Healthy Diet Composition Essay Example
From the first days of life, all processes in the human organism are largely dependent on the composition of food diet. During life, every person constantly demands nutritional materials received with food. Much of these nutriments are “burned” (oxidized) in the body, thereby releasing energy. The body uses this energy to maintain a constant body temperature, to ensure normal functioning of internal organs (heart, respiratory system, circulatory organs, nervous system, etc.), and especially to perform physical work. Furthermore, so-called plastic processes associated with the formation of new cells and tissues flow continuously in the body. It is essential that all these body energy demands are compensated to maintain life. The source of such compensation is nutriments from food. Proper composition of food, that is the appropriate intake of proteins, fats, carbohydrates, vitamins, minerals, and water, plays an important role in preservation of health and improper diet in turn leads to violation of health.
Foodstuff should contain proteins, carbohydrates, fats, minerals, vitamins, and water. Among children, the need in the total amount of food and nutrients depends primarily on age and among adults it depends on the type of work and living conditions. To better meet needs of the organism, it is necessary to know how much energy it demands per day. It has been found that the energy formed in a body is eventually released as heat. Therefore, by the amount of heat released in the body, one can determine its energy demands; these demands are usually expressed in heat units, great calories, or kilogram-calories (great calorie is an amount of heat required to heat 1 kg of water for 1°C). Thus, for example, during one hour of sleep a person spends 0.93 calories per 1 kg of body weight and for dressing and undressing 1.69 calories (Williams 173).
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Under the term “the best nutritional standard”, one understands the standard that covers all spending in the organism and, furthermore, that provides children with sufficient nutrients for normal growth and development. It has been found that one can divide population into 4 groups according to energy demands: the first group (energy demands of 3,000 kcal per day) includes people who are not associated with physical labor and work mainly in a sitting position. The second group includes workers of mechanized labor (demands of 3,500 kcal per day). The third group includes not-mechanized or not fully mechanized labor (demands of 4,500 – 5,000 kcal per day). In case of sport activities, energy expenditures, especially during training and competitions, can increase up to 6,000 – 7,000 kcal per day (Williams 191).
In order to properly build the diet, it is not enough to determine only energetic demands of an organism. One should also know what nutrients and in what amount provide this calorific value, i.e. to determine qualitative composition of food. During the oxidation of 1g of carbohydrates or 1g of proteins, 4.1 kcal are produced in the body and during the oxidation of 1g of fat this amount increases to 9.3 kcal (Williams 197). If it is necessary, fats and carbohydrates may partially replace each other; but as to proteins, they cannot be replaced by any other nutrient.
The Role of Protein in the Diet
Sources of protein are products of animal and vegetable origin: meat, milk, fish, eggs, bread, cereals, some fruits, and vegetables. Proteins are not similar in their chemical composition and nutritional value. Constituent parts of proteins are simple chemical compounds like amino acids, the amount of which and combinations of which influence nutritional value of the protein. Most complete proteins are proteins of animal origin (Biesalski 512). However, among the products of vegetable origin there are also sufficient sources of protein. Thus, cereals contain from 6 to 16% protein; the most valuable proteins are contained in buckwheat, oatmeal, rice, and some legumes, particularly soybeans (Jones 23). Fruits and vegetables contain only 1.2 – 1.5% of proteins (Jones 23). Proteins of potatoes and vegetables, especially cabbage, contain vital amino acids in the same proportions as animal proteins. Thus, the wider variety of food a person consumes, the more proteins of sufficient quality and, consequently, a sufficient amount of essential amino acids he/she gets.
The need for proteins depends on person’s age, type of activity, and state of the body. Development and growth of growing organisms depend on the protein quantity and quality. The child’s need for protein depends not only on age, but also on the state of an organism, on previous infectious diseases, and the nutrition from the first months of life. Children lagging in physical development need larger amounts of protein than normally developing children. For the youngest children’s nutrition, the amount of animal protein is nearly 100%, for children from 1 year to 3 years – 75%, and for all children and adolescents the amount should not be less than 50% (Jones 27). Adults need the amount of protein of the animal origin to be not less than 30%. It is essential that proteins are to be in the right proportion with other food substances – vitamins, carbohydrates, and fats. In the absence or lack of carbohydrates, fats, and vitamins, protein digestion processes are significantly enhanced and recommended daily protein intake may be insufficient.
In the human organism, there is a continuous oxidation of substances or, as it is said, “burning”. “Combustible” or energetic substances are primarily carbohydrates and fats and to a lesser extent proteins.
The Role of Fats and Carbohydrates
In the body, fat is kept in the form of fat reserves in the so-called fat depots: subcutaneous tissue, gland; fat sometimes is kept in some internal organs such as liver and kidney. Fat storage takes place not only from fat food, but also with abundant carbohydrate diet (flour products, cereals, vegetables, sugar, etc.) as a result of carbohydrates transfer into fat (Williams 320). With abundant protein diet, substantial amounts of fat are also deposited. Thus, fat in the body can be formed from dietary protein.
The excess of fat reduces digestibility of food, in particular its protein, and results in the creation of a large amount of toxic substances in the body. However, too little fat affects the quality of food and its taste and leads to a decrease in accessibility of all nutrients. More than that, fats are the only source of fat-soluble vitamins, which play a very important role in the vital activity of the organism. Therefore, the lack of fat in food can cause serious disturbances in metabolism. Depending on the overall caloric intake, one recommends to consume from 75 to 110g of fat per day for an adult, wherein at least one third should be animal fats, in particular milk fat (Williams 347). In addition to animal fats, the diet must contain vegetable fats since they contain very important substances for the body, the so-called unsaturated fatty acids (oleic, linoleic, arachidonic, etc.). Due to the fact that fats have higher calories than proteins and carbohydrates, fat availability allows regulating the amount of food. When one replaces fat with carbohydrates, the amount of food increases since in order to save caloric intake, it is necessary to take two and a half times more carbohydrates than fat. In the North, fats play a particularly important role as they give an opportunity to increase caloric intake without increasing significantly its volume.
Sources of carbohydrates are mainly herbal products, bread, cereals, potatoes, vegetables, fruits, and berries. Among the products of animal origin, milk (milk sugar) contains carbohydrates. Nutrition products contain various carbohydrates. Cereals and potatoes contain starch, which is a complex substance (complex carbohydrate) insoluble in water, but cleaved by digestive juices into simpler sugars. In fruits, berries, and vegetables, carbohydrates are in the form of various simpler sugars like fruit sugar, beet sugar, cane sugar, grape sugar (glucose), and others (Bamforth 259). These substances are soluble in water and are well-absorbed in the body. Water-soluble sugars are rapidly absorbed into the bloodstream. It is advisable not to intake all the carbohydrates in the form of sugars, but to intake the most part in the form of starch (Bamforth 259). This contributes to the gradual delivery of sugar to tissues. It is recommended to intake only 20-25% of the total amount of carbohydrates contained in the daily diet as sugar. This figure includes sugar found in sweets, pastries, fruits, and berries.
If carbohydrates come from food in sufficient quantities, they are kept mainly in the liver and muscles in the form of a special animal starch called glycogen. Subsequently, glycogen stock splits to glucose, getting in the body, the blood, and other tissues and being used for the needs of the organism. During superfluous nutrition, carbohydrates are transferred to the body fat. As a rule, one refers fiber (plant cell membrane) to carbohydrates, which is little used by the human body, but is necessary for proper digestion.
The Role of Vitamins
The role of vitamins in the diet is extremely high; like all nutrients, they are of utmost importance for the body and are used in metabolic processes. If a person does not receive one or more vitamins with food, serious violations or the so-called beriberi take place (Williams 439). Considerable violation can occur in those cases when an inadequate amount of vitamins gets to the body for a long time.
The Role of Minerals
The body continuously consumes minerals and the volume of these demands depends on the type of activity, working conditions, the state of the body, etc. In case food is varied, then it contains a sufficient number of all required minerals (magnesium, salt of calcium, phosphorus, potassium, iron, copper, and others) (Flynn et al. 122). Salts of calcium and phosphorus are the main components of the skeletal system; moreover, phosphorus is a part of the neural and other tissues. The best sources of calcium are milk, milk products, whey, and cheese. Phosphorus gets into the body with products of animal and vegetable origin and is well-digested; phosphorus compounds derived from animal products (liver, brains, meat, cheese, eggs) are used much better and have a beneficial effect on the nervous system, especially during intense mental work. Salts of calcium and magnesium are important for proper operation of the heart muscle and the musculoskeletal system in general. Sources of magnesium salts include rye bread, cereals, and bran. Salts of potassium contribute to the removal of water through the kidneys and regulation of the water content in tissues. This is particularly important in case of cardiac weakness and hypertension, as well as violations of the cardiovascular system (Flynn et al. 127). Sources of potassium salts are various vegetables such as cabbage and potatoes. Iron salts are present in the colorant composition of blood (hemoglobin) and help to transfer oxygen from the lungs to tissues. In addition, copper salts are of great importance for the process of blood-forming. Foods rich in iron include beef, egg yolk, rye, wheat bread from wheat flour, liver, kidney, and others.
Salt, which many consider only as flavoring, is also of great importance for the organism. If the body does not receive salt for a long time, it causes severe painful phenomena like dizziness, fainting, cardiac disorder, etc. However, excessive intake of salt affects the state of the cardiovascular system, the kidneys, and other organs.
The Role of Water
There is no living cell that can exist without water. Water is present in all organs and tissues of the body. The body of an adult contains 60-65% water (Williams 410). All processes in the body are associated with the presence of water and with soluble substances in it. It is known that a person can exist for a long time (a month or more) without food, but without water he/she dies within a few days.
A significant amount of water is contained in foods, ready meals; moreover, water is consumed as drinking water. It has been found that all water received with food and drinks per day, on average, equals to 2-2.5 liters (Williams 427). This amount of water must be considered as the daily norm for humans. It is not recommended to use the excessive amount water as drinking plenty of fluids enhances functioning of the heart and kidneys.
For the processes of absorption to occur with maximum intensity and the body to make a full use of the substance from food, it is necessary not only to build the nutrition in accordance with the age and type of activity, but also to ensure the correct dietary regimen. One should eat only at fixed hours. It is significant since the activity of digestive glands in such cases begins before meals. Dining at different times leads to the breakdown of the established operation of the nutritional glands. For an adult, the most rational regime of eating is four meals daily or at least three meals daily. Deviations from such a diet should take place only for the patient during recovery periods after serious illnesses when the appetite has not returned yet. In such cases, one should have five and even six meals daily in order for the sick person to get a sufficient amount of food with frequent eating.
For an adult person, food should be distributed as follows: breakfast 30% of daily calories, for lunch 45 – 50%, and for dinner 20 – 25% (Waxman 162). Distribution of food for a four meals regime: lunch – 45% and dinner – 20% of the daily diet. At the same time, food rich in protein (meat, fish, and beans) should be consumed during the most active part of the day, but not before bedtime. During sleep, digestive processes slow down and, therefore, consumption of the protein food before bedtime can lead to the worsening of digestibility. The last meal should be at least three-four hours before bedtime. However, for many it is useful to drink a glass of milk or have a yogurt or tea with bread or biscuits one-two hours before bedtime. This is especially important for people suffering from gastro-intestinal or cardio-vascular diseases.
Proper diet regimen promotes work ability and is the most important condition for the normal activity of the gastrointestinal tract. Such illnesses as gastritis, duodenal ulcer, and chronic colitis are often the result of improper diet and lack of established eating habits. In the construction of a balanced diet, one should note that meals should leave a feeling of satisfaction. This is achieved during eating when the appetite appears and after a meal there should be the feeling of satiety for a certain period of time. The feeling of saturation depends on several factors: the amount and composition of food, the amount of gastric juice, as well as how the food meets established habits of a person. If a person is accustomed to bulky food, he/she will still be hungry after high-calorie, nutritious, but low in volume meal. A long-term feeling of satiety is caused by meat in combination with a garnish of cooked potatoes, other vegetables, and cereals that are rich in carbohydrates.
Food Diet and Diseases
Food Diet, Weight, and Hormonal Status of the Organism
It is unnatural when food does not serve as source of life, but harms the health. Reasons for harmful effects of food on the body are different. Malnutrition that occurs not only because of the lack of food, but also under the influence of “hungry” diet propaganda are unfavorable to the body. Many people even develop a morbid fear of “becoming fat”. In these cases, they avoid high-calorie foods, artificially induce vomiting, and apply laxatives and diuretics immediately after the meal. Similar measures not only reduce weight, but also can lead to beriberi and other disturbances in the body, particularly in the genital area. Abuse of laxatives and diuretic drugs causes changes in water-salt (electrolyte) exchange. The signs of these disorders include pallor, sweating, tremor of fingers, and muscle tension (Obrosova et al. 2600). In particularly severe cases, seizures resembling epileptic take place. Many people have an increased interest in food, which usually leads to overeating and obesity. The best thing is to keep moderation in everything: not to go hungry and not to overeat, focusing on health and body mass indices.
The foods may contain substances, increased sensitivity to which causes allergies. Currently, one understands allergies as the condition of the body appearing as a result of the interaction of antibodies (immunoglobulin E) and related antigens (Bahna 79). Under the influence of the complex antigen – antibody of certain cells, there are released mediators like histamine, serotonin, and others, directly conditioning itching, spasm of blood vessels and bronchi, urticaria, and other manifestations of allergic reactions (Bahna 79). The antigen, in principle, can be almost any material of internal and external environment, mostly of protein or polysaccharide nature.
Food allergies are associated not only with diseases of the gastrointestinal tract, but also asthma (particularly in children), rhinitis, conjunctivitis, stomatitis, eczema, arthritis, headache, etc (Newell et al. S10). In case of food allergy, after the penetration of the allergen (antigen) in the gastrointestinal tract there is a burning or itching in the mouth, pharynx typically in a few minutes, soon being joined by vomiting or diarrhea and itchy skin. In severe cases, the patient’s blood pressure plummets and the person faints. Allergic reactions to food can be direct (vomiting, diarrhea), secondary (blood loss, iron and protein deficiency), and distant (allergic rhinitis, serous otitis, asthma, hives, eczema, angioedema) (Rowe, Rowe, and Young 1160).
Food and Infectious Diseases
Many foods are an excellent breeding ground for microorganisms; thus, they can play the role of intermediaries in the transmission of infection. For example, through the milk the pathogens of tuberculosis, dysentery, brucellosis, cholera, and other infectious diseases can be transmitted. Pathogens can get into milk at all stages: from cows with udder tuberculosis, mastitis, brucellosis; by people with typhoid fever, dysentery, etc., working on livestock farms, being engaged in the transportation of milk, its sales, and processing; and from consumers who do not follow hygienic rules (Centers for Disease Control and Prevention 749). Eggs also pose a certain epidemiological danger. It would seem that nature has created a good protection against the ingress of microbes: shell, membranes, and so on. However, ubiquitous microbes penetrate these barriers. In addition, the egg surface is almost always contaminated with Proteus, Salmonella, and other pathogenic bacteria. Pathogens of toxic-infections, tuberculosis, helminthiasis can be transmitted via the meat and meat products.
In recent years, it has been found that the food can carry not only the bacteria and helminthic diseases, but also certain viral infections (Flint et al. 700). While viruses reproduce only in living cells, nevertheless, as stated in one of the documents of the World Health Organization, the possibility of viral contamination of food is high since a person comes into close contact with food during processing and distribution (World Health Organization ). Many types of food subjected to semination provide favorable conditions for the survival of viruses. Viral diseases transmitted through food include a form of infectious hepatitis, tick-borne encephalitis, poliomyelitis, and hemorrhagic fevers.
Fats and Food
The problem of food influence on chronic diseases deserves a special discussion. For example, patient’s condition may worsen after eating salty foods in case of hypertension and renal disease. The abundant fatty food leads to an exacerbation of chronic cholecystitis and others. It should be emphasized that there is no junk food; it becomes unhealthy only under certain conditions. For example, in case of overweight, chronic cholecystitis, and in some other cases, fatty foods adversely affect a person, but that does not mean that fat is bad (Traubes 208). The lack of fat in the diet sooner or later leads to the death of the body. Indeed, fat is an essential foodstuff. It performs multiple functions; it is a plastic material, energy concentrate, etc. Fats (lipids) are an extensive class of organic substances. Compared with proteins and carbohydrates, they have more energy. When fat is burned (oxidizing to the end products of metabolism, i.e. water and carbon dioxide), energy is released in 2 times more than during oxidation of the same amount of protein. Fat is the energy accumulated in the body put off as a reserve.
Fat plays an important role in maintaining thermal homeostasis. The adipose tissue, i.e. accumulation of fat tissue of different thickness under the skin, is of particular importance. Subcutaneous adipose tissue is a good thermal insulator. Adipose tissue also protects organs from damage. Fat along with proteins is used in the body as a plastic material for constructing cells and subcellular structures. Vitamins A, D, E, and K are soluble in fat. Fats serve as material for the synthesis of certain hormones in the body (Taubes 320). For example, sterols are the raw material, from which male and female sex hormones of the endocrine glands and hormones of the adrenal cortex are formed.
However, different studies indicate that the nutrition containing mainly food of animal origin leads to an increase in blood cholesterol levels, contributing to the development of atherosclerosis (Fraser 1120S). The disease is characterized by a complex of changes in vessel walls, in which plaques are formed, consisting of lipids (cholesterol, etc.), proteins, carbohydrates, and calcium salts. Arteries, of course, lose their elasticity, the ability to stretch, as well as become fragile and brittle. The amount of blood flowing through arteries is thereby reduced, while the blood supply to organs and tissues deteriorates. It increases the likelihood of blood clots. All this in combination with other factors leads to the development of cardiovascular and other diseases (Fraser 1120S).
Even a slight excess of individual daily caloric needs steadily leads to the accumulation of fat in the body. People suffering from obesity lead a sedentary life; unused energy, in turn, contributes to the accumulation of fat. Superfluous 200kcal increase body weight for 20g (Drewnowski 159). Among those suffering from overweight, there is a high mortality. It should be emphasized that obesity occurs if calories obtained from food are not used, which leads to disruption of the energy balance. “Eaten” calories should be used. Therefore, the basis of the prevention and treatment of obesity is normalization of energy metabolism in the body, which is determined by a balanced diet and exercise.
Sweet Foods – Bitter Retribution
Fat metabolism is closely linked with carbohydrate metabolism. A significant part of carbohydrates meets the energy needs of the body and the value of carbohydrates increases during exercise since working muscles increase their consumption. Carbohydrates are necessary not only as a source of energy. They form the skeleton of amino acids, nucleic acids, as well as are involved in the construction of glycoproteins and immunoglobulins, ATP (Traubes 215).
The structural unit of carbohydrate is glucose. It is rapidly soaked in the gastrointestinal tract into the bloodstream and reaches cells where it is used in the process of biological oxidation. Other simple carbohydrate quickly absorbed into the blood is fructose. Lactose also refers to carbohydrates and is extremely important for the child’s body. Glycogen plays a huge biological role as it is a depot of carbohydrates in the body.
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Excess of carbohydrates unused by muscles and deposited as fat inhibits the glucose absorption, which in turn increases concentration of carbohydrates in the blood, reducing their utilization in the muscle tissue. The more a person eats sugar, the more carbohydrate and fat metabolism is disturbed, which is a prerequisite to obesity and diabetes (Astrup 408). In recent years, diabetes has become more prevalent even among children. It is particularly alarming and makes the fight against the disease extremely important. It is necessary not only to improve methods of treatment, but normalize the food diet to regulate carbohydrate metabolism. It is important to unlearn the habit to eat a lot of sweets and cakes. Excess sugar in the food is not digested and not stored as glycogen in the liver; the excess of carbohydrates is converted into triglycerides, which leads to intensive development of adipose tissue. In response to the increased intake of carbohydrates, blood concentration of insulin increases, which activates the formation of fat from carbohydrates. Thus, excessive consumption of carbohydrate is one of the leading reasons of obesity caused by a violation of lipid metabolism (Mead et al. 607).
The body’s need for carbohydrates is expedient to meet by a slowly absorbed complex of carbohydrates such as starch. It is proposed to use fructose since it is almost 2 times sweeter than traditional sugar; thus, one can use it 2 times less. Fructose quickly leaves the blood; being utilized by organism cells, it is involved in the synthesis of cholesterol and fat to a lesser extent than sugar and normalizes blood sugar (Mokdad et al. 1199).
Thus, it should be noted that food is one of the most important environmental factors influencing health, mental and physical development, as well as duration of human life (Waxman 162). Stable mood, high mental and physical performance, full sleep, harmonious figure, and good skin are the result of proper nutrition. However, food in certain conditions can be harmful to the body. Knowledge of the mechanisms of adverse impact of food helps to prevent painful reactions. The challenge for medicine is to use food as a healing factor in various diseases of people. There are no universal recipes how to stay healthy for many years. However, one knows for sure that a healthy food diet helps to permanently maintain the level of health, which the person receives at birth.