1. FOOD AND NUTRITIONAL SUBSTANCES 1.1. Nutrients 1.2. Groups of foods2. A COMPLETE AND BALANCED DIET 2.1. Criteria for an adequate diet
Nutritional substances are those chemical compounds which are found in food andwhich we use to obtain energy and to build the matter which goes to make up our cells. NUTRITIONAL SUBSTANCES GLUCIDS LIPIDS (also called MINERAL SUGARS OR PROTEINS WATER VITAMINS or SUBSTANCES CARBOHYDRATES) FATS
NUTRIENTS MACRO-NUTRIENTS MICRONUTRIENTS We need very small quantities They are the majority of these substances, but their components of food absence causes serious disorders. MINERALGLUCIDS LIPIDS PROTEINS WATER FIBRE VITAMINS SALTS
MACRO-NUTRIENTS:a.1.) Glucids or carbohydrates: a.2.) Lipids or fats: their main function in the body is they have many functions, but the to provide energy. The most most important is that of providing common glucids in our diet are energy. They are, together with starches which can be found in proteins, which form the cellular pulses, potatoes, etc., and simple sugars like glucose and membrane of the cells. saccharose. Some examples of pulses: chickpeas, beans, … They can be found in vegetable oils (olive oil, sunflower oil, etc.) and in animal fats (lard, fat and butter).
a.3.) Proteins: these are necessary for building the matter that forms r cells. We can obtain proteins from foods which have an animal originmeat, fish and eggs) and a vegetable origin (pulses, cereals, etc.) a.4.) Water: it is a fundamental a.5.) Fibre which comes from component of living matter. vegetables is also a glucid. It is necessary for helping the food to We need to take three litres pass through the intestine. of water a day: one and half litres comes from food and the rest we must drink.
b) MICRO-NUTRIENTSb.1.)The most well-known b.2.)Minerals are also micro-nutrients are micro-nutrients, chemical vitamins. We need very elements that we also small quantities of these substances, but their need in small quantities. absence causes serious Examples: iron (blood), disorders. magnesium, sodium, potassium, phosphorous, fluoride, etc. EXAMPLES OF VITAMINS VITAMINS Foods where they are foundA( retinol) Carrots, spinach, parsleyB1 (thiamine) Eggs, peanuts, pulses Sardines and freshB6 (pyridoxine) anchovies, lentils Kiwis, red peppers, citrusC (ascorbic acid) fruitsD (calciferol) Produced by the skin
1.2. Groups of foods There are different ways of grouping together the food we needfor a healthy diet: the “FOOD WHEEL” or the “FOOD PYRAMID” aresome examples. They help us to choose the adequate food.We are going to classify as Grande Covian did. He was a Spanishnutritionist. This classification divides food into six groups, according toboth their origin and their nutrients.
The six groups are as follows:GROUP 1. MILK, MILK DERIVATES AND GROUP 2. MEAT, POULTRY AND EGGS FISHThese are a source of proteins, vitamins and Basically, these provide us with calcium. proteins. GROUP 3. FATS AND OILS GROUP 4. CEREALS, PULSES, POTATOES AND SUGARS These include animal fats like butter and vegetable oils. Eaten in moderation they provide the lipids we need. These provide proteins and glucids
GROUP 5. VEGETABLES GROUP 6. FRUITThese are a source of vitamins and fibre These provide glucids, vitamins and fibre
An optimum diet is a complete and balanced diet,complete because it uses foods from each group andbalanced because we eat the correct proportion of eachfood.The diet varies in each person: the work, the age, illnesses,… andmany other factors have influence on dietsTo know if our diet is complete and balanced or not, wemust use some criteria. A COMPLETE AND BALANCED DIET (AUDIO): http://lgfl.skoool.co.uk/content/keystage3/biology/pc/learningsteps/ABDLC/launch.html
2.1.Criteria for an adequate dietDiet should comply with the following key points:- Food should provide just the right amount of energy for carrying out our activities and for the development of the organism. An excess or defect in this energy supply will be harmful.- Diet should supply enough proteins, vitamins and minerals. Once again, an excess or defect in this energy supply will be harmful.- With regard to the distribution of the foods which provide energy, this should be done as follows: DISTRIBUTION OF FOOD FOOD PROPORTION Rich in glucids 55-60% of total number of calories Rich in lipids 30% of total number of calories Rich in proteins 15% of total number of calories
Other criteria to bear in mind: We must eat 22 g of fibre a day which can be obtained from vegetables and fruits You should not eat more than 3g of salt a day. Any excess may cause problems in the excretory apparatus and increases blood pressure. Only 10% of calories should be obtained from simple glucids (sugars). The maximum level of cholesterol per day is 300 g. An excess of this can cause serious problems in the arteries. Combine animal and vegetable proteins. However, as you know, the most serious problems are brought through malnutrition. A poor diet with little variation can cause serious illnesses. MALNUTRITION: http://lgfl.skoool.co.uk/content/keystage3/biology/pc/learningsteps/MALLC/launch.html
Now is your turn! Make a “FOOD WHEEL” or a “FOOD PYRAMID” for a person of your age following the criteria of a balanced diet.