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Low-PDCAAS proteins as a substitute for protein restriction?


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" Wheat gluten is the plant-based protein with the lowest PDCAAS value at just 25% (Table 1). "

from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723444/

^hmm, this makes me want to eat more gluten! low protein digestibility means you feel full after eating them *AND* they don't stimulate mTOR as much

same with peanut protein powder a la https://www.amazon.com/PB2-Performance-Peanut-Protein-Powder/dp/B07Y5H8K5D

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Proline-rich stretches on protein sequences typically reduce the flexibility of the protein chain and are known for their high resistance against peptidase hydrolysis. Gluten proteins, for example, are characterized by high proline levels, which is one of the reasons for its limited digestibility. Tight protein folding or protein aggregation generally restrict access to the peptide chain, and, hence, slow down hydrolysis. Factors affecting protein solubility also influence protein digestibility. Martinez-Velasco and colleagues [34], while studying the digestibility of proteins in maize tortillas during storage, described a negative correlation between protein digestibility and the level of secondary beta-conformations (i.e., beta-sheet and beta-turn conformations) [34]. The limited digestibility of these secondary structures was ascribed to their high hydrophobicity. Both beta-sheet and beta-turn structures were shown to play a crucial role in the formation of a viscoelastic wheat flour dough [35]. At a higher structural level, crosslinking within and between single proteins drastically affects protein digestibility. Geiger and Harris [36] studied the digestibility of wool protein by pepsin. Wool protein is characterised by a dense network structure of peptide chains that are joined through disulfide crosslinks. The reduction of these disulfide bridges, followed by subsequent (partial) reoxidation, showed that the digestibility of those samples with low crosslinking degree was much higher than those proteins that were crosslinked to a greater extent. Upon breadmaking, disulifide bond formation plays a crucial role to dough viscoelasticity and gas retention capacity and final bread quality [37,38].

 

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The most well-described antinutritional factors found in plants (and (pseudo)cereals) that limit protein digestibility are protease inhibitors (e.g., trypsin and chymotrypsin inhibitors), tannins and phytates [8,39,40]. Haemagglutinins/lectins in legumes and cereals, glucosinolates in mustard and canola protein products, gossypol in cottonseed protein products, saponins in legumes, oats and tea, and uricogenic nucleic acid bases in yeast protein products are a few other examples [8,41]. Lectins, i.e., noncatalytic sugar-binding proteins, interfere with protein hydrolysis and are themselves known for their high resistance to proteolysis and stability over a wide pH range

 

Edited by InquilineKea
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NOW IF YOU WANT TO KNOW THE REAL REASON WHY RAW EGGS > COOKED EGGS..

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6617089/

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In terms of protein digestibility, very early studies indicated that raw egg white is highly indigestible and causes serious gastrointestinal discomfort upon consumption [48]. Upon processing (in this case heating), the digestibility of egg white proteins considerably increased. Early studies pointed to an anti-tryptic factor or special chemical constitution of the proteins, hampering protein digestibility. Of all the different egg white protein constituents present, the albumin fraction was identified as the highly indigestible component. Raw yolk, in contrast, is well-digested and utilized and if gastrointestinal discomfort arises upon consumption of raw yolk, it is often ascribed to the high fat content of this fraction [48]. Later studies indeed confirmed that the true ileal digestibility of cooked and raw egg proteins was very different, i.e., about 90% vs. 50%, respectively [49,50]. In vitro testing with specific peptidases indicated that ovalbumin in raw egg white was only slightly or even not digested, while heat coagulated egg white proteins were much more susceptible to digestion by pepsin [50].

 

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And finally, plant proteins tends to be digested less efficiently than animal proteins; animal protein is usually at least 90% available, whereas plant protein may be only about 80% available [43,44]. Thus, the disparities in bioavailable Met content between plant and animal products are actually understated by Table 1.
An additional factor may also be at work. Plant proteins tend to be relatively rich in glycine [45], which can acts as a functional Met antagonist by serving as a methyl group acceptor in a reaction cat-alyzed by glycine N-methlytransferase; this enzyme transfers a methyl group from S-adenosylmethionine to the amine group of glycine [46]. In rodents, a high-Met diet tends to elevate circulating cholesterol levels; this effect is antagonized by a concurrent high intake of glycine [47]. Indeed, the Met/glycine ratio of the diet is a determinant of plasma cholesterol in rodents [47,48].

(from https://pubmed.ncbi.nlm.nih.gov/18789600/ )

Edited by InquilineKea
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  • 1 month later...
Jason Avent
Low T4 also makes you sluggish. Be careful what you wish for.
 
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Kenneth Bruskiewicz
Jason Avent Tradeoff for longevity: do you want live long or burn bright?
 
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Jason Avent
Kenneth Bruskiewicz I think it is possible to have the best of both worlds. The important thing is to have some metric of your productivity and intelligence. I write a lot, so it is easy for me to see when I am not doing as well one day compared to another. Methionine restriction seems to hit many of the longevity goals without slowing metabolism to a crawl. I would rather be a healthy, vibrant person who lives to 100 compared to the emaciated person who makes it to 120 'existing'.
 
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Alex K. Chen
Ya just be vegan. But you can also do a MEK inhibitor
 
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Jason Avent
Alex K. Chen Vegan with tons of lentils and raw vegetables is really amazing. I use Beet juice pigment (betalains) as my MEK inhibitor.
and betalain as an mTOR inhibitor
 
 
 
 
 
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Alex K. Chen
is beet juice that much of a MEK inhibitor? btw that's amazing - you know A LOT of chemistry, gawd, we should def talk more
 
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Alex K. Chen
don't the lentils have protein in them? methionine in the protein all adds up
 
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Jason Avent
Lentils have a very low level of methionine in their proteins. Like, freakishly low. I have a theory that deficits in sulfur amino acids like this are an adaptation for the plant to grow in low-sulfur soils. The great part of this is that the benefits pass on to you. You don't have to cut out 'protein' what everyone talks about when they say, "Not a complete protein" really has to do with oddball deficits like methionine being low, but everything else is up there. I want collagen to be made, so I take NAC, and glycine along with lots of lentils and mung beans. My cancer cells will have to work for it. If they want methionine, then they are going to have to make their own.
 
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Jason Avent
I haven't dug into the reasoning on this page, but it appears that the methionine in lentils is only 50% bioavailable. From a molecular biology point of view, the methionine left after a selection against methionine-rich proteins should be ones tightly bound in the protein structure. Not sure if the bioavailability of all methionine is low, but it would be cool if the biochemist's intuition about rare materials being used in critical junctions pans out, we could actually see this in the protein structures. I would predict no methionine on 'loop' structures of proteins.
"Notice how the methionine content of lentil protein is quite low relative to EAA requirements. Also, less than 50% of the methionine in lentils is actually absorbed by the body. We can surmise that, although lentil protein is theoretically a complete protein, in practice it is deficient in the essential amino acid methionine."
and a chart!
 
May be an image of ‎text that says '‎25.0 ש % 10.0 5.0 20.0 15.0 MMH His Iso Leu Lys Met Phe Thr Trp Val Lentils EAA Requirements Profile of EAAs in lentils as compared to the profile of EAA requirements. His: histadine, Iso: isoleucine; eu: leucine, Lys: lysine; Met: methionine; Phe: phenylalanine; Thr: threonine; Trp: tryptophan; Val: valine.‎'‎
 
 
 
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– The health effects of different proteins are largely mediated by their amino acid profiles. Some amino acids such as glycine and histidine might decrease low-grade inflammation, while high intake of methionine might be harmful. These effects have been mostly studied in rodents, and currently there seems to be quite little human research on the subject.
– Examples of protein sources with a good glycine:methionine ratio would include: gelatin, scallop, fish, potatoes, lentils and beans. Many popular animal foods such as milk, eggs and meat tend to have quite a poor ratio of these amino acids. The amino acid profiles of plant proteins might explain some of the beneficial effects of vegetarian diets.
– Amino acids are not the only factor affecting the biological effects of dietary protein. In some cases, hydrolyzed protein (peptide) might be more suitable for weight control than intact protein, and the effect might be mediated by gastrointestinal hormones. Casein might decrease the harmful effects of a high-fat diet by decreasing fat absorption in the intestines.

– Some studies have been showing that individuals with insulin resistance might have lower plasma levels of glycine, histidine, and taurine than healthy people. Because this “deficiency” of anti-inflammatory amino acids might lead to more inflammation, it is possible that people with insulin resistance would benefit most from the amino acid supplementation.[15]

 

 

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https://febs.onlinelibrary.wiley.com/doi/10.1111/febs.16292

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It is interesting to note that although increasing the amount of fat in the diet, while keeping the same amount of protein, showed a trend in increasing SASP expression, the effect was less noticeable when the protein content was low in the diet (Fig. 2 and Table 1).

 

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