Dr. Water

Dear R. Sanders:

Recent media reports have drawn attention to the lack of research on how much water should be consumed for health promotion and disease prevention. Many scientists and major health organizations would agree; while it is clear that consuming adequate amounts of fluid is important for preventing dehydration, it is less certain exactly how much water is needed for optimal health.

The Institute of Medicine acknowledged this limitation and could therefore only establish an Adequate Intake (AI) for total water consumption (IOM, 2005). The AI for total beverages is ~9 and 13 cups per day for adult women and men, respectively. However, research suggests that most adults in our population only consume ~8 cups of total water (from foods and beverages) per day (Fulgoni, 2007). Of this amount, most US adults only consume ~ 5-6 cups of water per day as a beverage (Fulgoni, 2007; Popkin, 2006), which is far less than the commonly cited recommendation of 8 cups per day.

There is emerging research that maintaining adequate hydration is associated with improved cognitive function (Suhr, 2008), and that drinking water may help to control food intake at a meal (Dennis, 2008). In light of the increasing prevalence of obesity, it has also been suggested that our beverage consumption consist primarily on non-caloric beverages, ideally water. This may be supported by two findings: regular soft drinks are the #1 source of calories in the diets of Americans (Block, 2004), and replacement of sweetened beverages in the diet with water results in ~200 calorie reduction in total calorie intake (Stookey, 2007).

Thus caloric beverages represent a significant source of calories for many Americans, yet most do not consume even the minimum amounts of water necessary to maintain adequate hydration. Given the struggles many Americans have in managing their weight, replacing sweetened, non-nutritious beverages with water may be an ideal public health message to both achieve an adequate water intake and facilitate weight management.

Best wishes,
"Dr. Water" IPWR Fellow Brenda Davy, Ph.D., RD

Do you have a question about drinking water? Where it comes from? How it is cleaned? Why does it smell like chlorine? How much do you need to drink every day? Or, where to find information about your drinking water? "Dear Dr. Water" can help you. Send your question to dr.water@ipwr.org. Selected inquiries will be answered in the next issue of At Your Tap.

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