What do we feed ourselves for?
Thinking about everything we do during the day (walking, running, jumping, thinking…) and what our body does (breathing, hearing, seeing…) while the blood circulates through the body performing very important functions; We understand that our body works continuously, even when we sleep. This is why man, like all living beings, needs feed to:
- Replace the losses of living matter consumed by the activity of the organism.
- Produce the substances necessary for the formation of new tissues, promoting growth.
- Transform the energy contained in food into heat, movement and work.
Classification of foods by their origin:
Foods by their origin are classified into three groups:
- Those of vegetable origin: vegetables, fruits, cereals.
- Those of animal origin: meat, milk, eggs.
- Those of mineral origin: mineral waters and salts.
Each of these foods provide our body with substances that are essential for its functioning and development.
These substances are:
- Carbohydrates (bread, flour, sugars, pasta), of high energy value.
- Proteins (meat, eggs, dairy, legumes) necessary for the growth and formation of tissues.
- The energy-producing lipids (fats and oils).
- Waters and mineral salts in variable proportions for the balance of the body's functions.
- Vitamins, complex chemical substances, in minimal quantities, but essential for the good state of the organism.
Classification of foods by their description
- Dairy foods (milk, casein, cream, butter, cheese)
- Meat and related foods (meat, eggs)
- Farinaceous foods (cereals, flours)
- Plant foods (vegetables, and fruits)
- Sugary foods (sugars, honey)
- Fatty foods (edible oils, edible fat, margarine)
- Beverages (alcoholic or non-alcoholic beverages, syrups, vegetable juices, fermented beverages, wines and related products, liqueurs)
- Stimulating and fruitive products (cocoa and chocolate, coffee and substitutes, tea, yerba mate)
- Corrective agents and adjuvants (spices or vegetable seasonings, edible mushrooms, yeasts, ferments and derivatives, salt and compound salts, sauces, dressings or dressings, vinegars)
- A good diet must be balanced and complete, that is, all the aforementioned groups must be present and cover all the needs of the individual.
What are nutrients?
Nutrients or food principles are all the normal constituent substances of food, for example, the starch of vegetables, the fat of milk, etc.
The essential nutrients or nutritional principles are substances that make up the organism, whose absence from the regime or its reduction below a minimum limit, causes a deficiency disease after a variable time. Examples of essential nutrients are: some amino acids, vitamin A, iron, calcium, etc.
To be healthy, people need to consume different foods and liquids. The Staple Food Pyramid describes the quality and the amount of the daily food we need to obtain the necessary nutrients.
Basic Food Pyramid: Servings Per Day
Types of food
The foods They can be classified into breads and cereals, legumes or legumes, tubers and rhizomes, fruits and vegetables, meat, fish, eggs; milk and derivatives, fats and oils, and sugars, jams and syrups.
The group of breads and cereals includes wheat, rice, corn and millet. They are rich in starches and are an easy and direct source of calorie supply. Although protein is not abundant in whole grains, the large amount consumed provides significant amounts, which, however, must be supplemented with other foods rich in protein to obtain all the essential amino acids. White wheat flour and refined rice are low in nutrients, but like all whole grains that contain the germ and the outer layer of the seed, wheat and rice provide fiber to the body: the B vitamins thiamine, niacin and riboflavin, and the minerals zinc, copper, manganese, and molybdenum.
Legumes include a wide variety of beans, peas, lentils and grains, and even peanuts. All of them are rich in starch, but provide much more protein than cereals or tubers. The ratio and type of amino acids in legumes are similar to those in meat. Its amino acid chains often complement those of rice, corn and wheat, which are the staple foods of many countries.
Tubers and rhizomes include various types of potato, cassava, and taro. They are rich in starch and relatively low in protein, but they provide a wide variety of vitamins and minerals.
Fruits and vegetables are a direct source of many minerals and vitamins that are lacking in cereal diets, especially vitamin C from citrus fruits and vitamin A from carotene in carrots and leafy vegetables. Sodium, cobalt, chlorine, copper, magnesium, manganese, phosphorus and potassium are present in vegetables. The cellulose in vegetables, which is almost impossible to digest, provides the necessary support to pass food through the digestive tract. Many of the more fragile water-soluble vitamins are found in fruits and vegetables, but they are easily destroyed by overcooking.
Meat, fish and eggs provide all the essential amino acids that the body needs to assemble its own proteins. Meat contains 20% protein, 20% fat, and 60% water. Organ meats are rich sources of vitamins and minerals. All fish contain a high percentage of protein, and the oils in some of them are rich in vitamins D and A. Egg white is the most concentrated form of protein that exists.
La leche y sus derivados incluyen la leche entera, el queso, el yogur y los helados, todos ellos conocidos por su abundancia en proteína, fósforo y en especial calcio. La leche también es rica en vitaminas, pero no contiene hierro y, si es pasteurizada, carece de vitamina C. Aunque la leche es esencial para los niños, su excesivo consumo por parte de los adultos puede producir ácidos grasos insaturados que se acumulan en el work circulatorio.
Fats and oils include butter, shortening, tallow, and vegetable oils. They are all high in calories, but apart from butter and some vegetable oils like palm oil, they contain few nutrients.
Sugars, jams and syrups are consumed in large quantities in some countries, where they constitute a large part of the carbohydrate intake. Honey and maple syrup are made up of more than 75% sugar and contain few nutrients. Consuming too much sugar causes tooth decay.
In general, scientists recommend the following: eat a variety of foods; maintain the ideal weight; avoid excess fats and oils, saturated fats and cholesterol; eat foods with enough starch and fiber; avoid excess sugar and sodium, and, if you drink alcohol, do so in moderation.
Nutrients are classified into five main groups: proteins, carbohydrates, fats, vitamins, and minerals. These groups comprise an approximate total of between 45 and 50 substances that scientists consider essential to maintain health and normal growth. In addition to water and oxygen, they also include about eight protein constituent amino acids, four fat-soluble and ten water-soluble vitamins, about ten minerals and three electrolytes. Although carbohydrates are a source of energy, they are not considered essential, since proteins can be transformed for this purpose.
It is the amount of heat necessary to raise the temperature of 1 gram of water from 14,5 to 15,5 ° C. Sometimes another temperature range is specified. The most common definition in thermochemistry is that 1 calorie is equal to 4,1840 joules (J).
Engineering uses a somewhat different calorie, the international calorie, which is equal to 1/860 watts / hour (4,1868 J). A large calorie or kilocalorie (Cal), often also called a calorie, is equal to 1.000 calorie-grams, and is used in dietetics to indicate the energy value of food.
In energy metabolism, the unit used is usually the kilocalorie, which is the amount of energy required to raise the temperature of 1 kg of water by 1 ºC. Carbohydrates have an average content of 4,1 kilocalories (17 joules) per gram; proteins of 4,2 (17,5 joules), and fats of 9,3 kilocalories (39 joules).
Carbohydrates are the most abundant type of food in the world, while fats are the most concentrated fuel and the easiest to store. If the body depletes its stores of fats and carbohydrates, it can use protein from the diet directly or break down its own protein tissue to generate fuel. Alcohol is also an energy source that produces calories per gram. The body's cells cannot oxidize alcohol, so the liver has to process it into fat, which is then stored in the liver itself or in fat tissue.
The primary function of protein is to produce body tissue and synthesize enzymes, some hormones such as insulin, which regulate communication between organs and cells, and other complex substances, which govern the processes, bodily. Animal and plant proteins are not used in the same way that they are ingested, but must be broken down by digestive enzymes into amino acids that contain nitrogen.
It is easy to have proteins of animal or vegetable origin. Of the 20 amino acids that make up proteins, eight are considered essential (leucine, isoleucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine), they must be taken ready through food. If these essential amino acids are not present at the same time and in specific proportions, the other amino acids, all or part, cannot be used to build human proteins. Therefore, a diet that contains these essential amino acids is very important to maintain health and growth.
When there is a lack of any of them, the other amino acids become energy-producing compounds, and their nitrogen is excreted. When excess protein is ingested, which is common in countries with high-meat diets, the extra protein is broken down into energy-producing compounds.
Since proteins are much more scarce than carbohydrates, although they also produce 4 calories per gram, ingesting excess meat, when there is no demand for rebuilding tissues in the body, is an ineffective way to provide energy. Animal foods contain complete proteins because they include all the essential amino acids. In most diets it is recommended to combine proteins of animal origin with vegetable proteins. It is estimated that 0,8 grams per kilo of weight is the healthy daily dose for normal adults.
Además de intervenir en el crecimiento y el mantenimiento celulares, las proteínas son responsables de la contracción muscular. Las enzimas digestivas son proteínas, al igual que la insulina y casi todas las demás hormonas, los anticuerpos del work inmunológico y la hemoglobina, que transporta oxígeno en la sangre. Los cromosomas, que transmiten los caracteres hereditarios en forma de genes, están compuestos por ácidos nucleicos y proteínas.
Many diseases and infections cause a continuous loss of nitrogen in the body. This problem must be compensated with a higher consumption of dietary protein. Children also require more protein per kilogram of body weight. A protein deficiency accompanied by a lack of energy gives rise to a form of protein-energy malnutrition known as marasmus, which is characterized by loss of body fat and muscle wasting.
Inorganic minerals are necessary for the structural reconstruction of body tissues as well as participating in processes such as the action of enzyme systems, muscle contraction, nervous reactions and blood clotting. These mineral nutrients, which must be supplied in the diet, are divided into two classes: macro elements, such as calcium, phosphorus, magnesium, sodium, iron, iodine and potassium; and micro elements, such as copper, cobalt, manganese, fluorine and zinc.
Calcium is necessary for building bones and keeping them stiff. Milk and its derivatives are the main source of calcium.
Phosphorus, also present in many foods and especially in milk, combines with calcium in bones and teeth. It plays an important role in energy metabolism in cells, affecting carbohydrates, lipids and proteins.
Magnesium, present in most foods, is essential for human metabolism and very important for maintaining the electrical potential of nerve and muscle cells.
Sodium is present in small amounts in most natural products and is abundant in prepared foods and salty foods. It is also present in the extracellular fluid, where it has a regulatory role. Excess sodium produces edema, which consists of a super accumulation of extracellular fluid. There is now evidence that excess salt in the diet contributes to raising blood pressure.
El hierro es necesario para la formación de la hemoglobina, pigmento de los glóbulos rojos de la sangre responsables de transportar el oxígeno. Sin embargo, este mineral no es absorbido con facilidad por el work digestivo. En los hombres se encuentra en cantidades suficientes, pero las mujeres en edad menstrual, que necesitan casi dos veces más cantidad de hierro debido a la pérdida que se produce en la menstruación, suelen tener deficiencias y deben tomar hierro fácil de asimilar.
Iodine is essential for the synthesis of hormones in the thyroid gland. Its deficiency produces goiter, which is an inflammation of this gland in the lower part of the neck. Insufficient iodine intake during pregnancy can lead to cretinism or mental deficiency in children.
Micro elements are other inorganic substances that appear in the body in minute quantities, but are essential for good health. Little is known about their operation, and almost everything that is known about them refers to the way in which their absence, especially in animals, affects health. Micro elements appear in sufficient quantities in almost all foods.
Among the most important micro elements is copper, present in many enzymes and proteins, which contains copper, from the blood, brain and liver. Copper insufficiency is associated with the inability to use iron for the formation of hemoglobin. Zinc is also important for the formation of enzymes. Zinc deficiency is thought to impede normal growth and, in extreme cases, lead to dwarfism. Fluoride, which is deposited mostly in bones and teeth, has been found to be a necessary element for growth in animals. Among the other micro elements we can mention chromium, molybdenum and selenium.