Feature Articles: Food, Fitness and Health
Drenching the Water Myths
Janet Hackert, Northwest Regional Nutrition and Health Education Specialist, University of Missouri Extension
Water is crucial for human life. On average, blood is 92 percent water and other parts of the body such as muscles and brain are 75 percent water. Water is needed to control body temperature, to lubricate and cushion joints, to transport nutrients and to remove waste.
Water is an essential nutrient, yet there may be some misconceptions about it. The July 2008 issue of Tufts University Health and Nutrition Letter dispels some of these myths.
Myth: People require eight 8-ounce glasses of water daily to stay hydrated.
In 1945 the Nutrition Council found that people do need approximately 64 ounces of water every day. But that can come from drinking straight water or from other beverages like milk and juice. It can also come from foods. The water content in some foods is more obvious than others. For example, it is no surprise that watermelon is 91 percent water by weight and grapefruit is 89 percent. But you might not know that broccoli is also 89 percent water by weight and carrots are 88 percent. Roasted chicken with no skin is 65 percent and even whole wheat bread is 38 percent!
Myth: Caffeinated beverages such as tea, coffee and soda don’t count in getting enough water for the day.
Actually, caffeine does have a diuretic effect (that is, it draws water from the cells), but a person would have to consume a huge amount for this to take place.
Myth: By the time people feel thirsty, they are dangerously dehydrated.
In a healthy adult, thirst comes when blood is concentrated by about 2 percent. Dehydration is defined generally as concentration by about 5 percent. According to the Institute of Medicine, “Fluid intake, driven by thirst… allows maintenance of hydration status and total body water at normal levels.” So drinking to satisfy thirst works to maintain that balance. A caution would be for older adults for whom the sensation of thirst does not kick in as quickly. Especially on hot summer days (or cold, dry ones), older adults should be a little more conscientious about staying hydrated.
Last update: Friday, September 20, 2013