Protein Absorption Question

Hi all! Disclaimer first:  I'm not a scientist nor a doctor nor a nutritionist, nor do I play one on TV.  However, I'm a medical librarian, and do literature searches for a living.  After hearing the "You can absorb 30 grams of protein at a time" statement, I set out to see where that information came from.  What I discovered is that it's a REALLY complicated question (no big surprise there, I guess!), and the answer is a major "It depends."  There have been some studies done on various kinds of proteins on people with NORMAL digestive systems, NOT bypass patients, so keep that information in mind! This information comes from an article entitled "A Review of Issues of Dietary Protein Intake in Humans" by Shane Bilsborough and Neil Mann, published in the International Journal of Sport Nutrition and Exercise Metabolism, 2006, volume 16, pp. 129-152.  (As you can guess from the title, the journal is one aiming more at body building and sports fitness, but it reviews articles from mainstream medical journals.)  The article includes a table of "Approximations of Amino Acid Absorptions from Different Protein Sources": Egg Protein Raw:  1.3 grams of protein per hour per kilogram of body weight Pea flour: 2.4 grams of protein per hour per kilogram of body weight Egg protein cooked: 2.8 grams of protein per hour per kilogram of body weight Pea flour: globulins & albumins:  3.4 grams of protein per hour per kilogram of body weight Milk protein: 3.5 grams of protein per hour per kilogram of body weight Soy protein isolate: 3.9 grams of protein per hour per kilogram of body weight Free AA: 4.3 grams of protein per hour per kilogram of body weight Casein isolate: 6.1 grams per hour per kilogram of body weight Free AA (same profile as casein): 7-7.5 grams per hour per kilogram of body weight Whey isolate: 8-10 grams per hour per kilogram of body weight The article doesn't give brand names or anything like that.  Because it's a review article, it has a lengthy bibliography (and the table I quote from above includes the number for the article the information came from).  Now, if I figure things correctly, at my weight (if I hadn't had bypass surgery), I could absorb over 600 grams of protein from whey isolate in an hour -- and that is a recipe for disaster, because there is definitely such thing as too much protein! So, that's what I've found.  If you want to see the article yourself, it's available free online: http://humankinetics.uwic.ac.uk/eJournalMedia/pdfs/5642.pdf And remember -- ALWAYS FOLLOW THE ADVICE OF YOUR DOCTOR AND NUTRITIONIST, NOT A LIBRARIAN ON A MESSAGE BOARD!!!! Hope this helps clear things up, at least a little! Lisa

Thank you Lisa, for finding confirmation of what I suspected.

LIsa, THANK YOU SO MUCH.  That is just the type of article I was  looking for.  I will read it asap.  It certainly indicates we can absorb quite a few grams of protein, epsecially in the pre-digested forms such as whey protein isolates.  Of course, I'm sure being gastric bypass individuals, we are different from the body builders.  But now I consider myself a "body building WLS hottie".  lol thank you, thank you, thank you, you rocking medical librarian you. Debra M. sipping her hot cocoa protein cup of heaven

Here is a link to a page that has some excellent Q&A about proteins, the different types and benefits for US.  Scroll down past the product information and then begin reading the question and answers part:  http://lifesourcelabs.com/protein.html  

I don't trust anything from someone trying to SELL the stuff, but that's me.  I like to see independant reports to back up what they say.

I'm with you on this one!  That goes for everything from protein supplements to vitamins to makeup for me!  :-)

Do you take into account that whey isolates and such are not digested and go direct to the blood stream? Protein is harmful to the kidneys and such if digested in the regular manner (foods). I would really like to see a study on WLS people (distal vs proximal) done on us to get a real true picture. But, our lab work shows the real picture in time.

 

Thanks for the info.

 

 

I haven't be able to find any articles on protein absorbtion in WLS folks -- and believe me, I've looked and looked and looked!  There is no doubt about the harm caused by too much protein which is why I said you should follow the advice of your doctor and nutritionist.  The fact that your body CAN absorb so much protein doesn't mean that it SHOULD.  In fact, it means to me that you should be careful not to overload since it can absorb that much. 

This is a topic I've researched since my surgery (12/05) and will continue to research (I do a weekly update for our surgeons here) so if an article on protein absorption in WLS folks comes available, I assure you I'll let everyone know!

Lisa

It certainly sounds like you're doing more research than me.  And believe me, I tried a lot in the beginning, but it is so frustrating coming up on only info from the sales end [that's why I appreciated your first post so much].  There is really more conjecture than fact floating around. 

Thanks again for your diligence!