Protein Digestion/Absorption was Re: GI index

[Guest guest]

> From: power7777us@...

> Subject: Re: GI index

>

> There is no way your body is absorbing 50 grams of protein at one time,

unless

>

> 1. you have a lot of muscle

> 2. you are consuming a predigested hydrolysate

> 3. you are eating a post workout meal.

>

> If you are eating 50 grams of protein at every meal, then a lot of it is

getting used for fuel, which produces the waste product of ammonia, which in

turn catabolizes muscle tissue.

:

The research would argue against some of the points you make (up above). The

digestive limit of protein has been estimated at somewhere between 320-480 g

of protein (using baked lean beef) over the course of 8 hours (Free &

Leonards, 1944, J Lab Clin Med, v29, p963). This is from a 1944 study that

has yet to be replicated with other types of proteins and/or other

populations. The practical tolerance test for protein digestion is to keep

eating protein until diarrhea, excessive flatulence, or some other GI

disturbance develops. We had resistance-trained guys ingest up to 105 g of

TwinLab's Whey Fuel in one sitting with no observable signs of GI distress.

While this would hardly suffice for a publication, I think it can still be

useful as a guide.

The absorptive capacity for protein digestive products in the lumen can vary

depending on the amounts of amino acids, peptides, and whole proteins. This

is further complicated by the form of amino acids (ie D vs. L), chain length

of the peptides, type of proteins (ie whey vs. casein vs. gelatin vs. soy

vs. beef vs. fish), and presence of other materials in the lumen (ie fat,

carbohydrates, non-digestible products, enzyme inhibitors, etc), which can

create nutrient interactions. For convenience protein digestion/absorption

is usually studied after an over night fast and usually a small amount of a

single protein is administered. It is difficult to apply this type of

research to people that are eating all kinds of food products throughout the

day. On top of that, add into the mix, the fact that they may be more

physically active, eating during the night (and minimizing the length of the

overnight fast), ingesting large quantities of alcohol, etc.

The utilization of protein is a different matter. I suspect this is what you

were referring to in your original post. It seems there would be an upper

limit to how much muscle mass one could add in a day and working backwards

from there it would seem that there should be an upper limit to the

utilization of amino acids from dietary protein for protein synthesis. I am

not sure at this point where the " weak link " in the whole process is.

Recently I have been more interested in stimulating protein synthesis with

as few calories as possible (to allow people to add muscle while minimizing

fat gain). The following combination is what I have come up with based upon

interviews with several researchers and recent publications from R Wolfe's

lab and A ' lab. I have not yet approached this from the perspective

of what is the upper limit of protein synthesis. Perhaps someone else can

add their thoughts here.

I originally posted this on the Strength List:

The best formula I have come up with from my reviews of the literature and

interviews with the scientists doing the research, is the following:

Histidine 650 mg

Isoleucine 720 mg

Leucine 1800 mg

Lysine 930 mg

Methionine 190 mg

Phenylalanine 930 mg

Threonine 880 mg

Valine 1080 mg

Taurine 1000 mg

Glutamine 1000 mg

Sucrose/Dextrose 35 - 40 g

The amino acids above would be consumed either in free form or peptide

fashion with table sugar or dextrose. The above combination would elevate

protein synthesis by 400% or more. I have to point out the above formula is

a combination of work from multiple labs (not my own lab). There is no

single study that has studied the exact ratio above. I calculated it from my

discussions with multiple investigators. The above would be ingested 10

minutes before training and again immediately after. The idea is to elevate

protein synthesis with as few calories as possible while supplying an

abundance of amino acids. The above mixture would provide roughly 188 - 220

Calories. I have used this mixture with myself and some of our clients.

Based upon the limited experience I have with this mixture so far, it seems

to assist with adding on muscle while minimizing fat gains. If you do try

it, please take some measurements and before after photos, so you can

determine for yourself if it is useful or not. I would be interested in the

responses that people have. By the way you could add 5 g of creatine to the

post-workout mixture.

Tom

Incledon, MS, RD, LD/N, NSCA-CPT, CSCS

Human Performance Specialists, Inc.

619 NW 90th Terrace

Plantation, FL 33324