Sixty to 75 percent of total body weight is water. Most people know that blood, lymph, urine, sweat and tears are mostly water. However, many do not realize that the lungs are 90 percent water, the brain is 76 percent and even bones are 25 percent water.

Sixty-seven percent of the water in the body is inside the cell (i.e., the intracellular fluid). The other 33 percent lies outside the cells in the extracellular fluid. The extracellular fluid includes the fluid surrounding the cells and the fluid in other compartments, such as the blood, lymph, spinal fluid and joint spaces.

Water has many functions in the body. It delivers nutrients to tissues and carries away unwanted wastes. It is the medium in which all chemical reactions take place within cells, and therefore greatly influences cell function. Water also serves as a cushion and lubricant for our spine and other joints.

Most individuals lose between 10 and 16 cups of water per day. This loss is in sweat, urine, feces, in the air we exhale, and via direct evaporation from our skin. During exercise in a warm climate, as much as 8 cups of water can be lost in one hour.

The loss of body water through urination is greatly increased by the ingestion of caffeinated and alcoholic beverages. These drinks have a diuretic effect, meaning they stimulate the kidneys to excrete more urine. Not only do we lose water, we also lose water-soluble vitamins, such as vitamin C, vitamin B1 (thiamine) and other B complex vitamins. There also is increased excretion of calcium, magnesium, potassium, sodium, chloride and zinc. (See sidebar on Page 36 for more information about the negative effects of caffeine.)

A diet containing lots of fruits and vegetables will supply about 4 cups of water per day. Even with a diet high in fruits and vegetables, it is still necessary to drink an additional 6 to 8 cups of water per day to supply enough water to meet the body's daily needs. For every caffeinated or alcoholic beverage you drink, you need to add an additional glass of pure water.

Insufficient water intake results in suboptimal intracellular water volume and reduced cell function. This greatly diminishes the body's ability to heal damaged tissues from injury and maintain optimal health. F. Batmanghelidj, M.D., author of Your Body's Many Cries For Water, has successfully treated many diagnosed diseases-peptic ulcers, colitis, hypertension, rheumatoid arthritis, chronic back and neck pain, anxiety, depression, chronic fatigue, high cholesterol, asthma, allergies and diabetes with simply increased and regular intake of water.

According to Dr. Batmanghelidj, dry mouth is the last sign of inadequate cellular water. When the thirst signals produced by the body are ignored or are responded to with intake of beverages other than water (i.e., soda, coffee, tea or concentrated fruit juice), eventually the body stops providing the sensation of thirst. It often requires drinking water regularly throughout the day for as long as six to eight months for the normal thirst signals to return, and for people to reacquire a taste for water. It can take up to a year or longer to rehydrate your tissues. The sensation of thirst also diminishes as we age. Therefore, it is very important for the elderly to acquire a "habit" of drinking adequate water to avoid cellular dehydration and subsequent health problems.

Water, Salt And Protein

Water does not work on its own. It needs help from both salt and protein. Salt and protein are like guardians; they move water to where it should be and keep it there. Without sodium (salt) in the body, the water you drink would never be absorbed, and drinking a glass of water would cause diarrhea. Basically, salt pulls water through the intestinal lining and into circulation. Once water is in circulation, proteins attract water in almost the same way that iron filings are attracted to a magnet. The attraction of water for the proteins in the blood maintains the blood volume and circulation. If there were no proteins in the blood, the water would flow right through the walls of arteries and veins and into the surrounding tissue. The blood volume would drop, and cells and tissues would not receive necessary nutrients and oxygen, and the cells would die. Insufficient salt and protein results in low blood volume and, therefore, very poor blood circulation. The most common symptoms are cold hands and feet, low blood pressure and dizziness when standing quickly from lying down or sitting.

Besides helping to control fluid volume in the body, sodium also is required for the absorption of many minerals and amino acids. Most people know that too much salt can be bad for you. Individuals who eat a lot of processed foods have high salt diets that can be detrimental. One reason is that excessive salt intake causes increased excretion of calcium in the urine. Of course, processed foods do not contain adequate calcium or other quality nutrients, so eating refined foods actually causes depletion of nutrients. However, if you are on a whole foods diet and do not eat a lot of refined or processed foods, you may need to add some salt to your food. Many health-conscious individuals are actually salt deficient. Recent research has even found a link between salt deficiency and chronic fatigue syndrome.

The quality of available salt is very variable. Salt in its natural form is 82 percent sodium and chloride and 18 percent other minerals. Most salt sold in the grocery store is processed, and therefore is almost 100 percent sodium and chloride. With the purpose of preventing iodine deficiencies, processed salt has iodine added. Adding iodine to sodium chloride crystals causes them to turn purple. Since purple salt is not common, the salt is bleached to turn it white again. Flow agents (chemicals) are added to reduce the absorption of moisture from the air to keep the salt flowing from your saltshaker. Most table salt is no longer in its natural form. It has had all the minerals except sodium and chloride removed; and it contains residues of the bleaching chemicals, along with the flow agents. Sea salt, frequently sold in health food stores, also may have had all the minerals except sodium and chloride removed. If a salt is very white and dry, it has had the additional minerals removed. In its natural form, salt is usually grayish, or off-white, and is moist. One of the best sources for natural salt is the Grain and Salt Society (1-800-TOP-SALT). The Celtic salt it sells is harvested from the Brittany area of France using methods that have been used for hundreds of years. The salt is gray and moist, and to most people has a much more pleasing taste than sea salt or processed salt.

Water Quality

The quality of water is just as important as the quantity. Regular consumption of water that has been contaminated with heavy metals or residues of chemicals will not promote good health.

Most tap water in municipalities comes from surface water, such as lakes and reservoirs, and it must be treated to filter out particulates and kill microorganisms. If the treatment system is working properly, the water also will be tested for 80 different compounds as dictated by Environmental Protection Agency (EPA) regulations. Unfortunately, there are several hundred thousand chemicals present in the environment from fertilizers, insecticides, pesticides, fungicides and other chemical and industrial wastes. Therefore, many pollutants in water are never identified.

The water treatment process itself leaves residues of chemicals such as chlorine in the water. Chlorine can react with organic compounds from broken-down vegetation to form trihalomethanes (THMs). THMs have been found to cause cancer in lab animals and are suspected of causing cancer in humans. Additional toxins can be added to water from the water pipes that deliver it to the faucet. Unhealthy levels of lead, copper and asbestos can enter the water from pipes. Some areas have natural bedrock formations containing high levels of radon. This radon can be found in water from these areas and causes increased radiation exposure, even through just washing dishes and bathing.

Occasionally, the water treatment process breaks down and microorganisms, such as giardia, cryptosporidium and E-coli, are not destroyed. A healthy individual will be able to fight off an infection from most water-borne microorganisms. However, when a child or an individual with a compromised immune system drinks this infested water, he or she easily can develop an illness that may even be life threatening.

Chemical residues, radon, microorganisms and naturally high levels of toxic minerals also can contaminate groundwater, the water source for most wells and springs. Groundwater can travel for miles deep beneath the surface, allowing contaminants to move from the initial site of exposure and pollute wells that are many miles away.

In the 1990s, the awareness of water quality problems prompted a tremendous increase in the sale of bottled water. What is not well known is that water bottling plants are governed by the Food and Drug Administration (FDA), not the EPA, and therefore are not governed by the same regulations. Water bottling plants only need to test for bacteria once a week and test only once a year for chemical contamination. They are not required to test for other microorganisms. Until recently, spring water could be taken from the same source as tap water.