Food And Nutrition Basics Module 1 PDF

Food and Nutrition Basics Module 1/ Nutrition, Metabolism and Digestion  Module 1/ Nutrition, Metabolism and Digestion Section 1 Section 1 Objectives When you f...

Food and Nutrition Basics Module 1/ Nutrition, Metabolism and Digestion  Module 1/ Nutrition, Metabolism and Digestion Section 1 Section 1 Objectives When you finish this section, you should be Nutrition and nutrient able to state the definitions of the following terms: Metabolism, catabolism and anabolism Energy Kilocalorie and kiloJoule 2 /3 Additional Information Notes: Cells renewal process – The rate and speed at which the body cells are renewed varies a lot depending on the type of tissue. For example, red blood cells are renewed every 4 months, certain cells of the digestive tract are replaced by new ones every 1 - 2 days. Generally speaking, on an aver- age, every 3 months all body cells are renewed, with the exception of the cells which make up the nervous tissues; nerve cells are not renewed, and once formed remain throughout the entire life.  Module 1 / Nutrition, Metabolism and Digestion Section 1 Nutrition All these implications relate to the fact that Refers to how the body uses the nutritive the body’s tissues are made up of millions of substances contained in food, so that the body individual cells, which require nutrients to can carry out its functions properly. In other carry out the chemical reactions which keep words, nutrition is the science of food in its them alive and functioning properly. relationship to health but health is more than the absence of disease. In fact, the cells have a considerable shorter life span than the body itself and must there- fore constantly be replaced by new ones. For this renewal process, the body requires the nutrients contained in the food, so in a sense, these nutrients become part of the cells structure. This is what is meant by “You are what you Nutrition eat”. the science of food in its relationship to health but health is more than the absence of disease Nutrients The nutritive substances contained in the food which the body needs to function properly are known as nutrients. If one or more essential nutrients are constantly missing from the diet, «You are what you eat» serious illness or even death may result. For instance, without the proper nutrients in the right amounts, one can become blind, sterile, or mentally retarded. Bones can break, teeth and hair can fall out, and skin may flake away. 4 /5 Additional Information Average daily energy requirements (according to the WHO, FAO/UNU* in kcal/day) Sex: Weight Activity Sitting Standing Heavy Athletes Work Female 20 to 40 45 kg 1650 1750 1850 2100 years of age 55 kg 1850 2000 2100 2400 65 kg 2050 2150 2300 2600 75 kg 2250 2400 2550 2900 Sex: Weight Activity Sitting Standing Heavy Athletes Work Male 20 to 40 55 kg 2100 2400 2700 3300 years of age 65 kg 2350 2700 3000 3700 75 kg 2500 2900 3300 4000 85 kg 2700 3000 3400 4200 * WHO: The World Health Organisation FAO : United Nation Food and Agriculture Organisation UNU: United Nations University Activity – The table below shows for a 70 kg man the average costs in kcal/hour for various specific activities: Activity kcal/hour Rest or sleep 80 Sitting 100 Driving (car) 120 Housework 180 Walking (4.0 km/h.; 2.5 mph) 210 Golf 250 Walking (5.5 km/h.; 3.5 mph) 300 Table Tennis 360 Weed Chopping 400 Tennis 420 Soccer / Football 600 Running (16 km/h.; 10 mph) 900  Module 1 / Nutrition, Metabolism and Digestion Section 1 Metabolism A kilocalorie is defined as the amount of energy (heat) necessary to raise the tempera- The individual cells and the chemical reac- ture of 1 kg, or one litre of water by 1° (° Celsius tions occurring in them enables the body as a or Centigrade) from 14.5°C to 15.5°C. whole to function as an integrated system. The general term used for all the chemical 15.5°C reactions in the body is metabolism. There are two basic types of metabolism which occur – anabolism and catabolism. During anabolism 1kg or substances are assembled. During catabolism 1 litre substances are broken down. of water Two Basic Types of Metabolism 14.5°C Anabolism One kilocalorie (kcal) is approximately equal substances are to four kiloJoules (kJ). assembled More precisely 1 kcal = 4.18 kJ Catabolism substances are 1 kcal = 4.18 kJ broken down Energy requirements Energy The average daily energy requirements of a sedentary individual are approximately 2000 Energy is the ability to do work. In the con- kcal per day; while a highly active person may text of human nutrition, it refers to the body’s require an average of 3500 kcal per day. capacity to use the energy contained in the To arrive to more precise figures, factors such nutrients by breaking down, or catabolising, as age, weight, sex and the degree of activity them. must be taken into account. The energy content of food is usually expressed in terms of kilocalories (or kilo- Joules) just as distance can be expressed in kilometers (or miles) and weight in kilograms (or pounds). 6 /7 Notes:  Module 1 / Nutrition, Metabolism and Digestion Section 1 Progress Check Match each of the following terms with its definition or description. Terms: Definition or Description: A nutrient 1 The ability to do work (derived from the breaking down of nutrients in the cells of the B nutrition body) C metabolism 2 A unit of measure of the energy content of food (equal to the amount of heat necessary to D catabolism raise the temperature of one kilogram of water from 14.5°C to 15.5°C) E anabolism 3 The science of food in its relationship to F energy health but health is more than the absence of disease G kilocalorie 4 The sum total of all of the chemical reactions H kiloJoule during which substances are broken down 5 Nutritive substances contained in the food and required by the body to function properly 6 The sum total of all the chemical reactions during which substances are assembled 7 A unit of measure of the energy content of food (4.18 of these units equal one kilocalorie) 8 The sum total of all the chemical reactions that take place in the body Answers on the following page 8 /9 Progress Check Answers Terms: A nutrient 5 B nutrition 3 C metabolism 8 D catabolism 4 E anabolism 6 F energy 1 G kilocalorie 2 H kiloJoule 7 If you have correctly answered all these questions, proceed to the Objectives for Section 2; otherwise please carefully read this Section again. 10  Module 1/Nutrition, Metabolism and Digestion Section 2 Section 2 Objectives Upon completion of this section you should be Name the nutrients contained in food. able to : Name the functions of the different nutrients. State the definition of - micronutrients - macronutrients - essential nutrients Specify the number of kilocalories and kiloJoules provided by each of the energy nutrients. 11 Additional Information Notes: Macronutrients and micronutrients – The diagram below shows the average diet composition as dry matter: Diet Composition (% dry matter) Carbohydrate 62% Fat 19% Protein 18% Minerals / Trace elements