HI HALL!
BCAAs share the same carrier in the gut and would be facing competitive antagonism therefore supplementation they have less effect on the MPS (Assuming it the Most Important amino acid is leucine) with a high concentration of isoleucine and valine.
My question is: The whey protein With a high amount of BCAA's (example, 10 g leucine / 100g, 6g valine / 100g, 6g isoleucine / 100g) cause a competitive antagonism leucine or only in the case of BCAAs with high concentration of Ile and Val?
In the case that the whey protein doesn't cause inhibition despite high concentrations in Ile and Val, why would it be?
THANKS :)
Great question, I've come across and asked this same question. If a true antagonism takes place in the gut lining receptors would we not see more deficiencies related to these amino acids in certain populations. I've come across papers that suggest the antagonism; however yet to see a paper showing a true Leu or Ile deficiency?
The majority (2/3) of amino acid absorption in the gut occurs by peptide transport (pept1) not free amino acids and there is no antagonism among the BCAA for uptake. Whey protein is rapidly digested and ~100% absorbed in any amount that I have seen tested. The L-transporter in muscle cells also appears to be a near equilibrium status with no significant gradient between IC and EC. There is some competition among LNAA for transport but mainly the BCAA to aromatic aa, and not among the BCAA.
The study by Churchward et al describe precisely this potential competitive antagonism between BCAA, so I got the idea that the higher the concentration of Ile and Val are more complicate things for leucine and therefore the MPS will be reduced. Subsequently Morton et al recommended "intact" protein instead purified combination of BCAA. Then you really will have less impact on the MPS the BCAA supplementation (with a ratio 2:1:1 or 4:1:1) compared to Whey + leu enrichment or BCAA supplement with low concentration of Ile, Val, and high concentration of Leu (ratio 8:1:1 or 12:1:1) or definitely no liability significant antagonism in the commercial BCAA supplements?
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@Donald K Layman I saw that into the enterocyt some peptide might still be broken down in AA's is that possible?
@Mat Jf I also came with this question. I thought it was a good question, and I think yours is excellent. All I can say it that the concept itself is merely a model. There is no view on how many transporters there really are. Asken Jeukendrup wrote about gut absorption (you might know this already because question is two years ago ofcourse). In this case 60 g of glucose and 30 g of fructose could be ingested.
Now if normal people it this they will be sick. Because this needs to be trained. Would an athlete also not train the gut, and the absorption of transporters? So much BCAA ingestion with much sport would upregelate transport.
So might increase of the ratio's not increase the transporters also?
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