Water is essential to life. The human body is made up of cells that are filled with water and need water to perform their day-to-day activities. Two-thirds of the human body is water. Your blood, which is responsible for carrying oxygen, nutrients, and waste products to and from cells, is more than 95% water. Water is even a major participant in many of the chemical reactions that take place in the body’s cells.

Water is the most often neglected nutrient. Yet, it is the one we can live the least time without. A person can survive only a few days without a water source, because humans need about a quart a day for cleaning out waste products. Waste products are created by metabolic body processes, such as breaking down food for use as energy. These waste products get into the bloodstream, where they are transported to the kidneys for filtering and removal through the urine. When water intake is lower than the amount needed for this waste management process, the kidneys work hard to concentrate the urine and re-absorb as much water as they can. The end result is that these waste products—some of them toxins—stay in the body longer than necessary.

Drink water to keep your body working smoothly and cleanly.

Another unhappy consequence of taking in too little water is dehydration and its associated symptoms such as dry mouth, dizziness, cramping, nausea, and confusion. Other problems with chronic lack of adequate fluid include increased risk of kidney stones, bladder infections, morning headaches, and—in women—vaginal infections and water retention. Because water is an important player in regulating body temperature (especially cooling through sweat), people who live in warm climates or do physical activity (which creates heat internally) need to drink more fluids than those who are inactive or living in cold places. In addition, the consumption of excess salt, diuretics (substances like caffeine, alcohol, and water pills), or excess protein increases the amount of water required by the body.

Does the Fluid Have to Be Water?

Under most circumstances, water is the best fluid to replace liquid lost due to waste management and sweating. We do, of course, get water from other sources such as fruits and vegetables. When trying to decide which fluids—other than water—are the most healthful, consider the following:

• Has care been used in the beverages’ preparation to retain nutritional value and minimize the addition of sugar and non-nutritive substances? Examples of beverages that do not meet this criterion include most sodas, most sport drinks, and diet soft drinks sweetened with artificial sweeteners. Although these types of beverages do contribute to water balance, they should be avoided because they are highly processed.
• Does the beverage contain caffeine or alcohol? Caffeine and alcohol are considered diuretics (substances that cause water loss) and fluids containing them leave the body quickly. For this reason, beer, coffee, tea, wine, colas, diet colas, hot chocolate, and all drinks containing hard liquor should not be counted in your total fluid intake for the day. These beverages do not contribute positively to water balance, and when consumed in large quantities may have other detrimental effects on health.
• While some fruit or veggie juices may be minimally processed, they still lack fiber and usually contain a high amount of sugar.

How Much Water or Other Healthful Fluid Is Enough?

A number of factors contribute to our water need. As a general guideline, most inactive people in an average climate need a minimum of six to eight cups per day. Add an additional two cups per pound lost due to sweat from heat or physical activity. A person who loses three pounds during a soccer game in the sun needs 6 (2×3) cups to make up the losses due to sweat, plus the six to eight cups needed for water balance, for a total of 12-14 cups for the day.

So remember, drink lots of water. It’s important for your health.

This article has been adapted from New Century Nutrition, a former health internet site and publication developed under the leadership of Dr. T. Colin Campbell.