Italians eat a lot of wheat

[Ducky]

"That opioid peptides have a numbing effect?"

I thought they get broken down and denatured with heat like proteins thus losing their numbing effects.

[Ducky]

I searched and haven't found any scientific paper on this issue.

So if anybody has one I would like to see evidence that:

1. opioid peptides don't get denatured by heat

2. opioid peptides survive the digesting process and keep their functionality

For example peptide hormones like insulin and growth hormone have to be injected in the blood because taken orally they are digested thus have no effects.

Unlike many medicines, insulin currently cannot be taken orally because, like nearly all other proteins introduced into the gastrointestinal tract, it is reduced to fragments (even single amino acid components), whereupon all activity is lost.

So that's very much possible that opioid peptides end up the same way.

[Oscar]

Meisel H, FitzGerald RJ., 2000: http://www.ncbi.nlm.nih.gov/pubmed/11242443
Kitts DD, Weiler K., 2003: http://www.ncbi.nlm.nih.gov/pubmed/12769739 Peptides with opioid activities are derived from wheat gluten or casein, following digestion with pepsin. [and more]

[Ducky]

And how can we read the original article , experience? It's just an abstract.

[Ducky]

In order for exorphins to function as opioid peptides
in the central nervous system in vivo, they must
(1) be produced in the gastrointestinal tract,
(2) survive degradation by intestinal proteases,
(3) be absorbed, without degradation, into the bloodstream,
(4) cross the blood-brain barrier and thereby reach central opiate receptors, and
(5) interact as opiates with these receptors.

There is already a problem with stage 3:

The opioid food peptides have lengths of typically 4-8 amino acids. The body's own opioids are generally much longer.

Dietary proteins are, with very few exceptions, not absorbed. Rather, they must be digested into amino acids or di- and tripeptides first.

There is virtually no absorption of peptides longer than four amino acids. However, there is abundant absorption of di- and tripeptides in the small intestine.

http://www.vivo.colostate.edu/hbooks/pa ... acids.html

[RRM]

I would like to see evidence that:
1. opioid peptides don't get denatured by heat

Opioid peptides are very short chains of amino acids.
Denaturation is about the unfolding of the 3-dimensional structure of proteins, not about changing the amino acid sequence.
Particularly large proteins have 3-dimensional structures, simply because they are so long.
Large proteins contain hundreds (to up to thousands) of linked amino acids.

opioid peptides survive the digesting process and keep their functionality

Yes.
That is the case because they are so short.
They are contained in large proteins that are split in smaller peptides by enzymes.
Theyare relatively resistant to the intestinal proteinases trypsin and
chymotrypsin.Zioudrou C et al

insulin and growth hormone have to be injected in the blood because taken orally they are digested thus have no effects.

Human insulin contains 51 amino acids, and a clearly 3-dimensional structure (partly due to the disulfide bonds).
Human growth hormone contains 191 amino acids.

There is virtually no absorption of peptides longer than four amino acids. However, there is abundant absorption of di- and tripeptides in the small intestine.

These 2 opioid peptides contain only four amino acids:
Glycine-Tyrosine-Tyrosine-Proline
Tyrosine-Glycine-Glycine-Tryptophane

[Ducky]

These 2 opioid peptides contain only four amino acids:
Glycine-Tyrosine-Tyrosine-Proline
Tyrosine-Glycine-Glycine-Tryptophane

And do you know their name and what are they doing? Because not every opioid peptides have the same effects. Are they absorbed through the intestines?

The research on opioid peptides is very young and scarce and there are very few in vivo experiments on animals, let alone humans.

Just because it works in vitro it doesnt mean it works in vivo. That is a hasty generalization to make.

[Ducky]

These 2 opioid peptides contain only four amino acids:
Glycine-Tyrosine-Tyrosine-Proline
Tyrosine-Glycine-Glycine-Tryptophane

And most of the OPs are longer than 4. So that only reduces their numbers a big deal.

Wikipedia says that even those that pass through will be further broken down.

Most peptides longer than four amino acids are not absorbed. Absorption into the intestinal absorptive cells is not the end. There, most of the peptides are broken into single amino acids.

[RRM]

most of the OPs are longer than 4. So that only reduces their numbers a big deal.

That is a hasty generalization to make.
We first need to know how much of the other OP are actually absorbed.
Two very active OP are only 5 amino acids long.

Wikipedia says that even those that pass through will be further broken down.

The key word is: "most".
Do they effect us, yes or no?
That is the question.

And do you know their name and what are they doing?

Usually they go by their amino acid sequence: GTTP and TGGT, or GlyTyrTyrPro and TyrGlyGlyTry,
but they are also referred to as Gluten Exorphin A4 and B4.S Fukodome et al
They are released from wheat gluten by pepsin and/or trypsin.
They have opioid-like activity by competitive binding to opioid receptor sites (in rat brain tissue).FR Huebner et al
The most active peptides are from the gliadin fraction of the gluten complex.

The research on opioid peptides is very young and scarce and there are very few in vivo experiments on animals, let alone humans.
Just because it works in vitro it doesnt mean it works in vivo. That is a hasty generalization to make.

They (digested gluten) work in vivo in dogs.V Schusdziarra et al
Several studies suggested a relationship with autism and schizophrenia.Calassi C et al, probably involving immune system factors.Severance EG et al Free full text
A 2014 meta-analysis (of 12 scientific studies) found that 5 biomarkers of gluten sensitivity were found to be significantly elevated in patients with psychoses. Lachance LR et al

[Ducky]

Several studies suggested a relationship with autism and schizophrenia.Calassi C et al, probably involving immune system factors.Severance EG et al Free full text

And other studies haven't found any differences.

[RRM]

This says it all:
A 2014 meta-analysis (of 12 scientific studies) found that 5 biomarkers of gluten sensitivity were found to be significantly elevated in patients with psychoses. Lachance LR et al

[Ducky]

No, not really. All it says is that gluten has an effect on people who are already ill. Just like in the case of celiac disease.

So it doesn't prove anything from our point of view.

[RRM]

It shows the effects of gluten.
In the brain.
In disorders such as autism the effect is much greater due to increased permeability of the intestines.
So that the effects of opioid peptides are much greater.
Equally so, the urine of autists contains more opioid peptides from milk.
The urine of healthy people also contains such opioid peptides, but significantly lower levels.
Lower, but not absent.

[Ducky]

It's hard to tell, apparently they are not free to read. Have you bought them?

[RRM]

What is hard to tell?
That the urine of healthy subjects also contains opioid peptides?
Glumorphin B5 consists of five amino acids.
"we can demonstrate that overloading a normal person with gluten and gliadin for three days resulted in finding Glumorphin B5 in urine."
Reichelt KL et al
The above is from a FREE full text.