The human body can last weeks without food, but only days without water. The body is made up of approximately 55 to75 per cent water. Water forms the basis of blood, digestive juices, urine and perspiration and is contained in lean muscle, fat and bones.

As the body can't store water, we need fresh supplies every day to make up for losses from lungs, skin, urine and feces. Water is needed to maintain the health and integrity of every cell in the body, keep the bloodstream liquid enough to flow through blood vessels, help eliminate the by products of the body's metabolism, helps to flush out toxins, regulate body temperature through sweating, lubricate and cushion joints and carry nutrients and oxygen to the body's cells, just to name a few. Drinking refreshing, clean water plays a major role in reducing the risk of certain diseases.

The loss of body water through urination is greatly increased by the ingestion of decaffeinated 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 B (thiamine) and other B complex vitamins. For every caffeinated or alcoholic beverage you drink, you need to add an additional glass of pure water.

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. Dehydration occurs when the water content of the body is too low. This is easily fixed by increasing fluid intake. Symptoms of dehydration include headaches, lethargy, mood changes and slow responses, dry nasal passages, dry or cracked lips, dark-colored urine, weakness, tiredness, confusion and hallucinations. Eventually urination stops, the kidneys fail and the body can't remove toxic waste products. In extreme cases, this may result in death.

Approximately six to eight glasses of a variety of fluids can be consumed each day. More than eight glasses may be needed for physically active people, children, people in hot or humid environments, and breastfeeding women. Less water may be needed for sedentary people, older people, people in a cold environment or people who eat a lot of high water content foods.