Water is a combination of hydrogen and oxygen. It is the basis for the fluids of the body.
Water makes up more than two-thirds of the weight of the human body. Without water, humans would die in a few days. All the cells and organs need water to function.
Water serves as a lubricant. It makes up saliva and the fluids surrounding the joints. Water regulates the body temperature through perspiration. It also helps prevent and relieve constipation by moving food through the intestines.
You get some of the water in your body through the foods you eat. Some of the water is made during the process of metabolism.
You also get water through liquid foods and beverages, such as soup, milk, tea, coffee, soda, drinking water, and juices. Alcohol is not a good source of water because it is a diuretic. It causes the body to release water.
If you do not get enough water each day, the body fluids will be out of balance, causing dehydration. When dehydration is severe, it can be life-threatening.
The Dietary Reference Intake for water is between 91 to 125 fluid ounces (2.7 to 3.7 liters) of water per day for adults. Keep in mind that this is the total amount you get from both food and beverages every day. There is no specific recommendation for how much water you should drink. If you drink fluids when you feel thirsty and have beverages with meals, you should get enough water to keep you hydrated.
Diet - water; H2O
Bistrian B. Nutritional assessment. In: Goldman L, Ausiello D, eds. Goldman's Cecil Medicine. 24th ed. Philadelphia, PA: Elsevier Saunders; 2011:chap 221.
Institute of Medicine. Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. 2005. http://www.iom.edu/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx.Accessed April 14, 2015.Institute of Medicine. Dietary reference intakes for water, potassium, sodium, chloride, and sulfate. 2005. http://www.iom.edu/Activities/Nutrition/SummaryDRIs/DRI-Tables.aspx. Accessed April 14, 2015.
Wolf R, Wolf D, Rudikoff D, Parish LC. Nutrition and water: drinking eight glasses of water a day ensures proper skin hydration - myth or reality? Clin Dermatol. 2010;28:380-383.
Update Date 8/19/2013
Updated by: Linda J. Vorvick, MD, Medical Director and Director of Didactic Curriculum, MEDEX Northwest Division of Physician Assistant Studies, Department of Family Medicine, UW Medicine, School of Medicine, University of Washington, Seattle, WA. Editorial update: 04/14/15. Also reviewed by David Zieve, MD, MHA, Isla Ogilvie, PhD, and the A.D.A.M. Editorial team.