Nutritional Requirements and Assessment

NUTRITIONAL REQUIREMENTS @ NUTRITIONAL ASSESMENT 10/07/2024 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...

NUTRITIONAL REQUIREMENTS @ NUTRITIONAL ASSESMENT 10/07/2024 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 10/07/2024 2  We eat food because our body need: energy; compounds for growth, repair and reproduction; substances to regulate the production of energy, growth and repair. 10/07/2024 3 The energy supply Foods containing… protein carbohydrate fat …provide the body with energy. 10/07/2024 4 The other functions Food also provides… fibre; water; vitamins and minerals. These substances do not provide the body with energy, but are all needed to fulfil some important ‘support’ functions for the body. 10/07/2024 5  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 10/07/2024 6 Energy and nutrients Food and drinks provide us with different amounts of energy because of the variety of nutrients they contain. 1g protein provides (4 kcal). 1g carbohydrate provides 4kcal). 1g fat provides (9 kcal). 10/07/2024 7 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. 10/07/2024 8  Energy contribution These foods provide 400kJ of energy: 10/07/2024 9  Energy in vs Energy out Number of minutes to use up 400kJ of energy: 10/07/2024 10 What Is a Healthy Diet? – Fulfills energy needs (macronutrients) – Provides sufficient amounts of essential nutrients (micronutrients) – Reduces risk of disease – Is safe to consume (low contaminants or potentially harmful 10/07/2024 added substances) 11  Energy requirement 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 10/07/2024 12  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 10/07/2024 13  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. 10/07/2024 14  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. 10/07/2024 15  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 10/07/2024 16  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 10/07/2024 17  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. 10/07/2024 18 NUTRITIONAL REQUIREMENT 10/07/2024 19  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. 10/07/2024 20  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) 10/07/2024 21  Estimated average requirement (EAR) : This is an estimate of the average requirement for 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 10/07/2024 22  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. 10/07/2024 23  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 10/07/2024 24  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. 10/07/2024 25  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 10/07/2024 26 EARs, RDA/AIs and ULs for an average healthy adult males aged 30-50 years old are shown below Nutrient EAR RDA/AI UL Unit Vitamin A 625 900 3000 µg Vitamin C 75 90 2000 mg Vitamin D 10 15 100 µg Vitamin B6 1.1 1.3 100 mg α-tocopherol(Vitamin E) 12 15 1000 mg Calcium 800 1000 2500 mg Copper 700 900 10000 µg Folate (B9) 320 400 1000 µg Iodine 95 150 1100 µg Iron 6 8 45 mg Phosphorus 580 700 4000 mg Thiamin (B1) 1.0 1.2 ND mg Zinc 9.4 11 40 mg 10/07/2024 27  DRI 10/07/2024 28 Scientific Basis for Establishing DRIs  Observed intakes in healthy populations  Epidemiological observations (Researches)  Animal experiments  Biochemical measurements 10/07/2024 29  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 For men EER = 662 – (9.53 X AGE) + PA X (15.91 X WT + 539.6 X HT) For Women EER = 354 – (6.91 X AGE) + PA X (9.36 X WT + 726 X HT) 10/07/2024 30  Physical activity (PA) For men women Sedantary 1 1 Low active 1.12 1.14 Active 1.27 1.27 Very active 1.54 1.45 10/07/2024 31  Nutritional Requirement during Critical Periods 10/07/2024 32  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 10/07/2024 33  Pregnancy Pregnancy is considered physiological if mothers: Produce a healthy baby with appropriate weight at birth Produce enough milk ( >750g/day in the first 6 months) and of good quality for the growth of exclusively breast fed infants during the first 6 months Mothers’ nutritional status is not 10/07/2024 34  Prenatal nutrition is affected by: --Nutritional status prior to pregnancy and during pregnancy - Maternal age- adolescents need more calories - Parity 10/07/2024 35  Pregnancy Increased requirements for energy & nutrients for Formation of tissue- placenta, fetus, amniotic fluid Increase in tissue -uterus, blood volume, breast & fat deposition Other changes- increased BMR So Adequate nutrition before & during pregnancy is essential for its progress & outcome. 10/07/2024 36  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 Abortions, stillbirths & fetal malformations, morbidity & mortality (perinatal, infant & maternal), impaired growth & psycho-motor developments 10/07/2024 37  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 10/07/2024 38 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 10/07/2024 39  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 10/07/2024 status 40  Recommended weight gains based on pre- pregnancy weight _______________________________________________________ Pre pregnancy weight Recommended weight gain (kg) First trimester Total wt gain _______________________________________________________ Underweight (BMI