Water - How important is it?

Water is the most important nutrient throughout the living world. Humans in particular, cannot live without it for more than about 100 hours, whereas other nutrients may be neglected for weeks or months. Although commonly treated rather trivially, no other nutrient is more essential or is as needed in such great amounts as water.

The water content of our bodies varies with age and gender. As we grow, our body water content reduces. For example the unborn baby's body is made up of 90% water while that of a child is 60%. Adults have 59%(males) and 50(females – because of a higher fat content of their bodies).

A significant fraction of the human body is water. Lean muscle tissue contains about 75% water by weight. Blood contains 95% water, body fat contains 14% water and bone has 22% water.

Water is important to the mechanics of the human body. The body cannot work without it, just as a car cannot run without gas and oil. In fact, all the cell and organ functions made up in our entire anatomy and physiology depend on water for their functioning.

Water serves as a media for the all biochemical reactions that go on in the cells of our bodies. It acts as a solvent and separating medium, to carry and distribute nutrients, metabolites, hormones and other materials around the body and within cells. This means without water the cells which are the building blocks cannot function and the body as a whole will die.

Water is also used to remove metabolic waste products from our bodies, mainly via the urine and faeces. Metabolic wastes can become toxic to the body if they are allowed to accumulate. People with serious kidney disease may die of this if they do not have dialysis or a kidney transplant because of the accumulation of wastes.

The body also uses water to cool itself. Sweat produced when the body is hot is mostly water. As the water in the sweat evaporates, heat is taken away from the body and that cools the body.

Water serves as a lubricant between bodily structures. The joints have collections of fluid within them that makes the movement of the joints smooth and prevent early wear and tear of the joints. The brain is also covered by a type of bodily fluid called cerebrospinal fluid. This is mostly water and it serves as a form of shock absorber for the brain.

Water forms the base for saliva and all the other enzymes needed for digestion and absorption of food.

Water helps to alleviate constipation by softening food and stool to enhance movement through the intestinal tract.

The normal body water content or hydration is maintained by a good balance between the water input and water output. Water input include drinks (1500 mls), food(700 mls) and as metabolic by-product (300 mls). Water is also lost thorough urine (1500 mls), faeces (100 mls) skin and sweat (500 mls) and breathing (400 mls).

When there is a decrease in the body total water, it is called dehydration which can be due to a reduced intake with normal output or an increased output with a normal intake or both scenarios.

Dehydration (starting at about 2-3% loss of body weight) causes a range of symptoms from tiredness, headaches and decreased alertness to collapse and death (at more than 10% loss of body weight). Mild symptoms may be seen in the lack of concentration of schoolchildren towards the end of their school day, with improved concentration in those less thirsty.

Severe symptoms of dehydration are sometimes evident in the elderly, due to restricted water intake for medical, psychological or social reasons. Increased water intake is normally easily controlled due to the effective functioning of the kidneys to produce more urine. If this does not occur, due to greatly excessive water intake (for example if one drinks more than 1 litre of water per hour) or kidney disorder then the extra water (hyperhydration) may produce low blood sodium levels by dilution and cause the brain to swell, resulting in death from water intoxication.

The amount of water one needs to drink in a day actually depends on the age, sex, level of activity and the temperature and humidity of the environment. The experts have always said, on average, that eight eight-ounce glasses per day will suffice or 1.5 litres or more for the average adult.

Thirst is not a good indicator of dehydration because one needs to be dehydrated to a certain degree to feel thirst. This means if you are thirsty you need to drink twice the amount of water that satisfies you.

The colour of your urine can also tell you that you need to drink. If your body water is ok, your urine will be clear transparent to light yellow or amber. But if it is deep yellow then you are dehydrated so your kidneys are concentrating you urine to conserve water for your body.

A cold soda may feel nice going down, but beverages with caffeine are not meant to hydrate. Water is the best remedy for dehydration. If mild dehydration sets in, it can decrease one's energy level and mental functioning and increase stress on the body. Severe dehydration can have far more damaging effects.

Drink frequently throughout the day to prevent dehydration.

While some fruit juices and green tea may account for some fluid intake, you can count out beverages such as coffee or alcohol. They have a mild diuretic effect, which promotes urination and therefore water loss, which ultimately defeats the purpose.

A trick to ensure people are drinking their daily allowance is to fill a pitcher or jug with the allotment of water and keep it on your desk at work, or handy at home. The goal is then clearly marked. As you drink down the water, you know that you are on the right path to drinking enough water.