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Health January 2013

Aid for Age

Eight Glasses of Water a Day? Pure Fiction

By Tait Trussell

“Consider that first commandment of good health: Drink at least eight 8-ounce glasses of water a day. This unquestioned rule is in itself a question mark. Most nutritionists have no idea where it comes from.”

One of the most prevalent recommendations in the field of health doesn’t hold water. Specifically, the urging that everyone — young and old — should drink eight glasses of water a day.

As Snopes.com put it: “you need to drink eight to ten glasses of water per day to be healthy” is one of our most widely known basic health tips. But do we really need to drink that much water?

In general, to remain healthy, we need to take in enough water daily to replace the amount we lose through excretion, perspiration, and other bodily functions. That amount varies from person to person.

A Los Angeles Times article, for example, reported: “Consider that first commandment of good health: Drink at least eight 8-ounce glasses of water a day. This unquestioned rule is in itself a question mark. Most nutritionists have no idea where it comes from.”

“I can’t even tell you that,” says Barbara Rolls, a nutrition researcher at Pennsylvania State University, “and I’ve written a book on water.”

Some say the idea was derived from fluid intake measurements made decades ago among hospital patients connected to IVs who were elderly and prone to dehydration.

Kidney specialists seem to agree that the eight glasses of eight ounces is a gross overestimation of any required minimum. An average size adult, say, a 60 year old, loses ten cups of fluid a day, but takes in four. That may be plenty. Some medical experts believe we could cover our minimum daily water needs by drinking little if anything during the day.

Some nutritionists are convinced that much of the population is dehydrated. They believe we drink too much coffee, tea, and sodas with caffeine. This causes the body to lose water, they maintain. And when we are dehydrated, we don’t know enough to drink water.

“The notion that there is widespread dehydration has no basis in medical fact,” says Dr. Robert Alpern, former dean of the Medical School at the University of Texas Southwestern Medical Center in Dallas, now at Yale Medical School.

Many doctors say the infatuation with water as an all-purpose health potion — ranging from a tonic for the skin to a key to weight loss — is a combination of fashion and fiction.

Probably the best advice is: If you feel thirsty, drink. Water, of course, is essential to your survival. Obviously, if you live in a tropical climate and are exercising in the heat, you need more fluid intake.

Writing in the American Journal of Physiology, Heinz Valtin of Dartmouth Medical School said: “Despite the seemingly ubiquitous admonition to “drink at least eight 8-ounce glasses of water a day (with an accompanying reminder that beverages containing caffeine or alcohol do not count) rigorous proof of this counsel appears to be lacking.”

A review of electronic databases and extensive consultations with nutritionists who specialize in the field of thirst turned up no scientific support of the 8x8.

A study in the American Journal of Clinical Nutrition concluded, “Healthy older adults maintain water input, output and balance comparable to those of younger adults and have no apparent change in hydration status."

One matter seldom, if ever, dealt with in the scientific literature but pertains to the aging is the admonition not to drink a lot of any liquid in the evening. If so, for many seniors, it will mean the need to rise from bed several times during the night to visit the bathroom.

 

Tait Trussell is an old guy and fourth-generation professional journalist who writes extensively about aging issues among a myriad of diverse topics.

Meet Tait