much is enough?
The notion that water might be bad for you is not something you will hear from the bottled water industry. Instead, bottled water companies cling to the "8 x 8" rule as gospel truth:
That's from the International Bottled Water Association, May 14, 2003.
Curiously, Rockefeller does not -- never did -- have a Nutrition Information Center. We'll get back to that, but first, where did the 8 x 8 rule originate?
Not drinking enough?
In August, 2002, Valtin outlined his results. "I could not find the origin, any scientific basis," he told us. "I spent 10 months searching with the help of a really expert librarian, and we found nothing."
In his article, Valtin asked readers to report any overlooked evidence. But since then, he says, "not a single scientific report has been brought to my attention. At first I said I could find no scientific evidence. Now I feel more secure in saying that there appears to be none, or is none."
A likely source for the oft-repeated advice, Valtin said, was a 1945 study from the National Academy of Sciences, which said a healthy, fairly sedentary adult needs about two quarts of water a day. So far, so good. But in the next sentence, the "the recommendation said that most of the water can be obtained from solid foods," Valtin says. In developing the 8 x 8 rule, "That second sentence was missed, ignored, or lost over time," he adds. Ironically, a study group of the same National Academy of Science is due to issue a water-consumption advisory in September.
Still, many nutritionists like 8 x 8, and nobody questions the need to drink some water. Heidi Reichenberger, a Boston spokesperson for the American Dietetic Association, for example, says drinking lesser amounts could cause subtle health deficits "that people might not identify with dehydration," such as feeling sluggish or having dry skin. Water plays a role in regulating body temperature, lubricating joints, and helping digestion, she says, "so if you are mildly dehydrated, you may be slightly off, but not at a level where you would notice anything."
Still, Reichenberger admits" we are not really sure where the number [8 x 8] came from. Some studies show that you may not need that much, but it depends on many factors, activities, climate, age, gender. 8 x 8 may not be perfectly correct for everyone, but it's safe, not too much, it's a good guideline to follow when most people aren't drinking enough fluids."
Nutritionist Barbara Levine, who co-directs the Human Nutrition Program at Rockefeller University, wrote a stronger retort to Valtin's 2002 study. "The 8x8 guidance has been a standard in the health profession and there are many published, peer-reviewed scientific studies that unquestionably demonstrate the crucial role of water in the human body." Levine is a consultant to IBWA and is director of the Nutrition Information Center at Weill Medical College in New York.
Her response, however, does not contradict Valtin. The retired kidney specialist did not dispute the need for water, but simply pointed to the lack of scientific evidence for a rule that has, as Levine mentioned, "been a standard in the health profession."
Valtin says healthy people can let thirst be a guide to drinking. One of the main functions of the kidney, he says, is to maintain water balance, and "my focus is the system that keeps us in water balance. That system is very sensitive, very quick and very accurate in restoring the amount of water lost."
Within limits, Valtin says, a healthy person who drinks too little water "will not be sick because less will be excreted."
Not winning a popularity contest
Perhaps. But the industry has not been shy in advocating the guzzling of 2 quarts per day, and until this week it did so by linking the recommendation to Rockefeller University, a venerable name in health research. Press releases and studies from the IBWA (and widely echoed at other websites) trumpeted the 8 x 8 rule -- and prominently mentioned Rockefeller University.
The linkage between the bottled water industry and Rockefeller University did not amuse the University. When Rockefeller's director of communications Joseph Bonner was shown several references to the supposed collaboration between the University and the "Human Nutrition Center" at Rockefeller University, he responded thus: "We did not receive any money from this group [the IBWA], and have no relationship with the International Bottled Water Association... and we certainly don't endorse the concept of drinking eight eight-ounce glasses of water a day. We have sent IBWA a sharply worded letter to ask them to take it off their web site."
While Kay acknowledged that the linkage was an accident and "we are working to correct it so it's clear that it's an IBWA survey and not Rockefeller," the IBWA website was still linking the trade association with the University when we visited on a week later, on May 19.
Coffee, tea or H20?
"Beverages that best meet hydration needs include water, juices, milk or caffeine-free coffee or tea," says the American Dietetic Association. You get similar advice from MonsterMoving.com (a website devoted to "changing the way people move" -- notice how they repeat the non-existent association between Rockefeller and IBWA): "The Nutrition Information Center at The Rockefeller University offers the following tips for maintaining proper hydration... Don't substitute beverages with alcohol or caffeine for water. Caffeine and alcohol act as diuretic beverages and can cause you to lose water through increased urination.... (Source: Nutrition Information Center at The Rockefeller University. As reported on the IBWA web site.)"
Coffee, tea or ?
One final note. Bottled water may taste better than what comes out of your tap (although the Why Files blind taste testers did describe one spring water as "slightly smelly, slight taste," "kinda salty," "definite chem taste." But bottled water is no better than Tappier when it comes to hydration, says Reichenberger. "In some areas it may taste better than tap water, and it certainly is convenient, but beyond that, there is nothing wrong with tap water, and there is no benefit from bottled water."
Despite the curious goings-on regarding the 8 x 8 rule, Valtin said, "I will not say [8 x 8] is deliberately misused. I think it's obvious that the bottled water industry loves it, but I think it's not just a conspiracy of the bottled water industry, but it's so ingrained in virtually all training magazines, health magazines, websites; most nutritionists in this country think it's a good rule."
Here's a good rule: always check the bibliography.
©2003, University of Wisconsin, Board of Regents.