Nutritional Requirements & Assessment PDF

1  Learning objectives At the end of this session you are expected to Describe factors affecting nutrient and energy requrement Explain nutritional need at different life stages Discuss different methods of nutritional assessment...

1  Learning objectives At the end of this session you are expected to Describe factors affecting nutrient and energy requrement Explain nutritional need at different life stages Discuss different methods of nutritional assessment 2  How is energy measured? Food Energy is measured in units known as kilojoules (kJ) and kilocalories (kcal). This is a different way of measuring energy, just as distance is measured in centimetres and inches. 1 kilocalorie =4.18400 kilojoules hiwot Energy balance Different people need different amounts of energy. Some activities use more energy than others. It is important to balance the amount of energy we eat with the amount of energy we use up. hiwot  Energy requirement Energy requirement is the amount needed to maintain health, growth, and an “appropriate” level of physical activity. 5  Principles and Definitions Human energy requirements are estimated from measures of – energy expenditure plus the additional energy needed for (growth, pregnancy and lactation. Energy balance is achieved when – input (i.e. dietary energy intake) is equal to output (i.e. total energy expenditure), – plus the energy cost of growth in childhood and pregnancy, or the energy cost to produce milk during lactation 6  Components of Energy Requirements Human beings need energy for the following: 1. Basal metabolism: comprises functions that are essential for life, such as – Cell function and replacement – The synthesis and secretion of enzymes and hormones. – Transportation of proteins and other substances – The maintenance of body temperature; – Uninterrupted work of cardiac , respiratory muscles and brain function BM represents 45 to 70 % of daily total energy. 7 Components of Energy Requirements... 2.Metabolic response to food: Eating requires energy for – ingestion , digestion of food, – and for the absorption, transport, etc of nutrients. 8  Components of Energy Requirements… 3.Physical activity. This is the most variable and second largest component of daily energy expenditure next to BMR 4. Growth. The energy cost of growth has two components: – 1) the energy needed to synthesize growing tissues; and – 2) the energy deposited in those tissues. 9  Components of Energy Requirements... 5.Pregnancy. During pregnancy, extra energy is needed for – the growth of the foetus, placenta and various maternal tissues 6.Lactation. The energy cost of lactation has two components: 1) the energy required to produce that milk ; and 2) the energy content of the milk secreted 10  Changes in energy requirements with age BMR, depends on the mass of metabolically active(muscle) tissue in the body, The changes in body composition with age, – markedly affect energy requirements BMR is higher during child hood and adolescent and becomes lower during old age 11  Sex differences in energy requirements Men have a relatively greater muscle mass than women The greater body fat content of women means that – BMR per unit total body weight is somewhat lower in women. 12  Nutritional Requirement “ is defined as the The amount of each nutrient needed These are different for each nutrient and also vary between individuals and life stages, – e.g. women of childbearing age need more iron than men. 13  Dietary Reference Intakes (DRI) DRI’s are quantitative estimates of nutrient intake to be used for planning and assessing diets of healthy people Include: Estimated Average Requirement (EAR) Recommended Dietary Allowance (RDA) Lower Reference Nutrient Intake ( LRNI) Adequate Intake (AI) Tolerable Upper Intake Level (UL) 14  Estimated average requirement (EAR) This is an estimate of the : requirement for average energy or a nutrient It satisfies the energy and nutrient need of 50% of the population approximately 50% of a group of people will require more or less 15  Recommended dietary allowance(RDA) Is the daily intake, which meets the requirements of – almost all (97.5 percent) apparently healthy individuals in age and sex-specific population group. RDA s are used mainly for – protein, vitamins and minerals. 16  Lower Reference Nutrient Intake (LRNI) The amount of a nutrient that is enough – for only the small number of people (2.5%) The majority of the population need more 17  Adequate intake (safe intake): These values are based on – Observationally determined estimates of nutrient intake by a group (s) of healthy individuals. At this level there is no risk of deficiency and is below the level where it causes toxicity. 18  Upper tolerable nutrient intake level Are the maximum intake from food that is unlikely to pose risk of adverse health effects in almost all (97.5 %) apparently healthy individuals in an age and sex- specific population group 19 DRI Scientific Basis for Establishing DRIs § Observed intakes in healthy populations § Epidemiological observations (Researches) § Animal experiments § Biochemical measurements 21  Diet planning for an adult in a group Criteria for selecting food items – Meeting the calorie requirement – AMDR(Acceptable macronutrient distribution range) – Dietary diversity (at least 3 types) – Availability in the market – Health condition – physiological status – Likes/dislikes – Affordability 22  Determining energy need Estimated Energy Requirement (EER) –Average dietary energy intake (kcal) to maintain energy balance –Based on age, sex, weight, height, level of physical activity Determining Nutrient Needs for macro nutrients Acceptable Macronutrient Distribution Ranges (AMDR) – Describes the portion of the energy intake that should come from each macronutrient – Expressed as ranges (percentage of total energy) with upper and lower boundary. Recommended AMDR – Carbohydrate=45%-65% – Fat=20-35% – Protein =8-10% Nutritional Requirement during Critical Periods 25  There is Special nutrient requirement during: – Pregnancy – Lactation – Infancy, adolescence … – Old age These groups are Vulnerable to malnutrition b/c – inadequacy plus – special requirement And it is an intergenerational 26  Pregnancy Pregnancy is considered physiological if mothers: üProduce a healthy baby with appropriate weight at birth üProduce enough milk ( >750g/day in the first 6 months) and üof good quality for the growth of exclusively breast fed infants during the first 6 months üMothers’ nutritional status is not depleted 27  Prenatal nutrition is affected by: --Nutritional status prior to pregnancy and during pregnancy - Maternal age- adolescents need more calories - Parity 28  Pregnancy Increased requirements for energy & nutrients for üFormation of tissue- üplacenta, fetus, amniotic fluid üIncrease in tissue ü-uterus, blood volume, breast & fat deposition üOther changes- increased BMR So Adequate nutrition before & during pregnancy is essential for its progress & outcome. 29  There is strong evidence for r/ship b/n pre-pregnancy weight & weight gain during pregnancy and mortality during pregnancy. -ve outcomes of pregnancy- are more common in poorly nourished women üAbortions, stillbirths & fetal malformations, morbidity & mortality (perinatal, infant & maternal), impaired growth & psycho-motor developments 30  Pregnancy Weight gain is essential to the well being of the developing fetus First 2 trimesters – Anabolic ( growth of breasts, uterus/placenta production of amniotic fluid, increased in blood volume & deposition of body fat). – The fetal growth is slow 31 Later trimester – Fetal growth- tripling of weight b/n 28 & 40 wks (1000g to 3200-3600g) – Catabolic for mother- uses fat stores – If her intake is not sufficient -she will loose weight – the most vulnerable period for the fetus in terms of birth weight 32  Pregnancy A well nourished woman before pregnancy is expected to gains – ~20% (11-16kg) of her pre-pregnant weight during pregnancy 1st trimester- 1 to 2 kg & then 0.5 kg/wk – 60% attributable to maternal weight gain- fluid volume, protein & fat deposition – 40%-attributable to fetus, placenta, & amniotic fluid,fetus The required weight gain depends on pre-pregnancy status Recommended weight gains based on pre-pregnancy weight _______________________________________________________ Pre pregnancy weight Recommended weight gain (kg) First trimester Total wt gain _______________________________________________________ Underweight (BMI