Lecture 01.pdf

Fundamentals of Human Nutrition FQM 1172 Dr. Thilanka Ranathunga Dept. of Applied Nutrition 1  Aims To provide students with understanding of general principles of nutrition with particular emphasis on; - diffe...

Fundamentals of Human Nutrition FQM 1172 Dr. Thilanka Ranathunga Dept. of Applied Nutrition 1  Aims To provide students with understanding of general principles of nutrition with particular emphasis on; - different nutrients - functions of foods - nutrient standards - Provide the understanding about the human energy systems (energy intake and expenditure) - Identify the calculation of energy requirement - Explain how energy balance occurs in the body 2  Learning objectives Define “nutrition” and list and categorize the nutrients Explain total energy requirements of a human Explain how energy expenditure occurs Explain dietary energy intake and energy balance 3  What are nutrients? 1. Nutrients are compounds in foods essential for healthy life. It provides us, - energy - the building blocks for repair and growth - substances necessary to regulate chemical processes 2. Nutrients are substances used by living organism to survive, grow, and reproduce 4  List of nutrients and its classification There are six major nutrients Carbohydrates (CHO) Lipids (fats) Macro nutrients Proteins Vitamins Micro nutrients Minerals Water Dietary fibers Non Bioactive compounds nutrients 5  Broad categories of nutrients Macro nutrients: Macronutrients are nutrients that a person needs in larger amounts. Macronutrients include water, protein, carbohydrates, and fats. Micro nutrients : Micronutrients are nutrients that a person needs in small amounts. Micronutrients consist of vitamins and minerals. Although the body only needs small amounts of them, a deficiency can cause ill health. Essential for the body metabolism 6  Broad categories of nutrients Classification 1 cont… Essential nutrients : Need to provide to the body through diet Non-essential nutrients : Body can synthase Classification 2 Energy giving – Provide calories for body functions (CHO & Fats) Body building – Provide building blocks (amino acids) to build body (Proteins) Protecting the body – From micro organism (Vitamins and Minerals) 7 Functions of foods 8  Nutrient intake standards Called as “Nutrient intake values/dietary standards” The amounts of nutrient intakes recommended vary from country to country Common standards are used to set the recommended nutrient intake for a population Other factors : - Age - Gender - Physiological stage - Current nutritional status - Diseases condition 9 Nutrient intake standards EAR values are most important because they are used to calculate the Recommended Daily Allowance (RDA) values, which are commonly used as population-wide recommendations for nutrient intake. Developed for different age groups, sex and life stages 10 Nutrient intake standards RDA = EAR + 2 SD EAR 11 Nutrient intake standards 12 Energy intake, expenditure and energy balance 13  Human Energy system Human energy is the power that is produced by human body to do various activities The form of energy in the body : Adenosine Triphosphate (ATP) ATP are composed of; - Adenine group - Ribose sugar group - Phosphate group 14  Way we need energy? To do activities To repair cells/tissues For growth 15  Units of energy measures Joule, Calorie, Kilocalorie J, KJ, MJ cal, kcal 1000 cal = kcal 1 cal = 4.184 joules Calorie : the amount of heat needed to increase the temperature of 1 g of water from 14.5 to 15.5 0C 16 Sources of energy for human body Food and beverages Foods provide more energy than beverages Constituents of foods that provide energy: 1. ………………………… 2. ……………………….. 3. ………………………… 4. ………………………….. Those are macronutrients (except ………) 17  Atwater factor Amount of energy provided by 1g of macronutrients is called “Atwater factor”. CHO : 4 kcal/g Protein : 4 kcal/g Fats : 9 kcal/g Alcohol : 7 kcal/g 18  Energy expenditure Human expend energy for main 3 things 1. Resting metabolic rate (RMR) 2. Energy for physical activities (EE PA) 3. Thermic effect of foods (TEF) TEF : Thermal Effect of Foods – energy needed to absorb, digest and metabolize foods RMR (Resting Metabolic Rate) - energy required for the body when the person is at completely rest EE PA : Energy Expenditure for physical activity 19  Total Energy Expenditure BMR (Basal Metabolic Rate) TEE = TEF + PA + BMR Rate at which body uses energy when the body is at complete rest Energy need for activity of internal organs & body T 60-70% of Total Energy Expenditure (TEE) Physical activity Energy needed for mechanical work 25-30% of TEE PAL (Physical Activity Level ) = TEE/BMR Thermic Effect of Foods Energy to digest, absorb, metabolize foods 10% of TEE 20  Physical Activity Level PAL is a way to express a person's daily physical activity as a number, and is used to estimate a person's total energy expenditure PAL = TEE/BMR 21 PAR (Physical Activity Ratio) = Energy cost of an activity per minute/BMR per minutes 22  Calculating BMR Harris Benedict Equation 23 Calculating daily energy requirement Energy Requirement = BMR + Energy for physical activity Or Energy Requirement = BMR x PAL BMR Women 0.9 kcal/kg/hr Men 1 kcal/kg/hr Or Harris Benedict Equation 24 Energy Balance 25  Obesity Excess accumulation of body energy in the form of body fat in adipose tissues Increase health risk BMI = weight (kg) / height2(m) Obese > 30 kgm-2, Over weight 25-30 kgm -2 Normal 18.5 –24.9 kgm -2 Underweight