Volume 1  Number 9  December 31, 2004
Second Opinions

Awash in a Bottle of Water: Fashion vs. Frugality

"Whiskey is for drinking; water is for fighting over."
-- Mark Twain, 1884

No one need dispute the obvious benefits of water drinking to the bottled water industry. Over half the population of the U.S. drinks bottled water, often paying up to 1000 times more than the cost of tap water. While Americans presently consume more than 5 billion gallons per year of bottled water at an average retail cost of $6.00 per gallon, ($1.59 for two liters of Aquafina or Pepsi Cola brand waters), we continue to complain bitterly about the $2.00 per gallon cost of gasoline. Is buying bottled water pouring money down the drain; or worse, is it really good for our health compared to tap water? Senior attorney Erik Olson of the Natural Resources Defense Council (NRDC) explains that the FDA has never adopted all the EPA regulatory drinking water standards, and has not even ruled on some points after years of inaction. According to the NRDC up to 40% of bottled water is actually bottled tap water, while the FDA rules allow bottlers to call their product "spring water" even though it may be from a pumped well and treated with chemicals. Some interesting labels NRCD observed include:

" 'Spring Water' (with a picture of a lake surrounded by mountains on the label..Was actually from an industrial parking lot next to a hazardous waste site."

" 'AlasikaTM Alaska Premium Glacier Drinking Water: Pure Glacier water From the Last Unpolluted Frontier, Bacteria Free'...Apparently came from a public water supply. This label has since been changed after FDA intervention."

NRDC's study included "testing of more than 1,000 bottles of 103 brands of bottled water… about one-third of the waters tested contained levels of contamination -- including synthetic organic chemicals, bacteria, and arsenic -- in at least one sample that exceeded allowable limits under either state or bottled water industry standards or guidelines."

Some key differences between testing requirements for tap vs. bottled water, are shocking, for example, disinfection of bottled water, filtration for pathogens and testing for Giardia and Cryptosporidium are not required, but are mandatory for big city tap water, see this article and this report.

How Much Water Should we Drink?

Quite aside from questions about the source of our drinking water, how much water should we ingest to maintain health? As with the proponents of the bottle-carrying water-drinker, we are drowning in advice that more water is better for us. We inhabit an aqueous world of received truth, whether in the guise of science, religion, or fashion. Must we force down eight to ten or more glasses of water a day or follow the advice so often given to fitness enthusiasts and athletes to "stay ahead of your thirst; drink as much as you can"? Quoted in The New York Times, USA Track and Field, the national governing body for track and field, admits in a major revision of its guidelines, that this advice is wrong. They now claim that endurance athletes consuming large volumes of water over the course of long events risk seizures, respiratory failure, and even death. Dr. David Martin, an exercise physiologist at Georgia State University who co-authored an advisory statement for the International Marathon Medical Directors Association says that the old advice on water gorging is wrong.

Excess fluid ingestion during extreme or prolonged exercise can result in expansion and dilution of extracellular fluid volume leading to a potentially dangerous condition known as hyponatremia or low serum sodium. This condition can occur during extreme physical exertion when the intake of water is such as to overcome the kidneys' ability to excrete a maximally dilute urine. Many mechanisms contribute to this, including salt delivery to the diluting segments of the kidney, pituitary hormone effects, etc. Low serum sodium also results from increased water ingestion (polydipsia), the latter occurring in 3%-5% of institutionalized patients with mental illness!

In people constantly drinking excessive amounts of fluid, there is some clinical and experimental evidence that severe chronic over-hydration can lead to loss of kidney (renal) concentrating ability. In a paper published in The American Journal of Physiology, Dr. Heinz Valtin of Dartmouth Medical College stated he could find no scientific support for the common advice for healthy adults to drink at least eight glasses of water a day. Claims have been made that benefits of excess water drinking include maintenance of general health, relief of constipation, reduced fatigue, enhanced alertness, relief of hangovers, prevention of osteoporosis in women, etc. None of these claims have ever been validated in rigorous scientific studies. Dr. Valtin states, "In my opinion, the vast majority of healthy people do not need that much water."

Dr. David Martin goes even further, saying: "People have been carrying bottles of water with them. Some people actually get water intoxication syndrome. They feel lethargic from drinking too much. I worry about the sanity of those people."

It seems, perhaps, that the best general advice for your health and possibly your pocketbook is simply to drink when you feel like it, or when you're thirsty.

Martin F. Sturman, MD, FACP

Copyright 2004, Mathemedics, Inc.

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