Concept of Diet & Nutrition According To Modern Science
The basic need of our body is energy to move and to do work. Food is the main source to get energy. Westerners are concerned with the nutritive value of food that we consume and food items are analyzed on the basis of Protein, Carbohydrates, Fat, Vitamins and Minerals etc. Balanced diet is decided on the basis of these with food groups. Their intake is increased or decreased depending on the requirements and needs of the individual. But unfortunately no thought has been given to the sources of food, since no food item is prohibited to them. Prohibition is based only on requirements or non-requirement of certain food items. Therefore it can be safely stated that Western dieticians have focused their attention mainly on physical health through the food. Effects of food on the mind and behavior of individuals has been not given much importance while discussing on this subject.
- Carbohydrates:
Carbohydrate is probably the oldest subject in Western nutrition. It is the fuel on which body functions are based and in the 1800`s the study of nutrition was assumed to be the study of this fuel. Nutritional value was judged largely on the number of calories that a food could provide so that foods like tomato, which are low in calories, were considered to be of ‘little nutritional value.’ Though other items have been discovered, in terms of sheer quantity, carbohydrates remain the most important. If one leaves out water and fiber content of food, it is carbohydrate which makes up the bulk of diet. The average person eats ten ounces of carbohydrate for every ounce of protein. This huge amount of carbohydrate is used by the body for energy. It is on this energy that the entire metabolism depends. Without the burning or internal combustion of carbohydrates, the body’s primary source of energy would be missing. Just as the automobile runs on fuel, the body runs on carbohydrates. The carbohydrate, by contrast on which body cells function, is so called because it is a form of Carbon to which water has been added. Plants take Carbon dioxide from the atmosphere and water form the soil and, using the energy from sun light to force the two together, combine them to form the series of complex chains called rangers and starches. The combustion of carbohydrate by the body cell breaks the carbohydrate molecule back down to its original components, Carbon dioxide and water. The water is exhaled in the breath and excreted in the urine, the Carbon dioxide is exhaled and returns to atmosphere. In the animal cell the oxygen is used to burn Carbohydrate. Thus, there is a constant recurring cycle.
There are various types of sugar molecules. A few contain five Carbon atoms, but most contain six. They attach to each other. Wheat contains carbohydrate in large quantities. Other items which have Carbohydrate include rice, corn, millet, buckwheat, rye, oats etc. Wheat contains 72% Carbohydrates, 1.7% Fat. It contains minerals in the form of Iron (1.6%) and Calcium 20mg per 100gm.
Rye is a cereal closely related to wheat.
Rice provides about 350 Kcal per 100g dry weight.
Rice contains 7% Protein; Rice contains Vitamins B, mainly thiamine.
Corn contains 2.1g Protein, 0.1gFat, 21.0g Carbohydrate and 95 Kcal in 25g flour.
- Protein:
Protein is a structural material which provides the rigid structures which enable plants and animals to raise themselves above the surface of earth. The word protein is Greek word meaning first or holding first place. Protein contains Nitrogen but the nutritive value of Protein-rich foods does not depend upon the total Nitrogen contents but on the constituent amino-acids. Gelatin for example is rich in Nitrogen but does not contain all the essential amino-acids and so is of little nutritive value. Proteins constitute about 15% of body weight. The liquid part of blood contains over hundred different proteins, each with a specific function. The other elements always present in proteins are carbon, hydrogen, oxygen, sulphur, phosphorus, iron, copper and zinc. Protein known as immuno-globulin serves as the first line of defense against bacterial and viral infections. Biochemical catalysts known as enzymes are Proteins. Several hormones are Protein in nature. Structural proteins furnish mechanical support and some of them like action and myosin are contractile proteins and help in the movement of muscle fibers, microvillus etc. Some proteins preset in cell membrane, cytoplasm and muscle of the cell as receptors. The transport Proteins carryout the function of transporting specific substances in either the membrane or in the body fluids. Storage Proteins bind with specific substances and store them, for example Iron is stored as fertile under certain conditions Proteins can be categorized as supplies energy. When Protein is mentioned in the highly industrialized countries of the West, most of they think that protein comes from meat, flesh, and fowl. Although meat, cheese, milk and eggs are usually considered as “the protein foods,” There are many other important sources of Protein. Beans, peas, nuts, leaves and legumes (especially when combined with grains) also contain a high percentage of Protein.
How much Protein should we take?
As the result of popular books on nutrition many people have the idea that with Protein, there is no limit `the more the better`. This is wrong. This was in fact, proved in experiments at MIT where 100 young men were given experimental diets which allowed regulation of Protein intake. Generally an amount less then 30g (one ounce) was sufficient. Thus recent official figures from the National Research Council are 70g for adult men and 60g for a woman and for an average person, 50g is adequate. One should maintain Protein level in the body; otherwise he or she has to face many problems. Whole food, beans, grain, fruits and vegetables all contain a complex of nutrients.
- Vitamins
Vitamins have been defined as organic compounds occurring in natural food either as such or as utilizable ‘precursors’ which are required in minute amounts for normal growth, maintenance and reproduction, for normal nutrition and health. Carbohydrate, fat, and protein are the bulk of man’s diet. In 1906, Sir Fredrik Hopkins published an article which proposed that besides these basic elements small quantities of some unknown ‘ accessory nutrients’ must also be required for the maintenance of good health. Six years later in, 1912, one of these, the substance that could prevent beriberi (a disease) was isolated from rice polish by a Polish chemist. Since it was vital for the preservation life and was an amine (Amino-acid like substance) it was called Vitamin. Vitamins are basically divided in following categories:
- Vitamin A:
In general, the term Vitamin A is used when reference is actually made to more than one vitamin. Vitamin A sources are following:
- liver oil
- butter
- milk
- cheese
- egg yolk
- carrots
- Green-yellow vegetables
- Spinach
- and fruits such as mangoes, papayas, corn, sweet, potato.
Lack of vitamin A can cause night blindness.
Vitamin B:
The water extracted from rice polishing which had the power to reverse beriberi, began to be called Vitamin B. Up to now twenty five B’s Vitamins have been found. The term B /-complex continues to be used to denote a large number of heavy Varieties. Those foods which are rich in only one member of the B vitamin are rare. The main sources of Vitamin B are germ and bran of seeds such as cereals, nuts, beans, peas etc. Besides these sources, meat, eggs and liver are other sources of Vitamin B complex.
Vitamin C:
One constituent of the citrus juice, ascorbic acid, identified in 1928, was found to be extremely powerful in preventing scurvy. It was soon called Vitamin C. It was felt that the absence or deficient Vitamin C had impaired the formation of collagen (the fibrous connective tissue that is so important in the repair and healing of wounds). It is officially estimated that the minimum daily requirement of Vitamin-C is about 45mg. Besides citrus fruits, green leafy vegetables, lemon, orange, amla are rich in Vitamin-C. Milk contains a small amount of Vitamin-C. Even tomato squash and potato are rather good sources of Vitamin-C.
Vitamin-D:
Vitamin D is not obtained in significant quantities from food. For the most part, one depends upon, manufacturing his own Vitamin D through the action of sunlight on certain oil-like substances in the skin which are related to Cholesterol. The fact is that the substance which we call Vitamin-D is unique and differs from other Vitamins in a number of ways. If a large amount of Vitamin-D is taken suddenly, there will be nausea, vomiting, diarrhoea, dizziness and weakness. The main sources of Vitamin-D are sunlight, milk, butter, eggs and fish oil etc.
Vitamin-E:
Probably the most controversial Vitamin, with the possible exception of Vitamin C, is Vitamin-E. It has not even been universally accepted that Vitamin-E is a necessary nutrient for man and yet it is taken in large doses by millions of people for an extraordinary array of human ailments. An experiment done in America on rat’s diet. It was found that male rats became sterile. Over the years Vitamin-E has tended to lose this image, and is now firmly fixed in the mind of public as a valuable measure for treating heart diseases. Main sources of Vitamin-E in diet are wheat, green vegetables, peas, corn, etc.
Other Vitamins:
Vitamin K is normally manufactured in the intestinal tract by certain bacteria. It is found in green plants and green leafy vegetables. A small dose of naturally accruing Vitamin K sometimes reduces the nausea in pregnancy. Vitamin F was a term once use for ‘essential fatty acids’. They are contained in vegetable oil, grains, seeds, nuts and vegetables. Vitamin F supplements have apparently helped some cases of prostate diseases.
- Minerals:
When plant or animal tissue is burnt, the Nitrogen, Sulphur, Hydrogen and Carbon that make up the fats, carbohydrate and protein go off as gases, and the minerals alone remain as ash. The minerals that will be found through such a process to be in the body are primarily sodium, potassium, calcium, phosphors and magnesium. But there are also a number of other minerals found in very tiny and trace amounts such as Zinc, Iodine, Manganese, Copper and even Arsenic. They are often the key ingredient in the large protein molecules we call Enzymes, on whose action most of the metabolic process of the body depend. The list continues to grow as with increasingly sophisticated technology we have discovered that Minerals which we had considered only accidentally present in tissues actually play important in metabolic roles .