ESSENTIAL NUTRIENTS AND BODY WATER

The six classes of nutrients found in foods are carbohydrates, lipids, proteins, vitamins, minerals, and water. Nutrients are classified as essential or nonessential. Nonessential nutrients are manufactured in the body and do not need to be obtained from food. Examples include cholesterol, a fatlike substance present in all animal cells. Essential nutrients must be obtained from food sources, because the body either does not produce them or produces them in amounts too small to maintain growth and health. Carbohydrates, lipids (mostly fats and oils), and proteins constitute the bulk of the diet, amounting together to about 500 grams per day in actual weight. These macronutrients provide raw materials for tissue building and maintenance as well as fuel to run the myriad of physiological and metabolic activities that sustain life. In contrast are the micronutrients, which are not themselves energy sources but facilitate metabolic processes throughout the body: vitamins, of which humans need about 300 milligrams per day in the diet, and minerals, of which about 20 grams per day are needed. The last nutrient category is water, which provides the medium in which all the body's metabolic processes occur. Water is undoubtedly the most common and most important of all chemical compounds. The properties of water have played a central role in the development of life on Earth and it is essential to all living organisms. Because of its prominence, water has further played an important religious and philosophical role in human history.

As I have earlier highlighted above, an individual needs varying amounts of each essential nutrient, depending upon such factors as gender and age. Specific health conditions, such as pregnancy, breast-feeding, illness, or drug use, make unusual demands on the body and increase its need for nutrients. Dietary guidelines, which take many of these factors into account, provide general guidance in meeting daily nutritional needs. However, we would like to emphasis more on body-water composition and requirement in this article.

If the importance of a nutrient is to be judged by how long we can do without it, water ranks as the most important. Although often overlooked as a nutrient, water (H2O) is actually the most critical nutrient of all. Water provides the medium in which nutrients and waste products are transported throughout the body and the myriad biochemical reactions of metabolism occur. Water allows for temperature regulation, the maintenance of blood pressure and blood volume, the structure of large molecules, and the rigidity of body tissues. It also acts as a solvent, a lubricant (as in joints), and a protective cushion (as inside the eyes and in spinal fluid and amniotic fluid). The flow of water in and out of cells is precisely controlled by shifting electrolyte concentrations on either side of the cell membrane. Potassium, magnesium, phosphate, and sulfate are primarily intracellular electrolytes; sodium and chloride are major extracellular ones. A person can survive only eight to ten days without water, whereas it takes weeks or even months to die from a lack of food. While water has no caloric value and therefore is not an energy source, without it in our diets we could not digest or absorb the foods we eat or eliminate the body's digestive waste.

The human body is 65 percent water and about 50 to 70 percent of body weight is water in approximately 60 percent of healthy adults and an even higher percentage in children. The human body consists of materials similar to those found in foods; however, the relative proportions differ, according to genetic dictates as well as to the unique life experience of the individual. The body of a healthy lean man is composed of roughly 62 percent water, 16 percent fat, 16 percent protein, 6 percent minerals, and less than 1 percent carbohydrate, along with very small amounts of vitamins and other miscellaneous substances. Females usually carry more fat (about 22 percent in a healthy lean woman) and slightly less of the other components than do males of comparable weight. Because lean tissue is about three-quarters water, and fatty tissue is only about one-fifth water, body compositionthe amount of fat in particulardetermines the percentage of body water. In general, men have more lean tissue than women, and therefore a higher percentage of their body weight is water.

It takes an average of eight to ten cups to replenish the water our bodies lose each day. How much water a person needs depends largely on the volume of urine and sweat lost daily, and water needs are increased if a person suffers from diarrhea or vomiting or undergoes heavy physical exercise. Water is replenished by drinking liquids, preferably those without caffeine or alcohol, both of which increase the output of urine and thus dehydrate the body. Many foods are also a good source of water like fruits and vegetables, for instance, are 80 to 95 percent water; meats are made up of 50 percent water; and grains, such as oats and rice, can have as much as 35 percent water. Water is sometimes consumed not only as water itself but as a constituent of other beverages or as a major component of many foods. Water also is manufactured in the body as an end product of metabolism. About 2.5 litres of water are turned over daily, with water excretion (primarily in urine, water vapour from lungs, sweat loss from skin, and feces) balancing intake from all sources. Because water requirements vary with climate, level of activity, dietary composition, and other factors, there is no one recommendation for daily water intake. However, adults typically need at least two litres (eight cups) of water a day, from all sources. Although most adults drink one to two litres of water a day, much of this is in the form of liquids such as coffee, tea, fruit juices, and soft drinks. In general, these are appreciated more for their taste or for their effects than for their nutritive value. Fruit juices are, of course, useful for their vitamin C content and are good sources of potassium. Coffee and tea by themselves are of no nutritive value, except that coffee contains some niacin and tea contains fluoride and manganese; these beverages also contain natural caffeine, which has a stimulating effect. Caffeine is added to colas, and so-called diet soft drinks contain small quantities of artificial sweeteners in place of sugars so that their overall calorie value is reduced.

Thirst is not reliable as a register for dehydration, which typically occurs before the body is prompted to replace fluid. Therefore, water intake is advised throughout the day, especially with increased sweat loss in hot climates or during vigorous physical activity, during illness, or in a dehydrating situation such as an airplane flight.

A nutrient is considered 'essential' if it must be taken in from outside the body in most cases like from food. Although they are separated into categories for purposes of discussion, one should keep in mind that nutrients work in collaboration with each other in the body, not as isolated entities. Amigos, if water was not an important nutrient in your diet we would not even waste your time enlightening you on this but because each and every person at the moment has immunity issues of which neglecting any of them is bringing detrimental consequences. Water is life and we want you to appreciate it as an essential product for your basic chemistry.

JONES. H. MUNANG'ANDU (author)
Motivational speaker, health commentator &
Health practitioner
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