High-protein diets dehydrate even the very fit
 

By E. J. Mundell

NEW ORLEANS, Apr 22 (Reuters Health) - High-protein diets place such a strain on the kidneys that even very fit athletes can become dehydrated, according to researchers.

"Personally, I would not recommend a protein intake of over 2 grams of protein per kilogram of weight per day, as it may have negative long-term effects," said researcher William Forrest Martin, a graduate student at the University of Connecticut in Storrs. He presented the findings here Monday at the Experimental Biology 2002 conference. (Note - 1 kg = 2.2 lbs ... Doreen)

High-protein diets have surged in popularity in recent years for their purported potential for quick weight loss. Most of these plans promise prompt results if devotees fill up on steak, bacon, fried eggs and other high-protein foods, while cutting back on carbohydrates such as potatoes, pasta, vegetables and fruit.

But the diets have their critics. For example, the American Heart Association recently issued a report that found that there was "no scientific evidence" that the diets actually worked to keep pounds off over the long term, and they may trigger unwanted side effects such as fatigue or dizziness.

In their study, Martin and his colleagues sought to determine the effects of such diets on hydration--the body's ability to distribute and retain a healthy amount of water. They had five very fit endurance runners consume low-, medium- and high-protein diets over three successive 4-week periods. During the high-protein diet phase, participants consumed about 30% of their total calories from foods such as eggs, steak and "power bars."

Blood tests conducted on the athletes 3 weeks into the diets revealed "that increasing protein intake led to a progression toward hypo- (low) hydration, and that a greater strain was placed upon the kidney due to the excessive levels of protein intake," according to Martin.

Speaking with Reuters Health, he explained that increased protein intake leads to an excess build-up of nitrogen in the blood. "In the end, the nitrogen ends up at the kidney in the form of urea where it needs to be filtered out and excreted in the urine."

The excessive urination triggered by high protein intake can easily lead to a hypohydrated state, even in the absence of symptoms. In fact, all of the runners in the study said they felt no more thirsty while on the high-protein diet compared with other regimens--even though their levels of hydration had fallen to below healthy levels.

Based on the findings, Martin advised active individuals to avoid getting a large percentage of their calories from meat, eggs and other protein-rich foods. But "if one does embark on a diet greater than about 1.8 grams per kilogram of body weight per day, I would suggest they increase their daily fluid intake to protect against dehydration," he said.

According to the American Dietetic Association, the average adult should consume between 8 to 12 cups of water per day.

http://health.yahoo.com/search/heal...=s&p=id%3A20631

The statement that one should limit one's daily protein intake to 2 g/kg body weight sounds reasonable. For me, this would be about 120 g of protein. I don't get anywhere near that: more like 60-70 g per day.

But:

<i>"High-protein diets have surged in popularity in recent years..." </i>

Really? I haven't heard of a diet that recommends that much protein. Unless someone can enlighten me? Is Atkins that high?

*sigh* When are people going to get it? Read my lips: reduced carb is not the same as high protein!

Atkin's is 70 to 80 percent fat, 20 to 25 percent protein and 5 percent carbs. That is about the break down of it.

I think I range 60 to 80 grams of protein a day.

I hate research like this that mistakes a low carbohydrate diet as a high protein one as well.

Actually, the real crime in this report is that it's scare mongering based on insufficient data and evidence.Five people, and no control group is NOT research. This is merely an experiment. It's also worth noting that the five subjects did not restrict carbohydrate intake during the "experiment".Indeed. This is what normal, healthy kidneys do. This is not an added stressor or something harmful to kidneys, this is exactly their role and function. To state that increasing the amount of urea increases workload on the kidneys and will therefore be damaging, is like saying exercise is harmful to the heart and lungs because it makes them work harder to take in oxygen and get rid of the excess carbon dioxide and lactate that builds up in the blood. :daze: duh!!

Excessive protein CAN be stressful to kidneys that are already damaged and diseased.Common sense. If the solution is so simple and obvious, then why the scare tactics and campaign against protein as if some sort of irreparable damage will ensue???

:bash:

Doreen

DUH!!
 

Let's see....activities that make your body organs work harder is bad? Okay...guess that means I should stop exercising immediately as it makes my muscles work harder and causes a buildup of lactic acid. It also makes my heart work harder and causes a buildup of carbon dioxide in my blood that my lungs have to work overtime to exchange for oxygen. Guess I should stop thinking because that could strain something in my brain. NOT! No serious scientist would suggest that we stop thinking or exercising because it causes "strain" to those body organs. How about this? We should stop consuming excessive amounts of carbohydrates because it causes our pancreas to work overtime producing insulin that our bodies will eventually become resistant to and places a strain on our livers to convert all that excess glucose swimming around in our bloodstreams. We should stop consuming excessively low amounts of dietary fat because it causes or livers to work overtime producing the dietary cholesterol that we aren't getting and it makes the bad LDL kind when it does. Drink 8-12 glasses of water when you eat a diet higher in protein? I thought that was the recommendation for everyone regardless of what type of diet they are following. The "study" above is not a study but a poorly run experiment that shows nothing other than how stupid things can get published without sufficient data to back them up (some poor professor must have been facing a "publish or perish" dilemma). 5 subjects? No control group? Give me a break! This type of fear mongering is inexcusable.

What's wrong with drinking water? ;)
------

Thursday April 25, 2002

Press Release

SOURCE: American Kidney Fund

American Kidney Fund Warns About Impact of High-Protein Diets on Kidney Health

ROCKVILLE, Md., April 25 /PRNewswire/ -- The American Kidney Fund (AKF) is warning Americans about popular high-protein diets for weight loss. The diets place such a significant strain on the kidneys that even conditioned athletes can become dehydrated, according to researchers at the University of Connecticut.

AKF Chairman of Medical Affairs Paul W. Crawford, MD said, ``We have long suspected that high-protein weight loss diets could have a negative impact on the kidneys, and now we have research to support our suspicions. Dehydration forces the kidneys to work harder to clean toxins from the blood. Kidneys not only filter the blood, but they help regulate blood pressure and the number of red blood cells.''

The researchers studied five fit endurance runners who consumed a low, then a medium, and finally a high-protein diet. During the high-protein phase, the runners consumed about 30% of their total calories from foods such as eggs, steak, and so-called ``power bars.'' Blood tests showed that increasing the protein intake led to a progression toward dehydration, and that a greater strain was placed on the kidneys due to the excessive amount of protein.

``Increased protein intake leads to a build-up of nitrogen in the blood. The nitrogen ends up at the kidney in the form of urea, where it needs to be cleaned from the blood and gotten rid of in the urine,'' explained Dr. Crawford. ``The resulting increase in urination can cause dehydration, further straining the kidneys,'' he added.

In otherwise healthy individuals, a protein intake of no more than 2 grams of protein per kilogram of body weight was recommended by the researchers in order to avoid negative long-term effects.

Dr. Crawford also discussed the risk that bodybuilders take in eating high-protein diets while building muscle. He noted, ``Bodybuilders could be predisposing themselves to chronic kidney disease because hyperfilteration (the strain on the kidneys) can produce scarring in the kidneys, reducing kidney function.''

``Chronic kidney disease is not to be taken lightly, and there is no cure for kidney failure. The only treatments are kidney dialysis and kidney transplantation. This research shows that even in healthy athletes, kidney function was impacted and that ought to send a message to anyone who is on a high-protein weight loss diet,'' concluded Dr. Crawford.

The American Kidney Fund is the leading national voluntary health organization providing direct financial assistance for the benefit of kidney patients supported by comprehensive educational programs, clinical research and community service projects.

SOURCE: American Kidney Fund

http://biz.yahoo.com/prnews/020425/dcth005_1.html

Is it just me or do 'They' seem worried of late? That's a lot of publicity in one week. Right on the heels of all the information about carbs and cancer (it's everywhere here today, news, radio, TV). It feels almost like a preemptive strike - get them before we look even worse.

Nat

Yet another: High-Protein and Dehydration
 

Some Foods Raise Dehydration Risk
Sun May 5,12:02 PM ET

By IRA DREYFUSS, Associated Press Writer

WASHINGTON (AP) - What athletes take in may dry them out. Fast foods like hamburgers and carbonated drinks such as sodas can wind up causing dehydration, experts say.

Sugary, caffeine-packed soft drinks, in particular, can cause trouble, said Dr. Gary I. Wadler of New York University School of Medicine. A cola's sugar and the carbonation can make a person feel full without providing enough liquid.

"They are very sweet, so you get bloated. They are gaseous, so they distend you, so you get more bloated," Wadler said. And caffeine, which tends to increase the flow of urine, "is a double whammy," he said. "You lose on all counts."

Former tennis star Jimmy Connors used to be one of Wadler's patients.

"He used to get these horrific total body cramps. It was sort of a mystery," Wadler said. "I found out he was drinking cola drinks in great quantity, and he was getting bloated. Because he was bloated, he was not drinking adequate fluids."

The risk is not limited to sodas, researchers say. Protein breakdown requires water, and the protein in a couple of fast-food hamburgers can leave people dehydrated, a researcher said.

"We didn't have to make them sweat," said nutrition researcher Catherine Jackson who conducted a dehydration study. "The hamburger meat was enough."

Although her study did not measure athletic performance, the amount of dehydration would have been enough to make an endurance athlete perform worse, said Jackson, who works at California State University, Fresno, and is also spokeswoman for the American Dietetic Association. The study was conducted to help NASA (news - web sites) develop rehydration fluids for astronauts. It was published as a NASA internal memo in 1992.

Time spent sleeping also leaves people dehydrated, so the researchers had their test subjects eat the burgers before bedtime, to make the dehydration worse.

A separate study presented last month in New Orleans at Experimental Biology 2002, a conference of seven research-oriented professional societies, found that athletes who took in more protein wound up more dehydrated.

"The concern is that increasing protein increases the work the kidney has to do, and can impact the amount of fluid needed to get rid of waste," said researcher Nancy Rodriguez of the University of Connecticut.

That study, led by graduate student William F. Martin, examined five members of the university's track team. The athletes were placed on supervised high-, medium- and low-protein diets. All the athletes spent a month on each level. "We fed them everything they ate for the four weeks of the diet," said Rodriguez, senior author of the preliminary report.

The low-protein diet worked out to about 68 grams a day for a 150-pound person; the medium-protein, to 123 grams, and the high-protein, to 246 grams.

The low protein diet was mostly grains, augmented by some beef and dairy foods, Rodriguez said. The medium-protein diet was equivalent to the level that athletes ? and most Americans ? normally have, she said. The high-level diet was mostly meat, supplemented by nutrition bars to add to the protein intake, she said.

The high level would be very unusual, but not uncommon for body builders, football players and others trying to add much muscle, Rodriguez said.

The athletes also got bottled water, and filled out forms each day on how much water they drank from any source, Rodriguez said. "I was very conscious of keeping them hydrated," she said.

As the amount of protein rose, the athletes' kidneys had to work harder as the body tried to get rid of the excess protein, the study found. There was a higher proportion of protein breakdown chemicals such as nitrogen in the urine of athletes on the high-protein diet.

The researchers took those findings as signs that athletes on high-protein diets were losing more water. And because there was no evidence the athletes were drinking more, the scientists concluded the men were dehydrated.

It doesn't take much dehydration to reduce an athlete's ability to perform. Being about 1 percent below optimal fluid level can reduce exercise performance. Rodriguez said her study did not test performance because testing could have impaired the athletes' readiness to compete.

But the athletes did not notice being more thirsty, and did not report drinking more, as their protein levels rose, the study found.

___

On the Net:

American College of Sports Medicine statement on dehydration: http://www.acsm.org/pdf/DEHYEST.pdf

American Dietetic Association: http://www.eatright.org/


http://story.news.yahoo.com/news?tm...s_dehydration_1

The study with athletes and high protein was posted last week here. They found that the dehydration occurred when athletes consumed in excess of 2g protein per kg of body weight. 1kg = 2.2 lbs. That's a lot of protein, and a person would have to be intentionally eating very large portions of meat, and adding protein shakes or other supplements during the day.

Most low-carbers are consuming average, adequate amounts of protein. Drinking lots and lots of water is good common sense in any regard :)

Doreen

Oops, didn't realize they're talking about the same study. They're now merged into one thread.

Wa'il