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Cookery and Nutrition Beginners Carbohydrates This is a group of foods which contains starch, NSP (dietary fibre) and sugar. Carbohydrates are usually plant products. Carbohydrates STARCH We should eat plenty of starchy cereal foods. Such as: rice oats, barley, maize and rye and starchy vegetables like potatoes and squash. 1. SUGAR NSP Starchy foods like wheat, rice and other cereals are usually ‘wrapped in fibrous cell walls made up of NSP (bran). WE should not get more than 10% of our daily energy from sugars. These are called empty foods, because they just provide us with energy and nothing else. (There is not nutritional advantage of using brown sugar.) Functions of Carbohydrates in the diet Supply the body with 45% of the energy. Contribute to the cell structure Keeps us warm If carbohydrates are taken for energy, proteins can do their primary functions of body building rather than energy. This process is called Protein sparer. 2. Characteristics Daily energy intake from Carbohydrates should be 45% whilst that of sugar less than 10%. 1 gram of carbohydrates is 4 Kilo Calorie. Found mainly in plant origin foods. Are the cheapest to buy. Vitamin B helps the breakdown of Carbohydrates. Made up from a carbon, hydrogen and oxygen. Sugars 1. Classification of sugars: Monosaccharide: composed of 1 sugar unit. Called simple sugars. Fructose: mainly found in fruits (and honey). Glucose: found in ripe fruit and some vegetables. Galactose: found in milk of mammals. Disaccharides Two monosaccharide joined together. Sucrose: 1 glucose + 1 fructose. Used in cookery(cane sugar) Ms. J. Borg -1- Cookery and Nutrition Beginners Lactose: 1 glucose + 1 galactose. Found in milk of mammals. Maltose: 1 glucose + 1 glucose. Found in cereals. 2. Sugars can be classified as Intrinsic and Extrinsic sugars. Instrinsic: those who are naturally part of the cellular structure of foods for example fruit. These have no bad effects on health and teeth. Extrinsic: not contained within the cell walls. These may be natural such as honey, or refined such as granulated sugar. These are called Hidden sugars. 3. Sources of Sugars Milk • Fruit and vegetables Honey • Cereals Table sugar • Icing sugar Jams • Chocolate Ice-cream 4. A diet high in sugar can lead to: Tooth decay Sugars are the major cause of tooth decay. When sugar is eaten, acid is produced which attacks the enamel surface of the tooth, gradually causing a hole. If the acids are allowed to stay in the mouth for long periods of time, tooth decay develops. Obesity Sugary foods give lots of energy because they are high in calories and low in fibre. Eating too much of these foods means that excess is stored as fat, leading to an increase in body weight. Diabetes This is a condition in which the body (pancreas) is not able to convert, or becomes less efficient in converting, glucose in the blood into energy. As a result, the amount of glucose in the blood starts to rise. Glucose is obtained from the digestion of carbohydrates. Eat carbohydrates Rise in blood glucose level Insulin (produced in the _________) to controls level of glucose in blood Starch Starch is formed by many glucose units joined together, as they are more complex than sugars it is called complex carbohydrates. 1. Importance of starch in the diet: Starch is very healthy and helps to keep blood sugar levels constant. Starchy foods provide other nutrients as well as starch such as calcium, iron, B Vitamins. Ms. J. Borg -2- Cookery and Nutrition Beginners When we eat more starchy foods it helps to cut down on fatty foods as starch fills us up quickly. Protein Proteins are made up of long chains of building block called amino acids. 1 gram of protein gives us 4 Calories Protein should be 15% of our daily energy intake 1. The functions of protein Every cell in our body contains some protein. Protein is needed for growth and repair of body tissue, muscles and blood cells. 2. Essential and Non- Essential Amino Acids There are 20 amino acid which make up proteins. Our bodies can make eleven amino acids; therefore they are called- NON- ESSENTIAL AMINO ACIDS/Dispensable Amino Acids. We need to obtain other nine amino acids and these are called ESSENTIAL AMINO ACIDS/ Indispensable Amino Acids. 3. Sources of proteins ANIMAL ORIGIN Meat, fish, poultry, eggs, milk and milk products. These contain all the essential amino acids. PLANT ORIGIN Peas, beans, lentils, cereals, nuts and seeds. These foods tend to lack one or more of the essential amino acids. However, there is an exception – Soya beans contain all of them. 4. Novel Sources of protein Soya beans are used to make T.V.P.-Textured Vegetable Protein which is shaped, flavoured and coloured to look like meat. This is suitable for vegetarians. Qourn which is made from mycoproteins. They are high in protein and low in fat, used as alternatives to meat. Tofu: is a foodmade by coagulating soy milk, and then pressing the resulting curds into blocks. 5. Complementary proteins LOW BIOLOGICAL VALUE- LBV. Vegetables foods which are good source of protein usually lack one or more of the Ms. J. Borg -3- Cookery and Nutrition Beginners essential amino acids needed by humans, so proteins from a single vegetable food are said to have a low biological value- LBV. Mixtures of proteins from plant foods taken together can complement each other by supplying the full range of amino acids needed by humans. Example of complimentary protein meals are: ♥Beans on toast ♥ Rice and peas ♥ Kidney beans and rice HIGH BIOLOGICAL VALUE, HBV. Animal protein from meat, fish, milk, cheese and eggs supply all the essential amino acids and are said to have a high biological value, HBV. 6. Protein 8. Dangers of high protein slimming diets The human body needs a source of energy and carbohydrates are the best source of energy available to us. In the absence of carbohydrate, the human body is forced to burn dietary fat (therefore you will lose weight) and protein to fulfill its energy needs. The breakdown products of burning large quantities of body fat for fuel are called ketones. They will begin to accumulate in the body. A build-up of ketones in the body can cause all kinds of damage to vital organs such as the liver and the kidneys. This process is called ‘ketosis’. Fats and Oils o Fats are solid at room temperature while oils are liquid at room temperature. o Fats are made out of 3 elements which are carbon, hydrogen and oxygen. o Fat is present in food either as visible (that can be seen) or invisible (that cannot be seen). 1. Types of fats Fats are made of Essential Fatty Acids (EFA’S). Fatty acids are the building blocks of the fat in our bodies and in the food we eat. During digestion, the body breaks down fats into fatty acids, which can then be absorbed into the blood. Fatty acids have to be ingested since the body cannot produce these. a. Saturated fats Are found primarily in animal products – red meat, lard, butter, poultry with skin and whole milk dairy products. Saturated Fats are also found in plant products such as: vegetable oils; palm and coconut. Avocado fruit also contains saturated fat. Ms. J. Borg -4- Cookery and Nutrition Beginners b. Unsaturated fats Monounsaturated fatty acids are found mainly in plant fats and oils especially olive oil and polyunsaturated fatty acids are found mainly in vegetable oils and fish oils. Omega Fatty Acids Omega-3 fatty acid is an essential fatty acid that plays an in brain function and may help you fight against cardiovascular Sources: Grains, Brazil Nuts, Mustard Seeds, Pumpkin Seeds, Vegetables, Walnuts, Fish Oils, and flaxseed. important role disease. Green Leafy Omega-6 plays a crucial role in brain function, as well as normal growth and development. Sources: Olive Oil, Sesame Oil, Pumpkin Seeds, Safflower Oil, Sunflower Oil, Raw Nuts & Seeds. Trans fatty Acids (Trans fats/ TFA) and Hydrogenation Trans fats are made by a chemical process called hydrogenation. Liquid vegetable oil (an otherwise healthy monounsaturated fat) is packed with hydrogen atoms and converted into a solid fat. This is common in margarine and shortening. These fats also raise blood cholesterol. 2. Fats recommendation 30% of our energy intake should be supplied from fats. Saturated fats should be less than 10%! Remember 1 gram of fats gives us 9 kcal. 3. Functions of fats It is a good source of energy. A layer of fat is stored around certain vital organs protects them from damage (e.g. kidneys). It is needed by all body cells. It provides us with Vitamins A, D, E and K. Forms an insulating layer under the skin which helps to keep us warm. Fat gives a good ____________to foods. 4. What happens if we eat too much fat? a. We become Obese (Obesity -being very overweight) Diets high in fat tend to result in obesity as fat provides a lot of calories. Obesity raises blood cholesterol. Obesity may also lead to high blood pressure and heart disease. ( stroke, heart attack, heart failure) To lower the blood cholesterol level eat more starchy carbohydrates or unsaturated fats instead of saturated fats. Ms. J. Borg -5- Cookery and Nutrition Beginners b. High cholesterol level & High blood pressure High blood pressure results when the blood has difficulty travelling through the arteries and veins due to narrowing. Arteries harden due to the build up of deposits of cholesterol and other fatty substances that form plaque and in turn narrow the arteries. The heart then finds it difficult to pump blood around the body at the required rate. Untreated high blood pressure may lead to stroke or heart attack. c. Heart Disease There is a strong link between the intake of high levels of fats (especially saturated) in the diet and coronary heart disease (CHD). What happens? A diet high in saturated fats leads to a buildup of fatty deposits on the inner walls of the arteries, restricting the flow of blood through them. If a small blood clot forms in the coronary artery, which takes the blood to the heart, it can totally block this narrowed artery causing a heart attack. A blood clot which blocks the artery leading to the brain can cause a stroke. Vitamins Fat soluble Water Soluble Vitamin B Vitamin A Vitamin C The water soluble vitamins dissolve in water and tend to be excreted every day in urine. This means that foods rich in these vitamins need to be eaten regularly. Water-soluble vitamins cannot be stored in the body. Vitamin D Vitamin E Vitamin K Fat-soluble vitamins can usually be stored in the body in the liver. Ms. J. Borg -6- Cookery and Nutrition Beginners 1. Water Soluble Vitamins Vitamin Function Good sources Deficiency Thiamin (B1) Helps the release of Fortified breakfast energy from nutrient in cereals, meat, liver, every cell in the body. milk and milk products, eggs and vegetables including potatoes. Slows growth and development. Mild deficiencies cause tiredness and depression. Sever causes beriberi. Riboflavin (B2) Needed for healthy skin. Helps the release of energy to cells and in the body’s use of carbohydrates. Slows down growth and development. May cause skin and eye problem. Niacin (B 3) Involved in the energy Meat, especially offal, Sever deficiency causes producing reactions in cereals, potatoes and pellagra. Symptoms cells. Helps the nervous bread include diarrhoea, system and healthy skin. dementia and dermatitis. Cereals, nuts, milk and milk products, meat, liver kidney, eggs, lean meat and green vegetables. All animal foods- liver, Helps prevent certain fish, meat, cheese, milk Can lead to anaemia and forms of anaemia. Helps and eggs. Fortified neurological problems. cells to divide. breakfast cereals. B12 Folic acid (b 9) Deficiency in the early stages of pregnancy is associated with several tube defects. Needed for red blood cells production Meat, especially offal, shellfish, cereals, beans, legumes and dark leafy vegetables. Mild deficiency leads to tiredness. A deficiency may cause anaemia. Needed in pregnancy to prevent neural tube defects, such as spina bifida. VitaminCAscorbic Acid Maintains body’s connective tissue, important for wound heeling. Helps iron absorption. Fruits and vegetables, especially citrus fruit including oranges and lemons. Scurvy (Antioxidant) Vitamin B helps the release of energy from carbohydrates. Scurvy: swollen and bleeding gums with loosened teeth, soreness and stiffness of the joints and lower extremities, blee under the skin and in deep tissues, slow wound healing, and anaemia. Ms. J. Borg -7Beriberi: affects many systems of the body, including the muscles, heart, nerves, and digestive system. Cookery and Nutrition Beginners What are the effects of heat on B complex Vitamins and Vitamin C? Most of the B Vitamins except Niacin are sensitive to heat so can be lost by cooking. They can also be lost by dissolving into cooking water. Thiamin (Vitamin B1) and Vitamin C (ascorbic acid) are the most easily lost of all the vitamins. Vitamin C is quickly and easily destroyed by: Heat Exposure to air The presence of alkali such as bicarbonate of soda Water 2. Fat Soluble Vitamins Vitamin Vitamin ARetinal Use by the body Good sources Deficiency Good for night vision, healthy skin and tissue. Animal origin- liver, oily fish, milk, butter, margarine and cheese. Long-term deficiency may lead to night blindness. Excess may lead to liver and bone damage. Beta carotene (Antioxidant) Vitamin D - Cholecalciferol Vitamin E- Tocopherol (Antioxidant) Is an antioxidant vitamin which might protect against cancers Helps the absorption of Calcium to from healthy bones and teeth. Vegetable origincarrots, green vegetables, orange and red fruit and vegetables. Mostly available by exposure to sun. Found in margarine, oily fish, and liver. Good for healthy skin. May help to protect against hearth disease Ms. J. Borg Eggs, nuts, seeds, cereal products, vegetable oils. Deficiency in children can cause rickets. Deficiency rare. -8- Cookery and Nutrition Beginners Vitamin K- Phylloquinone Involved with clotting blood Green vegetables, pulses, fruit and cereals, meat, liver. Also made by bacteria in the large intestines. Deficiency rare. Antioxidants (Vitamin A, C and E) They are vitamins, minerals, and other nutrients that protect and repair cells from damage caused by free radicals. Many experts believe this damage plays a part in a number of chronic diseases, including hardening of the arteries, cancer, and arthritis. Rickets: softening of bones in children potentially leading to fractures and deformity. Ms. J. Borg -9-