, compared with 2 days), it is excreted in urine,
and its concentration increases more significantly than
transthyretin in patients with renal failure.
 When decreases to levels of less than 80 mg/L, severe
protein-calorie malnutrition develops; however, nutritional
support can cause a daily increase of up to 10 mg/L.
A.Macronutrients
6. Insulin Growth Factor I
 Formerly termed somatomedin C, is
important for stimulation of growth.
 Growth hormone stimulates the liver to produce IGF-1,
which circulates bound to IGF-BP3.
 IGF-I used as a nutritional marker in adults and children.
A.Macronutrients
7. Fibronectin
Is an a2-glycoprotein that serves important roles in cell-tocell adherence and tissue differentiation, wound healing,
microvascular integrity, and opsonization.
It
is
considered
phagocytosis.
the
major
protein regulating
Fibronectin
concentrations
may decrease
after
physiologic damage caused by severe shock, burns, or
infection.
A.Macronutrients
8. Nitrogen Balance
 Nitrogen balance, is the
difference between nitrogen
intake and nitrogen excretion.
 During
stress, trauma,
decreases.
or burns, the nutritional intake
 And due to an increase in catabolism, nitrogen losses
increase and may exceed intake, leading to a negative
nitrogen balance.
A.Macronutrients
9. C-Reactive Protein
 C-reactive protein is an acute-phase protein that
increases dramatically under conditions of sepsis,
inflammation, and infection.
 The flow phase of marked catabolism presents
clinically with tachycardia, fever, increased respiratory
rate, and increased cardiac output.
 During this time, synthesis rates of C-reactive protein
and other acute-phase proteins increase and albumin
and pre-albumin decrease.
 This produces weight loss with decreased albumin and
prealbumin levels.
A.Macronutrients
10. Interleukins
 Most nutritional investigations have been performed on
interleukin-1 (IL-1), IL-6, and tumor necrosis factor(TNF).
A.Macronutrients
11. Total Parenteral Nutrition (TPN)
o Parenteral nutrition therapy involves administering
appropriate amounts of carbohydrate,
amino acid, and
lipid solutions, as well as electrolytes, vitamins, minerals,
and trace elements, to meet the caloric, protein, and nutrient
requirements while maintaining water
and electrolyte
balance.
o Because TPN
administration
bypasses
normal
absorption and circulation routes, careful laboratory
monitoring of these patients is critical.
The Eat-Well Plate
B. Carbohydrates
1. Urine Testing
• In small premature infants, glycosuria during the early phase
of TPN is a signal that glucose infusion is too rapid.
2. Tests to Monitor Electrolyte Disturbances
• Sodium regulation is a problem in children during TPN.
• Factors that increase the amount of sodium necessary to
maintain normal serum sodium concentrations in both
children and adults are glycosuria, diuretic use, diarrhea
or other excessive gastrointestinal losses, and increased
postoperative fluid losses.
C.Micronutrients
Vitamins
 Chemical determination of human vitamin states has been
approached in the following ways:
• Measurement of active cofactors or precursors in biologic fluids
or blood cells.
• Measurement of urinary metabolites of the vitamin.
• Measurement of a biochemical function requiring the vitamin
(e.g., enzymatic activity).
• Measurement of urinary excretion of vitamin or metabolites
after a test load of the vitamin.
• Measurement of urinary metabolites of a substance, the
metabolism of which requires the vitamin after administration
of a test load of the substance.
C.Micronutrients
Vitamins are classified into tow main categories:
1- Fat-soluble vitamins
2- Water-soluble vitamins.
 Fat-Soluble Vitamins
1. Vitamin A “Retinol”
• Retinol and retinoic acid are derived
directly from dietary sources.
• Major dietary sources include animal products, pigmented
fruits and vegetables (carotenoids).
• Vitamin A deficiency leads to night blindness.
• Epithelial cells become dry and keratinized.
• Excess vitamin A causes many toxic manifestations and may
ultimately lead to liver damage.
• Commonly measured by high-performance
chromatography
(HPLC).
liquid
 Fat-Soluble Vitamins
2. Vitamin E “Tocopherol”
• Vitamin E is a powerful antioxidant and the primary defense
against potentially harmful oxidations that cause disease
and aging.
• Dietary sources include vegetable oil, fresh leafy vegetables,
egg yolk, legumes, peanuts, and margarine
• The major role of vitamin E is protecting the erythrocyte
membrane from oxidant stress.
• The major symptom of vitamin E deficiency is
hemolytic anemia.
• Patients with conditions that result in fat malabsorption,
especially cystic fibrosis and abetalipoproteinemia, are also
susceptible to vitamin E deficiency.
 Fat-Soluble Vitamins
3. Vitamin D
• Used for proper skeleton formation and
mineral homeostasis.
• It stimulates intestinal absorption of calcium and phosphate
for bone growth and metabolism.
• Major dietary sources include irradiated foods and
commercially prepared milk. Small amounts are found in
butter, egg yolks, liver, sardines, herring, tuna, and salmon.
• Severe deficiency in children lead to the development of
rickets.
• In adults, the deficiency leads to under-mineralization
of bone matrix in remodeling, resulting in osteomalacia.
 Fat-Soluble Vitamins
4. Vitamin K “koagulation”
• Essential for the formation of prothrombin and at least five
other coagulation proteins, including factors VII, IX, and X
and proteins C and S.
• Vitamin K is synthesized by intestinal bacteria, 50%;
dietary sources are cabbage, cauliflower, spinach and other
leafy vegetables, liver, soybeans, and vegetable oils.
• Vitamin K deficiency may be caused
by antibiotic therapy
• Both PT and APTT are prolonged in vitamin K deficiency.
• In most laboratories, vitamin K is not assayed; however, PT is
used as a functional indicator of vitamin K status.
 Water-Soluble Vitamins
1. Thiamine (vitamin B1)
• Acts as a coenzyme in decarboxylation
reactions in major carbohydrate pathways.
• Absorbed from food in the small intestine
and excreted in the urine.
• Chronic thiamine deficiency lead to beriberi. “I can’t ..I
can’t”
• Decreased intake, impaired absorption, and increased
requirements all appear to play a role in the development of
thiamine deficiency in persons with alcoholism.
• Thiamine functional activity is best measured by erythrocyte
transketolase (ETK) activity, before and after the addition of
thiamine pyrophosphate (TPP).
 Water-Soluble Vitamins
2. Riboflavin (vitamin B2)
 A component of
two
coenzymes, flavin
mononucleotide and flavin adenine dinucleotide
(FAD).
 Catalyze various oxidation-reduction reactions.
 Absorbed in the small intestine and excreted in the urine.
 Found in milk, liver, eggs, meat, and leafy vegetables.
 Riboflavin deficiency occurs with other nutritional deficiencies,
alcoholism, and chronic diarrhea and malabsorption.
 Reduced glutathione reductase activity greater than 40% is an
indication of deficiency.
 Water-Soluble Vitamins
3. Pyridoxine (vitamin B6)
 Vitamin B6 is three related compounds:
pyridoxine, occurring mainly in plants;
and pyridoxal and pyridoxamine, which
are present in animal products.
 Readily absorbed from the intestinal tract, and excreted in the
urine in the form of metabolites.
 Vitamin B6 deficiency more commonly seen in patients
deficient in several B vitamins.
 Those particularly at risk for deficiency are patients with
uremia, liver disease, absorption syndromes, malignancies, or
chronic alcoholism.
 Water-Soluble Vitamins
4. Niacin (Vitamin B3)
 The requirement for niacin in humans is
met, to some extent, by the conversion of
dietary tryptophan to niacin.
 Niacin functions as a component of the
two coenzymes (NAD) and (NADP) “eg;
lipid and fatty acid metabolism”.
 Pellagra, the clinical syndrome
resulting from niacin
deficiency,
is
associated
with
diarrhea,
dementia,
dermatitis, and death.
 To decrease lipid levels, pharmacologic doses of nicotinic acid are
given therapeutically
 Water-Soluble Vitamins
5. Folate
 Act as coenzymes in various one-carbon
transfer reactions.
 Absorbed in the jejunum, and the
excess is excreted in the urine and feces.
 Large quantities of folate are also
synthesized by bacteria in the colon.
 Boiling food and using large quantities
of water result in folate destruction.
 The major clinical symptom of folate deficiency is megaloblastic
anemia.
 Water-Soluble Vitamins
Folate Cont. ….
 Chemical indices of deficiency are in order of occurrence, low
serum folate, hypersegmentation of neutrophils, low erythrocyte
folate, macro-ovalocytosis, megaloblastic marrow, and anemia.
 Folate requirement is increased during pregnancy and especially
during lactation.
 Supplementation of folate in pregnant women reduces the
incidence of fetal neural tube defects.
 Increased folate requirement include hemolytic anemia, iron
deficiency, prematurity, and multiple myeloma.
 Folate levels may be measured in serum using a microbiologic
assay with Lactobacillus casei or a competitive proteinbinding assay for levels in serum and erythrocytes.
 Water-Soluble Vitamins
6. Vitamin B12
o Vitamin B12 (cobalamin) refers to a large
group of cobaltcontaining compounds.
o Intestinal absorption of vitamin B12
takes
place in the ileum and is mediated by a unique
binding protein called intrinsic factor, which
is secreted by the stomach.
o The primary dietary source for vitamin B12 are from animal
products (e.g., meat, eggs, and milk).
o The average daily diet contains 3–30 µg of vitamin B12, of which
1–5 µg is absorbed.
o The term pernicious anemia is now most commonly
applied to vitamin B12 deficiency resulting from lack of
intrinsic factor.
 Water-Soluble Vitamins
Vitamin B12 Cont. …..
 Deficiency of B12 can occasionally
occur in strict vegetarians because of
dietary deficiency of B12.
 also occurs in individuals infected with
fish tapeworm or because of
malabsorption diseases, such as sprue
or celiac disease.
 Deficiency
of vitamin B12 causes
two major disorders
megaloblastic anemia (pernicious anemia) and a neurologic
disorder called combined systems disorder.
 The most common methods for determination of vitamin B12
are the competitive protein-binding RIAs.
 Water-Soluble Vitamins
7. Biotin (Vitamin B7)
 Biotin is a coenzyme for several enzymes that
transport carboxyl units in tissue and plays an
integral role in gluconeogenesis, lipogenesis, and
fatty acid synthesis.
 Dietary biotin is absorbed in the small intestine,
but it is also synthesized in the gut by bacteria.
 Biotin deficiency can be produced by ingestion of large
amounts of avidin, found in raw egg whites that bind to biotin.
 Biotin deficiency has been noted in patients receiving
long-term parenteral nutrition and in infants with genetic defects
of carboxylase and biotinidase enzymes.
 Water-Soluble Vitamins
 Assays had been performed using microbiology functional assay
and
the
Lactobacillus
organism,
isotopic
dilution,
chemiluminescent, and photometric assays.
8. Pantothenic Acid (from Greek for “everywhere”)
 A growth factor occurring in all types of animal and plant tissue
was first designated vitamin B3 and later named pantothenic
acid.
 Dietary sources include liver and other organ meats, milk, eggs,
peanuts, legumes, mushrooms, salmon, and whole grains.
 Pantothenate is metabolically converted to 4-phosphopantetheine,
which becomes covalently bound to either serum acyl carrier
protein or coenzyme A.
 Water-Soluble Vitamins
9. Ascorbic Acid (Vitamin C)
• A strong reducing compound that has to be
acquired via dietary ingestion.
• Major dietary sources include fruits (especially
citrus) and vegetables (e.g., tomatoes, green
peppers, cabbage, leafy greens, and potatoes).
• Important in formation and stabilization
of collagen, and
increases the absorption of certain minerals, such as iron.
• The deficiency state, known as scurvy, is characterized by
hemorrhagic disorders, including swollen, bleeding gums and
impaired wound healing and anemia.
 Water-Soluble Vitamins
Ascorbic Acid
Cont. …..
• Drugs known to increase urinary excretion of ascorbate
include aspirin, aminopyrine, and others.
• Ascorbic acid requirements are more increased with acute
stress injury and chronic inflammatory states, but are also
increased with pregnancy and oral contraceptive use.
• Excessive intake
metabolism.
may
interfere
with
vitamin
B12
• The most widely used assay for ascorbic acid is the
2,4-dinitrophenylhydrazine method. In this procedure,
ascorbic acid is first oxidized to dehydroascorbic acid
and 2,3-diketogulonic acid with the formation of a colored
product that absorbs at 520 nm. HPLC has been developed to
give increased sensitivity and specificity.
 Water-Soluble Vitamins
10. Carnitine
• Meat, poultry, fish, and dairy products are the
major dietary sources. Foods of plant origin
generally contain little carnitine, except
for peanut butter and asparagus.
• Synthesis occurs in liver, brain, and kidney.
• L-Carnitine facilitates entry of long-chain fatty acids into
mitochondria for oxidation and energy production.
• The major signs of
weakness and fatigue.
carnitine
deficiency
are
muscle
• Human deficiency can be either hereditary or acquired—by
inadequate intake, increased requirement (pregnancy and
breastfeeding), or increased urinary loss (valproic acid
therapy).
 Mineral metabolism - Calcium/phosphorus
 Mineral Tests to Monitor
I.
One of the most important aspects of TPN monitoring is
determining deficiencies and excesses of calcium,
phosphorus, and magnesium.
II. Calcium is present in serum in two forms: protein bound,
or non-diffusible, and ionized diffusible calcium
(physiologically active).
III. Decreased ionized calcium often is caused by an increase in
blood pH (alkalosis).
IV. It is important to monitor ionized serum calcium and blood
pH, especially in a patient on TPN.
 Mineral metabolism - Calcium/phosphorus
 Mineral Tests to Monitor Cont. …..
V. Intracellular phosphate is necessary to promote protein
synthesis and other cellular functions.
VI. Severe hypophosphatemia has been reported in patients
undergoing prolonged TPN.
VII.Low levels of magnesium can cause tetany, whereas high
levels can increase cardiac atrioventricular conduction
time.
 Trace Minerals / Trace Elements to Monitor
1. Copper
 Copper is a component of
1. Cytochrome oxidase enzyme (ATP generation).
2. Dopamine monooxygenase (neuron activity and transmission
of impulse).
3. Superoxide dismutase (reduce the free radical superoxide).
4. Ceruloplasmin (convert iron from the Fe+3 state to the
absorbed Fe+2).
 The diagnosis of copper deficiency is confirmed when both serum
copper and ceruloplasmin (the copper binding glycoprotein) are
low.
 Trace Minerals / Trace Elements to Monitor
1. Copper Cont. ……
 Low copper levels have also been reported in malabsorption
syndrome, protein-wasting intestinal diseases, nephrotic
syndrome, severe trauma, anemia, and burns.
 The accumulation of copper in the liver can go into hepatitis,
then a fibrosis, and then a cirrhosis if not treated with chelation
and diet restricted in copper content.
 Methods for copper measurement include atomic absorption
for serum and urinary copper measurements. Indirect
copper measurements are attained by measuring the
ceruloplasmin levels.
 Trace Minerals / Trace Elements to Monitor
2. Zinc
 Metalloenzymes using zinc include carbonic anhydrase,
alkaline phosphatase (ALP), thymidine kinase, alcohol
dehydrogenase, and RNA and DNA polymerases.
 Biochemical functions of zinc-containing metalloenzymes
includes protein synthesis, gene expression,
transport
processes, immunologic reactions, and wound
healing.
 Patients
on TPN
may
develop
acute
zinc deficiency.
 Zinc transport in serum uses albumin primarily and a2macroglobulin.
 Trace Minerals / Trace Elements to Monitor
2. Zinc Cont. ….
 Zinc is required for vision, taste, and smell functions. It
promotes tissue repair, connective tissue synthesis, bone
growth, and insulin synthesis.
 Malnutrition, infertility, inflammation, and hair loss are
often treated with zinc supplementation.
 Methods for zinc analysis include atomic absorption
spectroscopy, inductively coupled atomic plasma (ICP)
emission spectroscopy, and HPLC.
 Red cells contain zinc, so hemolysis elevates zinc plasma values.
 Trace Minerals / Trace Elements to Monitor
3. Iron
 Enzymes
requiring
iron
cofactor include
aconitase,
succinate dehydrogenase, and isocitrate dehydrogenase from
the TCA cycle.
 Catalase and myeloperoxidase found in neutrophils both require
iron as cofactor.
 Ribonucleotide reductase and xanthine oxidase involved in RNA
and DNA metabolism.
 Deficiencies of iron are associated with anemia.
 Excess iron has been associated with increasing the amount of
free radicals and infection in patients.
 Trace Minerals / Trace Elements to Monitor
4. Selenium
 Have an influence on
diabetes, and arthritis.
cancer,
cardiovascular
diseases,
 Essential cofactor to the antioxidant enzyme glutathione
peroxidase, which is involved in neutralizing hydrogen
peroxide formed during lipid oxidation in cells.
 Functions of selenium in humans include anti-atherogenic
effect, anticancer effect, antioxidant, improved fetility, and
increasing the immune response.
 Excessive selenium can occur with excessive supplementation.
Effects include fatigue, irritability, loss of hair and nails,
vomiting, nerve damage, and skin rashes.
 Trace Minerals / Trace Elements to Monitor
4. Selenium Cont. …..
 The cardiomyopathy effects of selenium deficiency are seen in
home parenteral nutrition or HPN.
 Methods for determining selenium have been flameless
atomic absorption spectroscopy or spectrofluorometry.
 Elevated
values
need to be confirmed with a second
specimen collection and analysis.