nutrients and assessment

1. NUTRIENTSand ASSESSMENT Myrna D.C. San Pedro, MD, FPPS

2. NUTRITION Combination of processes by which the living organism receives & uses the materials necessary for growth, maintenance of functions & repair of component parts

3. METABOLISM All the changes in the foodstuffs from absorption in the digestive tract until elimination by the excretory organs

4. Nutrient Requirement: the amount to replace obligatory losses & support synthesis of new tissues; varies by age, sex, size & growth rate Energy Requirement/Expenditure: Basal Metabolic Rate (BMR) Specific Dynamic Action of food (SDA) Body activity Growth allowance Losses per excreta

5. Basal Metabolic Rate (BMR) Energy expenditure of an awake individual at rest in a thermoneutral environment after an overnight or 14 hours fasting Most closely related to lean body mass Factors: metabolic disorders, surgery, infections, anorexia or fever; for example, basal metabolism increases by about 10% for each centigrade of fever 50-100% of resting metabolic rate in infants and 20-25% in adults goes to maintenance of temperature In infants about 55 kcal/kg/day which decreases to 25-30 kcal/kg/day at maturity

6. Specific Dynamic Action (SDA) The obligation to expend energy to digest & assimilate food Highest for proteins & lowest for carbohydrates About 5 kcal/kg/day

7. Body activity (exercise & physical activity): average allowance during the first year is 25 kcal/kg/day Growth allowance: during the first 4 months is about 15-20 kcal/kg/day which decreases to 12 kcal/kg/day at the end of the first year Fecal loss: 8 kcal/kg/day in the form of unused fats & proteins

8. Thus, the energy requirement of the infant or child is the level of intake which can

9. Daily Requirement Approximately 80-120 kcal/kg body weight for the 1st year of life with subsequent decreases of about 10 kcal/kg body weight for each succeeding 3-year period

10. Recommended Dietary Allowances(RDAs, USA) Other terms are Recommended Dietary Intakes (RDIs, UK) and Safe Levels of Intake (FAO/WHO) The levels of intake of essential nutrients that are judged by the Food and Nutrition Board, based on scientific knowledge, to be adequate to meet the known nutrient needs of practically all healthy persons An important element is that recommended intakes must be adequate for population groups implying that safety margins are inherent in these recommendations

11. MAJOR NUTRIENTS Carbohydrates Proteins Fats Vitamins Minerals Water

12. Energy is provided by the following Carbohydrates: 60% (45-65%) of the diet 1gm provides 4 kcal Proteins: 11% (9-15%) of the diet 1gm provides 4 kcal Fats: 35% (25-45%) of the diet 1gm short-chain provides 5.3 kcal 1gm medium-chain provides 8.3 kcal 1gm long-chain provides 9 kcal

13. Carbohydrates’ Functions Readily available source & supply most of the body’s energy needs Antiketogenic Structure of cells Store calories as glycogen Convert to fat Amino acid synthesis Cellulose as roughage

15. Proteins’ Functions Supply amino acids for growth & repair of body tissues Supply ions in acid-base balance Part of hemoglobin, nucleoproteins, glycoproteins & lipoproteins As enzymes, hormones, antibodies & cellular respiratory substance Protective structure (nails & hair) Source of energy when there is shortage of fats & carbohydrates

17. Daily Protein Requirement

18. Essential Amino Acids Essential nutrient: A substance necessary for normal metabolic functioning but cannot be synthesized by the body and must be obtained from the diet 24 amino acids identified 9 are found to be essential for children: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan & valine Arginine, cystine & taurine are essential for LBW infants

19. Evaluating Protein Quality Protein Efficiency Ratio (PER): Wt gained/gm protein consumed; the U.S. FDA used the PER as the basis for the % of the USRDA for protein on food labels but PER was based upon the a. a. requirements of growing rats, which are different from humans Biologic Value (BV) of protein: Amount of nitrogen accumulated compared with nitrogen absorbed; indicates effectiveness of utilization but does not take into account certain factors influencing digestion Net Protein Utilization (NPU): Percentage of nitrogen consumed that is retained by the body; influenced by factors other than inherent a. a. composition such as reduced digestibility caused by overheating lowering protein value by decreasing availability of several essential a. a.

20. Evaluating Protein Quality Amino Acid Score (AAS): A chemical technique measuring indispensable a. a. in a protein and comparing values with a reference protein; considered fast, consistent, and inexpensive Protein Digestibility Corrected Amino Acid Score (PDCAAS ): Amino Acid Score w/added digestibility component; current accepted measure based on the amino acid requirements of humans; limitations: takes no account of where the proteins have been digested and may also be considered incomplete since human diets almost never contain only one kind of protein

21. Fats’ Functions A concentrated & reserve source of energy Physical protection for vessels, nerves, organs Insulate against changes in temperature Structure of body tissues, cell membranes & nuclei Carry the fat-soluble vitamins (A, D, E, K) Give appetite appeal Aid satiety (delay emptying time of the stomach) Spare protein Supply linoleic acid, the essential fatty acid

23. Essential Fatty Acids (EFAs) Linoleic acid (LA) & linolenic or alpha-linolenic acid (LNA or ALA) are the 2 EFAs; LA can be converted to both arachidonic and linolenic acids Necessary for growth, skin & hair integrity, regulation of cholesterol metabolism, lipotropic activity, decreased platelet adhesiveness and reproduction; diets w/<1-2% cal will affect growth rate, cause dry scaly rash w/ intertrigo and poor wound healing LA is abundant in soy oil, sunflower, safflower & sesame seeds, corn oil, and most nuts while LNA is found abundantly in flax, small quantities in walnuts, cold pressed canola oil, wheat germ and dark green leafy vegetables The right ratio of LA to ALA in the diet, about 3:1 or 2:1, is important; an imbalance may lead to a variety of mental disorders, including hyperactivity, depression, brain allergies, and schizophrenia

24. Omega-3 and Omega-6 Fats Polyunsaturated fatty acids (PUFA) containing more than one cis double bond ALA (18:3n-3) belongs to the omega-3 family of fatty acids while LA (18:2n-6) belongs to the omega-6 family; from these 2 EFAs can be manufactured other (non-essential) omega-3 and omega-6 fatty acids Important structural components of cell membranes, that, when incorporated into phospholipids, affect cell membrane properties such as fluidity, flexibility, permeability and the activity of membrane bound enzymes Lowers LDL cholesterol & decreases CV disease risk Can modulate the expression of a number of genes, including those involved with fatty acid metabolism and inflammation

25. Eicosanoids derived from DGLA, AA and EPA play critical roles in immune and inflammatory responses by being formed into prostaglandins and leukotrienes although EPA eicosanoids are less potent inducers of inflammation, blood vessel constriction, and coagulation than those derived from AA

26. DHA and AA are high in the phospholipids of brain gray matter suggesting their importance to CNS function such that depletion of DHA in the brain can result in learning deficits Also, EPA and DHA supplementation during pregnancy has beneficial effects on long-term cognitive development in children DHA appears to be important for visual and neurological development but it is not yet clear whether feeding infants formula enriched with DHA and AA enhances visual acuity or neurological development in preterm or term infants There is evidence, though, that human conversion of EPA and, particularly DHA, is relatively inefficient suggesting that EPA and DHA may also be essential under some conditions

27. Vitamins Organic compounds in minute amounts that catalyze cellular metabolism 16 vitamins, 8 of which are considered necessary for human nutrition: retinal, thiamin, riboflavin, niacin, cobalamin, folacin, ascorbic acid & vitamin D There is presumptive evidence that pyridoxine & tocopherol may be necessary for infant nutrition

28. Minerals Macrominerals Sodium 1gm or 2mEq/kg Potassium 1-2gm or 1.5mEq/kg Calcium 0.6gm/day Magnesium 150-300mg/day Chlorine 0.5gm/day Phosphorus Sulfur 0.5-1gm/day Microminerals Iron 1mg/kg/day Iodine 34-45 mcg/day Copper 0.5-1mg/kg/day Fluorine 0.5-1mg/day Zinc 3-5mg/kg/day Cobalt 1-2mcg/day Manganese 0.05-1.5mg/day Chromium 0.02-0.10mg/day Selenium 0.02-0.10mg/day Molybdenum 0.05-0.15mg/day

29. Macrominerals Sodium, Chloride, Potassium work together to regulate the flow of fluids in the body & help regulate the nervous system, muscle functions & nutrient absorption in the cells Calcium is needed for bone rigidity & helps in blood clotting, muscle contraction & normal nerve functions. Phosphorous aids in all phases of calcium metabolism & helps build strong bones & teeth Magnesium helps regulate body temperature, muscle contractions & the nervous system & helps cells utilize carbohydrates, fats, and proteins Sulfur helps in detoxification reactions & is present in the amino acids in proteins & a component of constituents of mucopolysaccharides & essential compounds

30. Microminerals Iron combines with protein to form hemoglobin Iodine is needed by thyroid gland to produce thyroxine Copper is necessary in the formation of hemoglobin Fluorine helps reduce incidence of tooth decay Zinc plays an important role in the formation of protein, thus, assists in wound healing, blood formation and general growth & maintenance of all tissues Cobalt is a component of vitamin B12 Manganese is necessary for normal development of bones and connective tissues Chromium maintains normal glucose uptake into cells & helps insulin bind to cells Selenium w/vitamin E protects cells from destruction Molybdenum is a component of xanthine oxidase and aldehyde oxidase

31. Water Essential for life Two-thirds of body weight, 75-80% in infants while 55-60% in adults Daily consumption by a healthy infant is 10-15% BW versus 2-4% BW in adult Of fluid intake: water retention 0.5-3%, evaporation from lungs & skin 40-50%, fecal losses 3-10% & renal excretion about 40-50% or more Fruits & vegetables 90% water

32. ASSESSMENT OF NUTRITIONAL STATUS OF CHILDREN History Dietary history of mother & child History of height & weight changes Anthropometric indicators Evidence of deviations from average height & weight Evidence of depletion of fat depots Evidence of decrease in muscle mass Change in psychic reaction Reaction to infection Evidence of specific deficiencies

33. ANTHROPOMETRIC INDICATORS OF NUTRITIONAL STATUS Weight: index of acute nutritional status Height or length: unaffected by excess fat or fluid; assesses growth failure Weight for height measurement: more accurately assesses body build Measure child’s height Find age for which measured height is on the 50th % on the growth curve Child’s actual weight (numerator) 50th% wt based on age of plotted ht (denominator)

34. Head circumference: influenced by nutrition till age 36 mo; measurements < 5th% may indicates chronic undernutrition during fetal life & early childhood Skinfold thickness(TSF): provides an estimation of total body fat Mid-arm circumference (MAC)/Mid-arm muscle circumference (MAMC): with TSF, determines muscle area & fat area **MAMC = MAC – (3.4 x TSF) Bone age: epiphyseal closure; percentage of maturity attained indicates potential for catch-up growth

35. Growth Velocity (GV) Evaluates change in rate of growth over a specific time period expressed in cm/yr; more sensitive way of assessing growth failure or slowed growth Formula: GV (cm) = H2 (cm) – H1 (cm) T (yr) where H1 = initial height in centimeters H2 = height at next measurement T = period between two measurements in years

36. Body Mass Index (BMI)-for-Age An effective screening tool specific for age and gender but not a diagnostic tool Formula: Weight (kg)/[Height (m)]2 Calculation: [weight (kg)/ height (cm)/height (cm)] x 10,000 BMI-for-age cut-offs: > 95th % Overweight 85th - < 95th % Risk of overweight < 5th % Underweight BMI-for-age correlates w/ clinical risk factors in CVS disease such as hyperlipidemia, elevated insulin & high blood pressure during middle age

37. Can you see risk?

38. BMI-for-Age During early childhood, BMI decreases reaching a nadir (the so-called rebound point) between 4 and 7 years of age, then increases to 20 years of age reflecting the normal changes in body composition during puberty.