Ep. 308: All About Amino Acids

In this episode, Stacy and Sarah talk about amino acid supplementation, empty stomaches and how your supplements compete for the attention of protein transports like they're hailing cabs in the big city!
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The Paleo View (TPV), Episode 308:  All About Amino Acids
Intro (0:00)
News and Views (0:40)
It is almost our 6-year podcast-iversary!
We are recording in advance this week because Sarah will be gallivanting around Canada soon.
Most all of Sarah's family lives there, and she hasn't been back to visit in two years.
She is very excited to have a vacation and visit family!

Sarah is excited about this week's topic- she did a lot of research and "nerding out."
We got a lot of great feedback on last week's show about Collagen.
This week's show is a great sister show to that topic.


Listener Question from Tess:
"I have heard people talk about amino acid competition, is this is a thing I should keep in mind? I bring it up because I eat lots of bone broth, collagen, eat meat and also take amino acids as supplements (l-glutamine and l-tyrosine). I started melting my brain about trying to take these all separate from one another, but does it matter? I would love to wash my l-tyrosine down with my collagen water in the morning, then support my gut health all day by drinking little bits of l-glutamine with or without meals! Thank for for the show, and I’m not just saying that because I want to suck up to you and get my question answered!!! I truly appreciate the sensible, practical info you both put out. I’m the type of person who really likes to know the WHY!!!"
Protein Digestion
Occurs in the stomach and first section of the small intestine.
This process is driven by hydrochloric acid.
Three main enzymes break food proteins into polypeptides.
Pepsin, Trypsin, Chymotrypsin.

Polypeptides are then broken down into peptides and amino acids by peptidase enzymes.
Exopeptidases and Dipeptidases.


About 30% of protein is absorbed as peptides, not individual amino acids.
These peptides are endocytosed or hydrolyzed inside enterocytes.

About 70% of protein is absorbed as amino acids.
In the digestive tract are 5 main families of amino acid transporters.
Divided by the types/properties of the amino acids they transport.
Neutral amino acid transporters transport: alanine, valine, leucine, methionine, phenylalanine, tyrosine, isoleucine, asparagine, threonine, glycine, proline, histidine, serine, glutamine, cysteine, tryptophan.
Different members of transporter families have higher affinity for specific amino acids.
For example, B0AT1 neutral amino acid transporter transports L-leucine, L-methionine, L-isoleucine, L-valine before it will transport L-asparagine, L-phenylalanine, L-alanine, L-serine before it will transport L-threonine, glycine, L-proline.

Cationic/Basic amino acid and cysteine transporters transport: lysine, arginine, histidine, cysteine.
Anionic/Acidic amino acid transporters transport: aspartic acid, glutamic acid.
Imino acid and glycine transporters transport: proline, hydroxyproline, glycine.
beta-Amino acid and taurine transporters transport: beta-alanine, taurine, betaine.

Generally, there are multiple pathways for any given amino acid.
Amino acids compete for binding with other high-affinity amino acids for each specific transporter.

The transporter system is extremely complex.
The body may be able to detect which amino acids are available and which the body needs, in order to prioritize amino acids.


Generally, 90% of protein we eat is digested and absorbed.
10% will pass through to the large intestine, where it may be digested by bacteria.

Low protein diets cause the body to up-regulate transporters.
Typically 1.3-10 grams per hour of amino acids can be absorbed.
If you eat a complete protein, you don't need to worry about amino acid content.

Is there a need for amino acid supplementation?
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