The Doctor Weighs In

By Dov Michaeli MD, Ph.D

A recent editorial in the Journal of the American Society of Nephrology reviewing all the evidence to back up the claims of “drink 8 glasses of water a day” drew my attention to the whole subject of “medical myths”. Every physician could attest to episodes of irate true believers refusing to accept any criticism or skepticism. To my astonishment, I came across many physicians who vehemently believe in those urban myths. It is a curious observation of mine: There exists an inverse correlation between the amount and quality of the evidence and temperature: the less light the greater the heat. It is as if you attacked a central tenet of their beliefs, shaking up their view of the world. Even in scientific meetings I have witnessed many heated arguments, where hand waving and personal insults were  substitutes for solid data.

So with this in mind, I am going to put my life on the line and try to debunk as many medical myths as come to mind. Feel free to send poison mail. Or maybe, if you can think of a myth, email me and I promise to protect your identity.

The claims that drinking 8 glasses of water a day is good for you

There are numerous claims of health benefits of drinking lots of water, but the most oft-repeated ones are:

· It increases your skin tone, keeps it hydrated, and gives it a youthful appearance.

· It washes out toxins accumulating in the body.

· It suppresses appetite and aids in weight-loss diets.

· It prevents sports injuries.

· And finally, the blanket claim: it increases longevity.

Where did those claims come from?

Here are some fascinating historical findings, some of which I found in Slate Magazine’s The Explainer column by Nina Shen Rastogi:

•  How long was this myth around? Answer: the 8x8 (eight 8 oz glasses) myth going all the way back to 1796, in a German text by Dr. Christoph Wilhelm Hufeland called Makrobiotik. The book includes an anecdote about the surgeon general to the king of Prussia, a vibrant 80-year-old man who had "contracted the habit of drinking daily from seven to eight glasses" of cold water and thus "enjoyed much better health than in his youth." (An English translation of this book was published 1843.)
• Fast forward to the 19^th century: The hydrotherapy craze that swept through Europe and then America in the late 19^th century encouraged the notion that people needed to be drinking more water.
• By 1900, the New York Evangelist reported that a women's association on the Lower East Side was being instructed by a Dr. Vinton that one needed to ingest "at least eight glasses of water a day" and take "four times as much water as food." (Incidentally, the girls were also told that it was dangerous to get one's feet wet, that it wasn't good to "wear many skirts," and that their brains were "soft like jelly."). Well, what can you expect from an evangelist, especially from New York ?
• By the 1910s and 1920s, the popular press was full of exhortations to consume six to eight glasses on a daily basis. Charles Atlas, the bodybuilder, was fond of recommending the same amount.

Who can argue with such authoritative sources?

But now for something a bit more authoritative: the U.S. government's Food and nutrition Board. The board's "Recommended Dietary Allowances" from 1945 include the following advice:

“A suitable allowance of water for adults is 2.5 liters daily in most instances. An ordinary standard for diverse persons is 1 milliliter for each calorie of food. Most of this quantity is contained in prepared foods.”

 What the popular, and less popular press, missed was the last sentence, which pointed out that you can get most of that water just by eating. If you actually had to drink all 2.5 liters, you'd need around 10 8-ounce glasses per day.

In more recent decades, there have been plenty of proponents of the 8x8 theory. In 1967, Dr. Irving Stillman, one of the earliest advocates of a high-protein, low-carbohydrate diet, insisted that his followers drink eight glasses of water a day in order to wash away ketones, or "ashes left in the furnace." This doctor, his financial success notwithstanding, would have failed my biochemistry class at UCSF.

The controversial 1992 bestseller Your Body's Many Cries for Water, which calls for a minimum of eight to 10 glasses of pure water a day (not coffee, not soda), probably played a role in spreading the myth, as has the bottled-water industry, which has exploded since the 1980s.

And the scientific evidence?

In a word: none.

The key to debunking these claims is actually in that last sentence of the U.S. Food and Nutrition Board statement of 1945, namely you can get most of your water requirements from food. We can get a bit more scientific about it and point out that animal and plant cells are made up of mostly water. Surprising? The cell cytoplasm is made of a gel, something akin to gello. Did you know, for instance that cucumbers are over 90% water? And so are many other vegetables and fruits.

How much should we drink?

The short answer is: as much as you feel you need to drink. Of course, if you exercise a lot, or live in a warm climate you need to drink more. But don’t sweat it—your body will signal its needs for hydration through dry mucous membranes in the mouth; or if deficit is more pronounced—through orthostatic hypotension, which means a drop in blood pressure when you stand up from a sitting of lying position. You don’t have to measure your blood pressure for that—you will know it when you experience it: you’ll feel dizzy. And if these two signals fail to alert you, pay attention to your urine. If you notice a marked decline in volume and the color turning deeper yellow, it is a signal that your body is trying to conserve  water. Time to replenish the tank.

And yes, coffee, tea, soda—they all count as fluids. The myth that these don’t count because they are diuretic is just that—an undocumented belief.

Take home message

First, don’t believe what you hear. Ask for the evidence; you’d be surprised by answers like “everybody knows that”, or even worse.

And second, for all you H2O guzzlers, take it easy. Drink as much as you feel like, and chalk up rest to water conservation.

By Dov Michaeli MD, Ph.D

Several months ago I received an alarming phone call from my nephew: he had terrific pain in his abdomen which caused him to double over. His stool was pitch black. It was obvious that he had an acute stomach ulcer, probably bleeding. What could cause this painful disease?

Since the late 19^th century doctors described the existence of bacteria in the stomach, but for a variety of reasons these reports did not gain traction, or were simply not believed. The bacterium, later named Helicobacter pylori was rediscovered in 1979 by Australian pathologist Robin Warren, who did further research on it with Barry Marshall beginning in 1981; they isolated the organisms from mucosal specimens from human stomachs and were the first to successfully culture them. In their original paper, Warren and Marshall contended that most stomach ulcers and gastritis were caused by infection by this bacterium and not by stress or spicy foods as had been assumed before. Their report was met with universal disbelief. I remember my own dismissive reaction when I read the first papers. An organism living in such an acidic environment (pH 2-3)? And not as a transient tenant, but a permanent resident? “everybody” knew that stomach ulcer is caused by stress…there must be some mistake here.

The experiment that changed everybody’s mind was when Barry Marshall, in a dramatic effort to convince the medical world, swallowed a petri dish of H. pylori, showed with gastric biopsy that the bacteria indeed colonized his stomach, developed gastritis within weeks after swallowing it, eradicated it with a combination of bismuth subsalicylate (Pepto Bismol) and metronidazole (Flagyl), and a second endoscopy 10 days later confirmed that the gastritis resolved. It was only then, in 1994, that NIH ( the National Institutues of Health) published an opinion stating that most recurrent gastric ulcers were caused by H. pylori, and recommended that antibiotics be included in the treatment regimen. In 2005 Warren and Marshall were awarded the Nobel Prize for their work.

What is H.pylori?

This bacterium is wonderful example of biological adaptation. It burrows into the mucous layer (a gel-like mucus layer) of the stomach, and that’s where it stays. But to survive in this hostile environment it had to somehow protect itself from the acid. Urea is normally secreted by the epithelial cells (these are the cells lining the stomach). The bacteria secrete an enzyme, urease, which breaks down urea to ammonia and CO 2 . Ammonia does a wonderful thing for these bacteria: it neutralizes the acid in the vicinity, thus allowing them to thrive in this forbidding environment. But it does something else: it kills the epithelial cells that come in contact with it. Thus it, and some other proteins secreted by the bacterium, cause gastritis (inflammation of the stomach lining) and eventually, an ulcer.

What about the acid?

We are not completely blameless--H. pylori gets some help from us in causing gastritis and ulcers. Once the mucous layer is damaged by  bacterial colonization, the epithelial cells lie bare and defenseless against the destructive effects of the acid. This can explain the relationship between emotional upset and ulcer disease: stress hormones cause an increased secretion of acid. Coffee has also been shown to increase acid secretion.  Unfortunately, decaffeinated coffee is not going to help;  chemicals that cause increase in acid secretion are present also in decaf. The same is true for excessive alcohol consumption; it damages the mucous layer, and exposes the cells to acid. add to that H. pylori--and you are in trouble.

Eradicate! eradicate?

H. pylori is an ancient organism that has lived in human stomachs probably since the beginning of our species, about 4 million years ago. It is disseminated with the drinking water, and probably infected 100% of the human population before sanitary conditions became widespread in the 19^th and 20^th century. As we saw, the ulcer formation is really incidental, collateral damage, to the ingenious secretion of urease and neutralization of stomach acid. Even more alarming, it is now generally accepted that H. pylori is responsible for most cases of stomach cancer. So obviously, if we just treated this pesky bacterium to a dose of antibiotics-we’d solve the problem once and for all. Indeed, while the incidence of H. pylori infection in humans is decreasing in developing countries, presumably because of improving sanitation and increasing use of antibiotics, in the United States the incidence of gastric cancer has decreased by 80 percent from 1900 to 2000.

However, there are always coseqences; some of them unintended. Parallel to the decrease in H. pylori infection there is an increase in the incidence of acid reflux from the stomach into the esophagus. And even more alarming: esophageal cancer is now the most rapidly rising cancer in the U.S. and Europe.

Fortunately, in most cases we can deal with this problem quite easily: we have now powerful drugs that are called proton-pump inhibitors, such as prilosec, that inhibit acid formation in the stomach and its reflux to the esophagus.

So here is another example of the delicate balance between us and our environment, in this case our internal environment. Recent studies showed that gut bacteria may contribute to obesity or even to our mood. So before we indiscriminately eradicate the flora that inhabited us for millions of years and upset the delicate biological balance we live in, we should carefully consider the consequences.

Dov michaeli MD, Ph.D is in the biotech industry

by Pat Salber, MD

There is a short article by Nicholas Bakalar from NY Times News Service in local papers today.  The jist of the article is that the amount of caffeine in three cups of coffee or tea each day may help older women maintain mental sharpness - unfortunately, there doesn't appear to be an effect in older men.

"Le Study" is from French researchers and is published in the journal Neurology in August 2007.  Karen Ritchie, a researcg durectir with the French National Institute for Health and Medical Research is the lead author.  The study included more than 7,000 men and women, average age 74 years old, who were followed for over four years.  They were asked about their coffee and tea intake and their mental acuity was measured by standard tests of visual skills and verbal recall.  The researchers also collected information from the study participants about their education, income, depression, alcohol, and tobacco use, among other factors.

After controlling for other variables, the researchers found that women at age 65 who drank three or more cups of coffee or tea a day were about 30% less likely to have a significant decline in verbal skills than those folks who consumed a cup or less.

By age 85, caffeine drinking women were 70% less likely to suffer deficits in mental acuity compared with women who drank less than a cup of coffee or tea. 

Lead author Ritchie said in the NY Times article "please don't rush out and start drinking coffee.  To suddenly start drinking large quantities of coffee is still really premature as a preventive measure."

In the course of my medical career, coffee has gone from good to bad and now back to good again.  It's hard to say what to make of this latest study.  I would say it is probably a safe course, if you enjoy drinking coffee, to continue to consume it in moderate quantities.  I would wait for confirmatory studies before rushing to Starbucks or Peets to load up on coffee beans as a prophylactic measure against Alzheimers or other age-related declines in mental sharpness.