Unit 2 Nutrients in food Nutrients in food Functions of food Different types of food Carbohydrates Natural food Proteins Fats and oils Vitamins and minerals Processed food Why is food processed? Food labels 43
All living things need food to survive. Your stomach will quickly remind you when you have not eaten for a while. In this unit we will learn more about the different functions of food in our bodies. We will look at the variety of food that is available and why it is important to eat from all food types. After all, it is best to live healthily and feel good, is it not? 2.1 Functions of food The foods that we eat play an important role in our bodies. It has the following functions: It provides energy. 44 It helps us grow and recover.
It helps with insulation and it protects our organs and nerves. It builds healthy bones and teeth. It builds a healthy immune system. Your body needs energy to function. You use energy to grow, play sports, do school work, etc. The food you eat provides the energy that you need to live. Your body needs food to grow and build muscle. When you are injured, the nutrients in food help your body recover. In the previous unit, you learned that plants store starch as a source of energy. After you have eaten, the blood in your body transports energy to your body parts. Energy is stored in your blood, muscles and fat. I m having a dinner party! And the two of you are my special guests tonight. Bertha, I don t think we can trust this guy. 45
A layer of fat under your skin protects your body against cold. The food you eat supplies your body with the nutrients to build up this layer of fat. Food also helps us to build layers of fat around our organs. This fatty layer is necessary for protection of the organs. Imagine you had no teeth in your mouth. It would be very difficult to eat food and it would also not look good. On top of that, you would struggle to talk. Have you ever thought of the important role that your skeleton plays? Without it, you would not be able to stand, sit or move around. Food plays an important role in keeping your skeleton (bones) and teeth healthy and strong. Your immune system keeps you healthy and protects you against germs. Hhis musss be a nychemare! The protection given by the fatty layer is called insulation. Quick, Bertha! Bury these teeth! When your immune system is weak, you get sick easily and often. You also struggle to get better again. Therefore, you must eat food that ensures a healthy immune system. 46
2.2 Different types of food We can divide food into different groups. One way is to group food according to the function thereof in the human body. The function of food in the human body determines the group into which it is divided. According to this, the four groups are carbohydrates, proteins, fats and oils as well as vitamins and minerals. 2.2.1 Carbohydrates Carbohydrates are also called starch. Remember, this is what is stored in plants after photosynthesis. Examples of foods that contain carbohydrates: bread pasta cereal porridge potato sweet potato 47
What is the function of carbohydrates in your body? They provide energy. What happens to carbohydrates in your body? Carbohydrates are broken down to glucose (a simple sugar). The glucose is absorbed by your blood stream. Energy is supplied to your entire body through your blood stream. Carbohydrates broken down to glucose through blood stream energy to your entire body 2.2.2 Proteins Examples of foods that contain protein: red meat white meat eggs 48
lentils nuts cheese What is the function of proteins in your body? Proteins help you grow by building tissue. It also helps your body recover/heal. Your muscles, organs and immune system are maintained by proteins. If your muscles, organs or immune system have been damaged, proteins help them to recover/heal. You a re specially invited to a protein-rich dinner! B e rt h a... What happens to proteins in your body? Your body breaks down proteins into small particles that are called amino acids. Amino acids are used to build up your muscles, bones, blood and organs, and to keep them strong. They also help with recovery/ healing. ans g r o, s uscle t) and m r u o Y r hear stem u o y. (e.g e sy n u m m your i t mainly of consis teins. pro not o d.... I s t i l l s t t h is tru 49
2.2.3 Fats and oils Examples of foods that contain fats and oils: avocado butter margarine olive oil peanut butter ice cream Most people think that a healthy diet does not contain fats. However, it is important that fats form part of your diet. What is the function of fats in your body? Fats store energy in the form of body fat. 50
Fats help your body to absorb certain vitamins. Some organs, like your kidneys and liver, are protected by a layer of fat. A fat layer under your skin insulates you against cold and keeps you warm. Be careful! Do not eat or drink an excess of fats. It is not good for your health. 2.2.4 Vitamins and minerals Examples of foods that contain vitamins and minerals: lers d d o nd t ed to a s e i Bab ly ne y help l a i c espe fats. The d an in take ir brains s to the s sytem u l. nervo elop wel dev spinach peas oranges milk 51
More examples of foods that contain vitamins and minerals: broccoli bananas yoghurt lettuce melon tomatoes What is the function of vitamins and minerals in your body? They keep you healthy and build a good immune system. They help to build healthy and strong bones and teeth. There is a large variety of vitamins and minerals. Each has a specific purpose in your body. The following table gives more information: 52
Vitamin A Vitamin B Vitamin/ mineral Examples of food that contains it Spinach Carrots Peas Broccoli Function in your body Keeps your eyes and eyesight healthy. Protects against infection. Releases energy. Makes red blood cells. Vitamin C Citrus fruit, like oranges and naartjies Keeps your immune system healthy. Protects against infection. Heals wounds. Vitamin E Broccoli Lettuce Protects your cells and tissue. Keeps your red blood cells healthy. Calcium Iron Potassium Milk Yoghurt Green vegetables, e.g. spinach, peas and beans Bananas Tomatoes Builds strong bones. Builds teeth and keeps them healthy. Transports oxygen in your body. Helps with the functioning of your muscles and nervous system. 53