This Facts About reviews water and provides a guide for selecting appropriate portion sizes and recommendations for incorporating healthy changes into your diet.

What are the recommended servings of water per day?

Although the data regarding optimal water intake is unclear, as a guide to ensure adequate hydration under normal circumstances, we recommend:

• Women: Drink 8 cups (64 oz./approx. 2 liters) per day
• Men: Drink 12 cups (96 oz./approx. 3 liters) per day

The vast majority of healthy people adequately meet their daily hydration needs by letting thirst be their guide.

Why should you drink water?

• It is an essential nutrient and makes up > 60% of adult body weight
• It is needed for all body functions, such as nutrient digestion, absorption, transport, and metabolism
• It aids in body-temperature maintenance
• It is vital to electrolyte balance
• Water contains no calories or fat
• May help with weight loss by acting as a natural appetite suppressant
• Prevents complications from dehydration, such as headache or fatigue
• May benefit people with respiratory diseases by thinning mucous secretions that worsen asthma
• May help people who experience recurrent urinary tract infections by increasing their urine flow
• May help reduce cancer risk of the colon, kidneys, bladder

How much water do you need?

The equivalent of 8 cups of water for women and 12 cups of water for men is the minimum amount of fluid recommended daily to replace water losses under conditions of moderate activity, mild temperature, and altitude.

Fluid requirements increase due to exercise, environmental factors, fever, pregnancy, and other conditions.

Dietary Sources

• Your diet provides the water your body needs. In an average adult diet, food provides about 20 percent of total water intake. The remaining 80 percent comes from beverages you drink.
• Beverage requirements are met best by consuming plain water. You can also choose herbal or green tea (hot or iced), diluted fruit juice, sparkling water, or add lemon/lime juice to plain water.
• Fruits and vegetables contain lots of water and are also good sources of vitamins, minerals and fiber.  However, your daily water requirement of 8 glasses for women and 12 for men should be consumed above and beyond the water that is consumed as food.
• While alcoholic beverages (like beer or wine) and caffeinated beverages (like coffee and colas) can contribute to your total fluid intake, they also have diuretic properties which can cause you to urinate more often and dehydrate more easily.

Specific Considerations

Dehydration

Too little water can lead to dehydration, a condition that occurs when you do not have enough water in your body to carry out normal functions. Even mild dehydration can make you tired. Signs and symptoms of dehydration include:

• Excessive thirst
• Fatigue
• Headache
• Dry mouth
• Little or no urination
• Muscle weakness
• Dizziness
• Lightheadedness

Drinking Too Much Water

• Drinking too much water is uncommon but may lead to hyponatremia, a condition in which excess water intake dilutes the normal amount of sodium in the blood
• Symptoms of water intoxication include nausea, vomiting, fatigue, and confusion
• Check with your doctor or a registered dietitian if you're concerned about drinking too much or too little water

Chlorine and Lead

Chlorine and lead are the two most common contaminants in tap and some bottled water. Although it may serve an important role in a public water supply, chlorine is a strong oxidizing agent and may increase the risk of heart disease and certain cancers. Small amounts of lead may be toxic, especially in infants, children, and pregnant women. The following are some ideas to increase the likelihood that your drinking water is safe:

• Use a quality bottled water
• If bottled water is too expensive for regular use, get into the habit of flushing your kitchen faucet daily by letting water run for about three minutes
• Have tap water tested to see if impurities exist
• State and local health departments often do free tests for bacterial contamination
• To find out about toxic substances, such as lead, arsenic, and high levels of chlorine, use a private testing lab
• A home purifying/filter system can help
• A home water distillation system may produce the purest water

Ideas to Increase Water Consumption

1. Keep a pitcher of herbal iced tea in the fridge.
2. Add fresh lemon or lime to juice to water.
3. Drink hot herbal tea.
4. We do not recommend drinking sodas because they are void of essential nutrients.
5. We do not recommend drinking juices because they are high in calories and usually lack the fiber of whole fruit.
6. Drink a glass of water with each meal and between each meal.
7. Take water breaks instead of coffee breaks.
8. Substitute sparkling water for alcoholic drinks at social gatherings.
9. Carry water in your car.
10. Keep a water bottle with you and drink throughout the day.  To keep a reusable bottle clean, wash it in hot, soapy water or run it through the dishwasher before refilling it.

These factors suggest you may be consuming enough water every day:

• You drink enough water to quench your thirst
• You produce a colorless or slightly yellow, normal amount of urine
• You fell well

This Facts About document is published by Monica Myklebust, MD, and Jenna Wunder, MPH, RD, at University of Michigan Integrative Medicine Clinical Services. Our mission is to care for people using an Integrative Medicine model that reaffirms the importance of relationship between practitioner and patient, focuses on the whole person, is informed by evidence, and makes use of all appropriate therapeutic approaches to achieve optimal health and healing.

Resources

Dietary Intake for Water, Salt, and Potassium
National Academies website 
http://national-academies.org
Accessed February 10, 2006.

Hydration Through the Seasons
American Dietetics Association website
www.eatright.org/
Accessed February 10, 2006

Nutrition Fact Sheet: Water
Northwestern University website
www.feinberg.northwestern.edu/nutrition/factsheets/water.html
Accessed September 23, 2004

Soda:  Does it Increase the Risk of Osteoporosis?
Mayo Clinic website
www.mayoclinic.com
Accessed March 10, 2006

Water: The Drink of Life
American Dietetics Association website
www.eatright.org/
Accessed February 10, 2006

Water: How much should you drink every day?
Mayo Clinic website
www.mayoclinic.com/health/water/NU002833
Accessed February 10, 2006

Water, Water Everywhere.  How Much Should You Drink?
American Dietetics Association website
www.eatright.org/
Accessed February 10, 2006

Why You Should Drink More Water
University of Iowa Health Care website
www.uihealthcare.com 
Accessed February 10, 2006

 The Wildcat Way to Wellness:  Water is the Liquid of Life
University of Kentucky Cooperative Extension Service website 
www.ca.uky.edu 
Accessed February 10, 2006

Original Research and Review Articles:

Altieri A, et al.  Fluid intake and risk of bladder and other cancers.  European Journal of Clinical Nutrition.  2003;57(Suppl 2):S59 -S68.

Chalupka S.  Tainted Water on Tap:  What to tell patients about preventing illness from drinking water.  The American Journal of Nursing.  2005;105(11):40 -52.

Gray M, et al.  Does fluid intake influence the risk for urinary incontinence, urinary tract infection and bladder cancer?  Journal of Wound, Ostomy, and Continence Nursing.  2003;30(3):126 -131.

Lin M, et al.  Disorders of water imbalance.  Emergency Medicine Clinics of North America.  2005; 23(3):749-70.

Manz, F, et al.  The importance of good hydration for the prevention of chronic diseases.  Nutrition Reviews. 2005;63(6):S2 -S5.