Protein Misconceptions

[DOGGCRAPP]

It is interesting to note that Consolazio et al. (1975) Marabel et al. (1979), and Dragan et al. (1985) all reported larger increases in strength, lean body mass (LBM) and nitrogen with much higher protein intakes (3.3, 2.8, and 3.5 g/kg/d respectively). These reports tend to corroborate the more anecdotal beliefs of weight lifters that extremely high dietary protein intakes are essential for optimal muscular development.

Ill be back to join this debate a lil later tonite Im hungry and I have to go eat some more protein honestly. Oh trust me I have alot im going to throw on this thread--my favorite places folder should take me about 6 hours to get thru

 

[DOGGCRAPP]

Will Brink

Myth #2 "High protein diets are bad for you"

So the average person reads the above information on the protein needs and benefits of a high protein diet but remembers in the back of their mind another myth about high protein intakes. "I thought high protein diets are bad for the kidneys and will give you osteoporosis! " they exclaim with conviction and indignation. 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.

 

[sk*]

This trully is going to be a great debate ...

Thanks for joining in dc.

-sk

 

[wyld1g]

2thick, I wanna get back to the red meat thing for a sec. It would seem logical that since vegetarian's need protien sups because they don't eat red meat, would indicate a lack of the total protiens required or entire range of protiens rather, would be an indication that red meat is required in a diet in order to ingest the proper range of protiens. Hence, a diet of both veggies and red meat..what are your thoughts on this?

 

[revexrevex]

Can you please post full title of the research study?

 

[DOGGCRAPP]

from peter lemon interview: Your friend and sometime research partner Tarnopolsky, suggests that even higher amounts seem useful for elite weightlifters when he studied advanced lifters who were taking 2.2 to 3.5 protein grams per kilogram of bodyweight per day

But we have not done those types of studies. However, some of the studies from the former Soviet Union and Eastern Europe have shown some benefits from very high protein intakes.
MM: Just how high are we talking about?
Dr. Lemon: We're talking about going from 2 grams to over 3 grams. Some of these studies are not translated very well, and some are almost anecdotal in their style, so we don't know how accurate they are. But that's where a lot of the bodybuilders get their information, because that's where strength athletes were very, very successful

Doggcrapp:: Tarnopolsky has gone up and down with his protein recommendations--acknowledging and agreeing with the Russians and then agreeing with Peter Lemon at 1.8-2.0 gram per kilo-so I guess he cant make up his mind-but most studies are done on novice bodybuilders anyway(gee thats relative)

 

[JKerry]

Also, real food contains co-enzymes that help break down food and absorb the nutrients at a higher rate.

not true,

"some nutrition faddists fail to realize that most proteins are broken down to amino acids before absoprtion. they urge consumers to 'eat enzyme a. it will help you digest your food.' or 'don't eat food b. it contains enzyme c, which will digest cells in your body.' in erality, though, enzymes in foods are digested just as all proteins are. only the digestive enzymes, whose designe prevents them from being denatured or digested, can work in such an environment."

there's a little bit of "fluff" in the exert, but the point is made.

understanding normal and clinical nutrition, fifth edition

kerry

 

[2Thick]

not true,

"some nutrition faddists fail to realize that most proteins are broken down to amino acids before absoprtion. they urge consumers to 'eat enzyme a. it will help you digest your food.' or 'don't eat food b. it contains enzyme c, which will digest cells in your body.' in erality, though, enzymes in foods are digested just as all proteins are. only the digestive enzymes, whose designe prevents them from being denatured or digested, can work in such an environment."

there's a little bit of "fluff" in the exert, but the point is made.

understanding normal and clinical nutrition, fifth edition

kerry

I am talking about coenzymes (i.e. B6) that activate the enzyme, not the enzyme itself.

As a supposed nutrition major, you should know that.

Think and read before you post.

 

[DOGGCRAPP]

Common Myths
about Protein

by Bryan Haycock M.Sc., CSCS


Myth #1: High protein intakes will not affect muscle protein synthesis.

Fact: Greater availability of amino acids means more protein synthesis within muscle cells.1,2,3,4,5,6,7,8
I will concede that experiments have been performed that indicate that a lab animal can survive on a very limited protein intake assuming that fat and carbohydrate intake is adequate. Simply put, the body begins to reduce that amount of amino acid oxidation in order to spare nitrogen containing compounds. Yet can we really apply this kind of example to adult humans trying to build muscle? I think not.

When the body begins getting stingy with amino acids because of low protein intake, non essential functions, such as skeletal muscle protein synthesis, drop to minimal levels. Other functions within the body such as the immune system, which uses glutamine primarily of muscle origin for fuel, also begins to suffer.9


This cripples the body's ability to cope with the stress and tissue damage induced by intense training. Researchers even believe that currently recommended protein intakes may actually predispose people to illness because of the limited reserve of amino acids. Here's what they have to say about current recommendations for protein intake:

"...It seems reasonable to conclude that the lowered rate of whole-body and perhaps muscle protein turnover that appears to occur in healthy adult subjects when intakes of indispensable amino acids approximate the current international figures, would probably diminish the individuals capacity to withstand successfully a major stressful stimulus. Again, for those reasons, we view the significant reduction in the rate of body protein turnover in healthy adults, which permits them to more closely approach or even achieve amino acid balance at currently accepted amino acid requirement intakes, as an accommodation. Thus we further conclude that these international requirement intakes are probably not sufficient to maintain a desirable or adapted state."(Young VR., Marchini JS. Mechanisms and nutritional significance of metabolic responses to altered intakes of protein and amino acids, with reference to nutritional adaptation in humans. Am J Clin Nutr 1990;51:270-89) Emphasis added.

Research clearly shows that by increasing blood levels of amino acids you increase protein synthesis in skeletal muscle. It has also been shown that you can maintain a positive nitrogen balance for extended periods of time and that nitrogen accretion will tend to continue as long as protein intake is high.10 Clearly if you want to maximize your gains in the gym you gotta get more protein than the average Joe.

Myth #2: You can only assimilate 30 grams of protein at one sitting.


Fact: The body has the ability to digest and assimilate much more than 30 grams of protein from a single meal.

Speaking of high intakes of protein, people have been perpetuating the myth that you can only assimilate ~30 grams of protein at a time, making protein meals any greater than a 6 oz. chicken breast a waste. This is anything but true. For example, the digestibility of meat (i.e. beef, poultry, pork and fish) is about 97% efficient. If you eat 25 grams of beef, you will absorb into the blood stream 97% of the protein in that piece of meat. If, on the other hand, you eat a 10 oz steak containing about 60 grams of protein, you will again digest and absorb 97% of the protein. If you could only assimilate 30 grams of protein at a time, why would researchers be using in excess of 40 grams of protein to stimulate muscle growth?1

Critics of high protein intakes may try to point out that increased protein intake only leads to increased protein oxidation. This is true, nevertheless, some researchers speculate that this increase in protein oxidation following high protein intakes may initiate something they call the "anabolic drive".13 The anabolic drive is characterized by hyperaminoacidemia, an increase in both protein synthesis and breakdown with an overall positive nitrogen balance. In animals, there is a correspondent increase in anabolic hormones such as IGF-1 and GH. Though this response is difficult to identify in humans, an increase in lean tissue accretion does occur with exaggerated protein intakes.14,15

The take home message is that, if you are going to maximize muscle growth you have to minimize muscle loss, and maximize protein synthesis. Research clearly shows this is accomplished with heavy training, adequate calories, and very importantly high protein consumption. This means that meals containing more than 30 grams of protein will be the norm. Not to worry, all that protein will certainly be used effectively by the body.

Myth #3: Protein must be rapidly digested to build muscle.

Fact: Both rapidly and slowly digested proteins offer significant benefits to athletes.

Recent research has brought up the notion of "fast" and "slow" proteins.11 They are designated as such according to the rate at which they raise blood levels of amino acids after they are consumed. Whey protein for example is considered a fast protein and causes a rapid increase in amino acid levels. Casein on the other hand is considered a slow protein.

Both rapid and slow proteins offer benefits to someone trying to build muscle. Research has shown that proteins that enter the blood stream rapidly significantly increase protein synthesis. Proteins that enter the blood stream slowly have a pronounced effect on protein breakdown, significantly inhibiting it even at low quantities.

By using a combination of proteins that exhibit both fast and slow properties one should be able not only to jump-start protein uptake into muscle cells during a grueling workout, but also ensure that protein synthesis is jump started and that protein break down is kept at a minimum during the hours following their workout. Take the fast protein before training, and a slow protein after for maximum anabolic effect.

In summary, it is a mistake to say that a "fast" protein is better than a "slow" protein. Both types of protein should be used in strategic fashion to alter protein metabolism in favor of net protein deposition (i.e. muscle growth).


Myth #4: A protein must have added peptides of specific molecular weights to effectively build muscle.

Fact: The body's digestive tract makes its own variable molecular weight peptides from the whole proteins you eat.

As soon as protein hits the stomach it is attacked by powerful stomach acids. This acid, along with an enzyme called pepsin, serves to change or denature the proteins structure preparing it for further digestion in the small intestine. In the small intestine several other enzymes work to break down the protein into various molecular weight peptides and free amino acids. Each enzyme acts on a specific part of the amino acid chain cleaving it in the appropriate place. Whether you've just eaten a steak, scrambled eggs or a glass of whey protein, the end result of digestion is the same, a full spectrum of molecular weight peptides and a moderate amount of free amino acids perfectly suited for absorption into the body.

The small intestine has special transporters which actively pull peptides across the brush border membrane and into intestinal cells. All the various peptide transporters have yet to be clearly identified. As a result of these transporters, peptides can be actively absorbed faster than free amino acids. Within intestinal cells, peptides are further broken down into individual amino acids by enzymes called protease (prote = protein, ase = to split or cleave). It has been shown that a very small percent of digested peptides can enter the blood stream by squeezing between intestinal cells. Even though some peptides make it into the blood stream intact, they are quickly broken down by proteases on the surface of liver and muscle cells. If by some small chance peptides actually make it all the way into these cells, they are rapidly broken down by proteases within the cell.

So you see, all this talk about adding various molecular weight peptides simply means that they predigested an already easily digestible protein. This simply adds to the expense of manufacturing the protein. The added cost, of course, is passed on to the consumer.

References:

1. Tipton K., Ferrando A., Phillips S., Doyle, JR D., Wolfe R. Post exercise net protein synthesis in human muscle from orally administered amino acids. Am. J. Physiol. 276: E628-E634, 1999

2. Bennet, W. M., A. A. Connacher, C. M. Scrimgeour, and M. J. Rennie. The effect of amino-acid infusion on leg protein turnover assessed by L-[15N]phenylalanine and L-[1-13C]leucine exchange. Eur. J. Clin. Invest. 20: 37-46, 1989

3. Castellino, P., L. Luzi, D. C. Simonson, M. Haymond, and R. A. DeFronzo. Effect of insulin and plasma amino acid concentrations on leucine metabolism in man. J. Clin. Invest. 80: 1784-1793, 1987

4. Fryburg, D. A., L. A. Jahn, S. A. Hill, D. M. Oliveras, and E. J. Barrett. Insulin and insulin-like growth factor-I enhance human skeletal muscle protein anabolism during hyperaminoacidemia by different mechanisms. J. Clin. Invest. 96: 1722-1729, 1995

5. McNulty, P. H., L. H. Young, and E. J. Barrett. Response of rat heart and skeletal muscle protein in vivo to insulin and amino acid infusion. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E958-E965, 1993

6. Mosoni, L., M. Houlier, P. P. Mirand, G. Bayle, and J. Grizard. Effect of amino acids alone or with insulin on muscle and liver protein synthesis in adult and old rats. Am. J. Physiol. 264 (Endocrinol. Metab. 27): E614-E620, 1993

7. Newman, E., M. J. Heslin, R. F. Wolf, P. T. W. Pisters, and M. F. Brennan. The effect of systemic hyperinsulinemia with concomitant infusion of amino acids on skeletal muscle protein turnover in the human forearm. Metabolism 43: 70-78, 1994


8. Watt, P. W., M. E. Corbett, and M. J. Rennie. Stimulation of protein synthesis in pig skeletal muscle by infusion of amino acids during constant insulin availability. Am. J. Physiol. 263 (Endocrinol. Metab. 26): E453-E460, 1992

9. Newsholme, A.E., Parry-Billings M. Properties of glutamine release from muscle and its importance for the immune system. JPEN. 14 (4) supplement S63-67

10. Oddoye EA., Margen S. Nitrogen balance studies in humans: long-term effect of high nitrogen intake on nitrogen accretion. J Nutr 109 (3): 363-77

11. Boirie Y, Dangin M, Gachon P, Vasson M-P, Maubois J-L, and Beaufrère B. Slow and fast dietary proteins differently modulate postprandial protein accretion (amino acid turnover / postprandial protein anabolism / milk protein / stable isotopes) Proc. Natl. Acad. Sci. USA Vol. 94, pp. 14930-14935, December 1997

12. Sarwar G. The Protein Digestibility-Corrected Amino Acid Score method overestimates quality of proteins containing antinutritional factors and of poorly digestible proteins supplemented with limiting amino acids in rats. J. Nutr. 127: 758-764, 1997

13. Millward, D.J. Metabolic demands for amino acids and the human dietary requirement: Millward and Rivers (1988) revisited. J. Nutr. 128: 2563S-2576S, 1998

14. Fern EB, Bielinski RN, Schutz Y. Effects of exaggerated amino acid and protein supply in man. Experientia 1991 Feb 15;47(2):168 72

15. Dragan, GI., Vasiliu A., Georgescu E. Effect of increased supply of protein on elite weight-lifters. In:Milk Protein T.E. Galesloot and B.J. Tinbergen (Eds.). Wageningen The Netherlands: Pudoc, 1985, pp. 99-103

 

[revexrevex]

Question. This is a bit off topic, but I figure I might get an answer.

If a basic blood test is showing negative nitrogen balance, does it mean I do not have enough protein present in my system, or is it completely unrelated to the discussion?