Why is drinking water important?

Around 60 percent of the body is made up of water, and around 71 percent of the planet's surface is covered by water.

Perhaps it is the ubiquitous nature of water that means drinking enough each day is not at the top of many people's lists of priorities.

Fast facts on drinking water

• Adult humans are 60 percent water, and our blood is 90 percent water.

• There is no universally agreed quantity of water that must be consumed daily.

• Water is essential for the kidneys to function.

• When dehydrated, the skin can become more vulnerable to skin disorders and wrinkling.

• Drinking water instead of soda can help with weight loss.

• In a CDC questionnaire, 7 percent of respondents reported drinking no water at all daily.

Benefits

To function properly, all the cells and organs of the body need water.

It is also needed to:

• lubricate the joints

• form saliva

• deliver oxygen throughout the body

• cushion the brain, spinal cord, and other sensitive tissues

• regulate body temperature

• produce hormones and neurotransmitters

• help food pass through the intestines

• flush body waste

Some of the water required by the body is obtained through foods with a high water content, such as soups, tomatoes, oranges, but most come through drinking water and other beverages.

During everyday functioning, water is lost by the body, and this needs to be replaced. We notice that we lose water through activities such as sweating and urination, but water is lost even when breathing.

Drinking water, whether from the tap or a bottle, is the best source of fluid for the body.

Milk and juices are also good sources of fluid, but beverages containing alcohol and caffeine, such as soft drinks, coffee, and beer, are not ideal because they often contain empty calories. Drinking water instead of soda can help with weight loss.

It was previously thought that caffeinated beverages had diuretic properties, meaning that they cause the body to release water. However, studies show that fluid loss because of caffeinated drinks is minimal.

Do we drink enough water?

A study carried out by the Centers for Disease Control and Prevention (CDC) in 2013 analyzed data from the National Cancer Institute's 2007 Food Attitudes and Behaviors Survey.

Out of a sample of 3,397 adults, the researchers found:

• 7 percent of adults reported no daily consumption of drinking water

• 36 percent of adults reported drinking 1-3 cups of drinking water a day

• 35 percent of adults reported drinking 4-7 cups of drinking water a day

• 22 percent of adults reported drinking 8 cups or more a day

People were more likely to drink less than 4 cups of drinking water daily if they consumed 1 cup or less of fruits or vegetables a day.

The study only measured the intake of drinking water. While fluid can be gained from other beverages, water is the ideal source of fluid because it is calorie-free, caffeine-free, and alcohol-free.

Seven percent of respondents reported drinking no water at all daily, and those who drank a low volume of water also consumed less fruit and vegetables. This suggests that a certain number of people are risking their health by not getting enough fluid.

Even if the respondents reporting low levels of water intake were obtaining enough fluid, it is likely that they would be obtaining it from sources that could potentially compromise their health in other ways.

"The biologic requirement for water may be met with plain water or via foods and other beverages," write the study authors. "Results from previous epidemiologic studies indicate that water intake may be inversely related to volume of calorically sweetened beverages and other fluid intake."