Doggcrappin luojan, Dante Trudelin mietteitä vuosien takaa, lihavoinnit minun tekemiä:
To date there is no published evidence that a high protein diet produces any negative effect on
metabolism in bodybuilders or any other type of athletes.
Recently, a comprehensive study completed by Jacques Poortmans and Oliver Dellalieux
(published in Int. J. Sport Nutr. & Exerc. Metab. 11;28-35:2001) at the University of Brussels in
Belgium investigated this aspect directly.
These scientists assessed whether high protein diets affect the health and kidney function of
bodybuilders and other athletes. Their study involved 20 bodybuilders and 18 other highly trained
athletes that consumed a high protein diet. (Approximately 2 grams of protein per kilogram of
body weight per day. More than double the recommended daily allowance.)
Their diets were analyzed to provide total calorie, protein, fat, carbohydrate, and calcium intake
each day. Blood and urine samples were taken from the athletes and spectrum of analyses were
performed looking at glomerular filtration rate (creatinine clearance), potential change in
glomerular membrane permeability (albumin excretion rate), urea and uric acid clearance,
nitrogen and calcium balances and any modification in kidney free water balance.
In addition to the resting condition, the researchers also wanted to obtain other data that would be
important to hard training athletes. Very intense exercise temporarily impairs kidney function (a
natural, safe, and regular process). However, the research wanted to see if a high protein diet
would produce a detrimental impact on this physiological aspect. So analyses were performed
before and directly after a bout of very intense (cycling) exercise.
Some of the athlete's in the study were documented to have protein intakes as high as 2.8 grams
per kilogram of body weight per day. However, when the results came in, the high protein athletes
showed no fundamental differences that could be associated with damage or impaired kidney
function in any way.
These athletes did show higher values for creatinine and uric acid clearance, However, all
readings fell within the upper limit of normal levels. Despite the high protein intake there was no
accumulation of urea, demonstrating no toxicity. Glomerular filtration rates were normal and there
were no signs of even moderate hyperfiltration. This aspect is important.
Hyperfiltration seems to precede the excess excretion of protein plasma into the urine. It is an
indicator of the amount of "stress" on the kidneys. The albumin clearance rates also supported
the observation that a high protein diet does not stress healthy kidneys. In fact, all readings taken
from these athletes proved absolutely normal. Their kidney function was in no way effected by a
high protein diet.
The combination of high protein intake and intense exercise didn't appear to impair any aspect of
kidney function either. The reduction of several clearance rates as a result of the intense exercise
were in line with other reported observations in exercising humans.
The scientists responsible for this research concluded that high protein intakes of 170 to 243% of
the RDA show no toxicity, dehydration, calcium loss or impairment of kidney function. Also, the
researchers cautioned that some of the upper-end clearance ranges of some clinical markers
witnessed in this study are not solely related to a high protein diet as many other individual
differences play a big part in this regard.
The researchers concluded and recommended that high protein diets should not be used as an
"escape goat" to explain these variations.
So what are the medical facts behind these claims and why do so
many people, including some medical professionals and nutritionists, still believe it? For starters,
the negative health claims of the high protein diet on kidney function is based on information
gathered from people who have preexisting kidney problems. You see one of the jobs of the
kidneys is the excretion of urea (generally a non toxic compound) that is formed from ammonia (a
very toxic compound) which comes from the protein in our diets. People with serious kidney
problems have trouble excreting the urea placing more stress on the kidneys and so the logic
goes that a high protein diet must be hard on the kidneys for healthy athletes also. Now for the
medical and scientific facts. There is not a single scientific study published in a reputable peer -
reviewed journal using healthy adults with normal kidney function that has shown any kidney
dysfunction what so ever from a high protein diet. Not one of the studies done with healthy
athletes that I mentioned above, or other research I have read, has shown any kidney
abnormalities at all. Furthermore, animals studies done using high protein diets also fail to show
any kidney dysfunction in healthy animals. Now don't forget, in the real world, where millions of
athletes have been following high protein diets for decades, there has never been a case of
kidney failure in a healthy athlete that was determined to have been caused solely by a high
protein diet. If the high protein diet was indeed putting undo stress on our kidneys, we would have
seen many cases of kidney abnormalities, but we don't nor will we. From a personal perspective
as a trainer for many top athletes from various sports, I have known bodybuilders eating
considerably more than the above research recommends (above 600 grams a day) who showed
no kidney dysfunction or kidney problems and I personally read the damn blood tests! Bottom
line? 1-1.5 grams or protein per pound of bodyweight will have absolutely no ill effects on the
kidney function of a healthy athlete, period. Now of course too much of anything can be harmful
and I suppose it's possible a healthy person could eat enough protein over a long enough period
of time to effect kidney function, but it is very unlikely and has yet to be shown in the scientific
literature in healthy athletes.
So what about the osteoporosis claim? That's a bit more complicated but the conclusion is the
same. The pathology of osteoporosis involves a combination of many risk factors and
physiological variables such as macro nutrient intakes (carbs, proteins, fats), micro nutrient
intakes (vitamins, minerals, etc), hormonal profiles, lack of exercise, gender, family history, and a
few others. The theory is that high protein intakes raise the acidity of the blood and the body must
use minerals from bone stores to "buffer" the blood and bring the blood acidity down, thus
depleting one's bones of minerals. Even if there was a clear link between a high protein diet and
osteoporosis in all populations (and there is not) athletes have few of the above risk factors as
they tend to get plenty of exercise, calories, minerals, vitamins, and have positive hormonal
profiles. Fact of the matter is, studies have shown athletes to have denser bones than sedentary
people, there are millions of athletes who follow high protein diets without any signs of premature
bone loss, and we don't have ex athletes who are now older with higher rates of osteoporosis. In
fact, one recent study showed women receiving extra protein from a protein supplement had
increased bone density over a group not getting the extra protein! The researchers theorized this
was due to an increase in IGF-1 levels which are known to be involved in bone growth. Would I
recommend a super high protein diet to some sedentary post menopausal woman? Probably not,
but we are not talking about her, we are talking about athletes. Bottom line? A high protein diet
does not lead to osteoporosis in healthy athletes with very few risk factors for this affliction,
especially in the ranges of protein intake that have been discussed throughout this article.
Another group of researchers in the field of protein metabolism have come to similar conclusions
repeatedly. They found that strength training athletes eating approximately the RDA/RNI for
protein showed a decreased whole body protein synthesis (losing muscle jack!) on a protein
intake of 0.86 grams per kilogram of bodyweight. They came to an almost identical conclusion as
that of Dr. Lemon in recommending at least 1.76g per kilogram of bodyweight per day for strength
training athletes for staying in positive nitrogen balance/increases in whole body protein
synthesis.
There is evidence (see papers by Peter Lemon) that intense activity may
increase protein requirements in order to maintain a positive nitrogen balance and avoid the loss
of lean muscle tissue. The most recent requirements for athletes in intensive training (a term
which requires definition as it may be that some threshold may exist for when additional protein
above the RDA of .8 g/kg bodyweight is required) are: Strength athletes: 1.8 g/kg bodyweight and
I've seen up to 2g/kg suggested as possible more effective. Data from Tarnpolosky with
European athletes shows that massive protein intakes of up to 3.5 g/kg further increase lean
mass gains. In the early 1970’s, a study of weightlifters showed that these athletes needed at
least 2.2 gr/kg. Two decades later Russian research demonstrated better muscle increases with
4.2 gr/kg.
Doggcrapp: Tarnpolosky trained with natural and sauced athletes and noted that every athlete
was gaining at advanced rates from the higher figures than the lower 1.8 or so---Dehydration is
the main culprit people must watch out for on high protein diets but anyone who is a bodybuilder
who is drinking less than a gallon a day is cheating himself already
eli onko oikeesti jotai haittaa osaako joku sanoa asiallisesti jos tietää, kiitos?
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