One of the major contributory factor to high blood pressure is obesity. To remedy this condition it is essential to reduce weight. And to reduce weight scientifically it is essential to understand the value of balanced diet. Hence, we have included in this chapter, a discussion on the basis of Nutrition including essential ingredients required for normal good health. Finally, we have made suggestions by which you can select a well balanced diet for yourself to enable you to reduce weight scientifically without any danger to your health.
Nutrition is a subject that should interest every human being because nutrition is concerned with the building and maintaining good health. It has been shown by research that many diseases that are caused by deficiencies in a diet, can often be corrected when nutrition is improved and the deficiency is removed. Conversely, it is also true that excessive intake of particular ingredients in a diet also leads to health hazards. It is important to emphasise that what we eat is as important as how much we eat. These two factors together, ultimately decide the conditions of our body and mind. When a person ejoys good health, there is a sense of physical and mental well-being. There is a tremendous feeling of energy, fitness, strength and mental awareness. To eat wisely, therefore, is the first step towards good health. It is proposed in this chapter, to briefly describe and explain all the factors that go to form what we term “nutrition”. At the same time, a few menus and recipes have been suggested for those interested in weight reduction as a means of removing certain risk-factors.
Food Constituents and Their Functions:
We all know that a certain amount of food is necessary for all of us. Food provides the raw materials that are required for building up our body as well as for the maintenance and repair of the tissues in our body. Food is also essential as it provides the source of energy or fuel in our body. There are three major constituents that food is composed of, namely,
- Fats and
- Mineral elements
- Water and
- Dietary fibre
Proteins are complex organic compounds containing mainly elements such as carbon, hydrogen, oxygen and nitrogen. Proteins can be broken down by enzymes into smaller units called amino-acids which are really the basic building blocks of our bodies. Proteins form the major constituents of muscles and other tissues and of vital fluids like blood. Thus the proteins in our food actually provide in raw materials required for cell growth. There are about two dozen different amino-acids and many of these can be synthesized by the human body itself. But a few of these amino-acids cannot be made by the body and these are therefore called essential amino acids.
The essential amino-acids, must be present in the food we eat if we are to enjoy good health and well-being. All the essential amino acids are usually present in what we call the ‘animal protein foods’ such as mutton, beef, fish, chicken eggs, pork etc. Very often the ‘vegetable protein foods’ are deficient in atleast one essential amino-acid and are therefore incomplete proteins on their own. However, a combination of selected vegetables can often provide all the amino-acids required by the body. The best way to ensure adequate protein intake however, would be to mix animal and vegetable proteins in one’s diet. This is important because our bodies cannot store dietary proteins or amino-acids as it stores carbohydrates and fats. Since proteins are mainly important for tissue growth and repair, children need more protein than adults.
When there is a protein imbalance in the diet or the diet lacking some of the essential amino-acids, there is excessive production of uric acid in the body. Uric acid accumulation leads to gout and other unpleasant conditions. It is also well known that protein deficiency or constant intake of low-value protein leads to deficiency diseases such as Kwarshirokar etc.
Fats are chemical compounds formed from carbon, hydrogen and oxygen. Fats can be either solid fats, or oils which are liquid at room temperature. Solid fats usually come from vegetable sources e.g., groundnut, coconut, olive, sunflower, safflower and corn oils. Fats have an important role to play in our body. They provide a concentrated source of energy in the body. They also provide a layer of insulation in the body so that the body remains heat and keeps out the cold. Finally, fats also furnish protection for the vital organs of the body such as the kidneys and eyes. Fats are broken down by our bodies into smaller molecules called fatty acids, which are then absorbed and stored by the body. Whenever the body requires energy, the fatty acids are ‘oxidized’ to give their basic constituents carbon-dioxide and water with the release of heat and energy.
Fats are of two types- saturated and unsaturated. These terms refer to the position of the hydrogen atoms in the fatty acids. When all the chemical bonds between the carbon atoms are occupied by hydrogen atoms called saturated fats. Fats that are solid are predominantly saturated e.g., hydrogenated cooking fats, margarine, butter, tallow etc. In the fatty acids of unsaturated fats or oils, all the chemical bonds are not occupied by hydrogen atoms called unsaturated fats.
Essential Fatty Acids
Three fatty acids, linoleic, linolenic and arachidonic are called ‘essential fatty acids’ because they are required in the body before cholesterol and saturated fatty acids can be utilized. These are usually obtained from vegetable oils such as groundnut, safflower, sunflower seed and soya oils. The essential fatty acids are important because they facilitate the breakdown of saturated fats and cholesterol in the body and thus prevent their deposition in the arteries.
Carbohydrates are mainly found in sugars and starches but also occur in cereals and many other foods. They are primarily, an energy source for the body. Our digestive juices breakdown the carbohydrates to simple sugars which are then converted by the liver into glucose. And glucose as we all known is the best and most basic source of energy for the body.
When a person’s diet contains more carbohydrates than required by the body, glucose is stored as glycogen in the muscles and liver. When a person consistently eats food rich in carbohydrates, the glycogen in his body is converted to fat. On the other hand if a person eats a diet which is deficient in normal carbohydrate intake, then the body’s energy requirements are met by the utilization of body proteins. However, our bodies will preferentially utilize carbohydrates for energy rather than proteins, in order to ‘conserve’ proteins for their all important function of growth and tissue repair.
It is now history, how the importance of vitamins was discovered early in this century. Results from the examination of hundreds of victims of diseases such as Scurvy, Beri-Beri, Rickets and Pellagra indicated that they all shared some nutritional deficiency that impaired normal metabolism. Scientists concluded from this that apart from Proteins, Fats and Carbohydrates a fourth ingredient, as yet unknown, had to be present in food for proper growth and health. These micronutrients were given the name ‘Vitamins’.
Vitamins are all organic compounds which cannot be synthesized in our bodies. They occur naturally in foods and are required in minute amounts in our diet as they regulate certain chemical processes during metabolism. Their absence in the body could lead to disease, poor health and sometimes even death. Today, about sixteen different vitamins are known and they have varied functions at different levels in the body. Everyone of us has a basic daily requirement for these vitamins which we normally obtain from our food. Any vitamins in excess of our normal requirements are superfluous and are usually excreted out by the body.
Mineral Elements are nutrients which are found in foods and which are essential to the body in microscopic amounts. These trace elements are mostly metals such as calcium, nickel, iron, aluminium, zinc, sulphur, iodine, copper, magnesium, phosphorous, etc. They have specialised functions that are necessary for the optimum working of the body. For example, calcium, magnesium and phosphorous are required for forming strong bones and teeth. Iron is necessary for the formation of haemoglobin i.e. the red pigment of the RBCs which carry oxygen to and from the heart. Iodine is important for the proper functioning of the thyroid gland. Fluorine is thought to be necessary for preventing tooth decay and so on.
water is one of the most important constituent of our diet and it makes up about 70% of our body’s weight. Even a 10% loss of water from the body can cause dehydration and death. Water is essential to our body because it is the substrate in which all the chemical and biochemical processes in our body take place. For example, water is necessary to keep the body fluid and flowing in the body. It enables the blood to carry nutrients to all parts of the body and to remove waste from the same.
It also helps to maintain body temperature i.e. when the body temperature rises, evaporation of sweat helps to cool down the body. Fortunately, nearly all food, even the apparently dry foods contain a sizeable amount of water. Therefore, water depletion under normal conditions rarely occurs except in certain cases such as severe diarrhoea, dysentery, vomiting or cholera.
It is also called roughage. It is the part of food that cannot be digested but is absorbed to produce energy. Food with a high fibre content include whole meal cereals and flour, root vegetables, nuts and fruits. Dietary fibre is considered to be helpful in the prevention of many of the diseases much as constipation, appendicitis, obesity, diabetes mellitus and heart conditions. Communities consuming high fibre diets may have less chances of any of these diseases.
Adverse Effects of Some Constituents of Food:
We have just seen the important role of some of the constituents play in our body for the maintenance of good health. Some of these constituents however, when consumed in an improper or poorly balanced diet can bring about adverse conditions which are damaging to the physical system. A few such adverse effects are explained below.
Fats cause damage to the body because they raise the level of cholesterol and uric acid which are factors contributing to artherosclerosis and gout. Fats also obstruct carbohydrate metabolism to some extent and are indirectly responsible for diabetes. When there is excess fat in the blood, the body does not make use of the sugar available and this can then show as excess sugar in the urine. If, at the same time, sugar intake is also in excess, then that person is certainly at risk for diabetes.
cholesterol is a fatty substance which is present in everyone’s blood. All tissues can synthesize cholesterol but only the cholesterol produced in the liver reaches the blood.
Cholesterol is utilized in various way by the body and any excess cholesterol is deposited on the inner lining of our arteries. This deposition in the arteries leads to narrowing and eventually even blockage of the arteries. Many other factors are also involved in the deposition of cholesterol and therefore in the last decade or so there has been a debate as to the direct role of cholesterol in causing high blood pressure and other heart diseases.
Sodium and Potassium in the Diet:
It has been shown by some medical scientists that high blood pressure can be produced in animals simply by feeding them excessive amounts of salt in the diet. Scientists and doctors know that the sodium part of common salt tends to hold water in body fluids and tissues. In excessive salt diets, the body retains so much water that the blood volume is increased and blood pressure is elevated. Decreasing the salt intake in a diet is an age-old method of reducing blood pressure and has been used with good effect before the advent of drug therapy for hypertension.