Getting your "8 glasses of water" a day

The Food and Nutrition Board released the sixth in a series of reports presenting dietary reference values for the intake of nutrients by Americans and Canadians. This new report establishes nutrient recommendations on water, salt and potassium to maintain health and reduce chronic disease risk. Highlights of the report include:

◾The vast majority of healthy people adequately meet their daily hydration needs by letting thirst be their guide. The report did not specify exact requirements for water, but set general recommendations for women at approximately 2.7 liters (91 ounces) of total water -- from all beverages and foods -- each day, and men an average of approximately 3.7 liters (125 ounces daily) of total water. The panel did not set an upper level for water.

◾About 80 percent of people's total water intake comes from drinking water and beverages -- including caffeinated beverages -- and the other 20 percent is derived from food.

When we speak of water we are essentially focusing first and foremost on all types of water, be they soft or hard, spring or well, carbonated or distilled water. Furthermore we get water not only directly as a beverage but from food and to a very small extent also from oxidation of macronutrients (metabolic water). The proportion of water that comes from beverages and food varies with the proportion of fruits and vegetables in the diet. We present the ranges of water in various foods (Table 1). In the United States it is estimated that about 22% of water comes from our food intake while it would be much higher in European countries, particularly a country like Greece with its higher intake of fruits and vegetables or South Korea

Fluids come from the beverages you drink and the foods that you eat

Coffees and teas are not dehydrating. Limit caffeine intake to about 400 mg per day. That is equal to 750 mL (3 cups) of black coffee or 1 L (4 cups) of black tea per day.

Fact or fiction: Beverages that contain caffeine will contribute to your daily fluid
needs? FACT! Research has shown that beverages containing caffeine, such as
soft drinks, tea, and coffee can contribute to meeting your daily fluid needs as
much as non-caffeinated beverages, such as water, milk, and juice do. Some of
these beverages may contain calories, which should be accounted for in your diet.

Water comes from more than just fluids, it is a major component of many foods. In fact, it is estimated that 20% of our water needs are met through food, not fluids. Meal consumption is critical to ensure full hydration on a day to day basis. Eating food promotes fluid intake and retention.

Water comes from a variety of sources. All beverages or fluids are a source of water. Even solid foods contain water. Lettuce, celery, and other crisp vegetables are composed of 90 percent or more water. Protein-rich foods such as meat, fish, or chicken may contain as much as one-half to two-thirds their weight in water. Even grain products, which don’t seem watery at all, may be up to one-third water.

Fats, such as butter or margarine, and sugar are among the foods that contain the least water.

Some water, perhaps one to two cups per day, comes from inside our bodies as a byproduct of energy metabolism. This amount is small but significant.

It is important to be aware of fluid intake. Even though solid food is a source of water, additional water from drinking fluids is needed. Besides plain water, juices, milk, or other beverages boost fluid intake.