Help Me: SN-2 Positioning

What the hell does this mean?

  • A lot. Let me help you.

    Votes: 1 16.7%
  • Absolutely nothing. Go to bed already.

    Votes: 2 33.3%
  • No idea. Let's figure this out.

    Votes: 3 50.0%

  • Total voters
    6

Geronimo

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May 11, 2020
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I'm having a difficult time figuring out how the sn-2 positioning of fatty acids works. What's the mechanism? What's the practical application? For instance, I've been using beef Tallow for its stearic acid and palmitic acid content, but I've read that over 50% of the fatty acids in the sn-2 position are oleic in tallow, and lard contains palmitic acid as the primary sn-2 fatty acid. And good luck finding out which position the acids are in for a stearic acid supplement. My questions are: what the hell does this mean? Does it matter?
 

Amazoniac

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- Would You Be Interested In A Choline Supplement? (within Spoiler)
- Why Ray Recommends Eating Lots Of Calcium

- Lipid digestion in stomach and small intestine: steps, enzymes, products

- Regioisomerism of Triacylglycerols in Lard, Tallow, Yolk, Chicken Skin, Palm Oil, Palm Olein, Palm Stearin, and a Transesterified Blend of Palm Stearin and Coconut Oil Analyzed by Tandem Mass Spectrometry

"There is a high variation in stereoisomers in oils and fats of different biological origin with typically strong species specificity."

"Lard is unique among animal depot fats, because it has a strong predominance of saturated fatty acids in the sn-2 position (1-5). In lard, most stearic acid is found in the sn-1 position, whereas position sn-3 is rich in oleic acid (2).

"In beef tallow and other bovine adipose tissues, nearly 50% of the fatty acids in the sn-2 position are oleic acid, whereas palmitic, stearic, and oleic acids are the major fatty acids in the sn-1/3 positions (6, 7). The positional distribution, although characteristic for each animal species, can be modified to some extent by feeding (6)."

"Very similar structures of TAGs have been found in chicken plasma, in ovarian follicles, and in eggs (3). In these fats, a high degree of asymmetry between positions sn-1 and sn-3 is found. Palmitic acid is mainly in the sn-1 position, whereas >60% of sn-2 fatty acids and sn-3 fatty acids are oleic acid. Linoleic acid predominates in the sn-2 position (3, 8-10). The positional distribution of fatty acids in hen’s egg TAGs is not affected by variation in the dietary fats of hens (9)."

"Seed oils tend to have polyunsaturated fatty acids in the sn-2 position, but relatively little difference can be found between the primary positions, although less abundant fatty acids are often concentrated in the sn-3 position. The 1,3-random-2-random distribution of fatty acids in seed oils is commonly accepted, even though this model should be regarded as an approximation (3). The absence of palmitate in the sn-2 position is characteristic of plant TAGs in general (11). In palm oil, oleic acid comprises >60% and linoleic acid >20% of the fatty acids in the sn-2 position. In the fractionation process the amount of palmitic acid in the sn-2 position reflects the changes in fatty acid composition so that the amount of palmitic acid in the sn-2 position is decreased in palm olein and increased in palm stearin when compared to palm oil (12)."

"In this study ammonia negative-ion collision-induced mass spectrometry (NICI-MS) was used to determine the molecular weight distributions of triacylglycerols of lard, tallow, yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend (82:18) of palm stearin and coconut oil. The fatty acids in each molecular weight species and the regioisomerism of these acids were determined from the collision activation spectra using a triple-quadrupole mass spectrometer. The method has been described previously and applied to, for example, seed oils and human milk fat (15-17)."
You'll find..

Table 2. Distribution of triglyceride molecules according to the 'sum of carbons from fatty acids' and 'total double-bond count'.
Table 3. Detailing the organization of selected triglycerides from Table 2.​
 
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SOMO

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Mar 27, 2018
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The real query is to what degree do sn-1 and sn-3 get incorporated into cell membranes and to what degree do sn-2 become prostaglandins/eicosanoids and for this, I fear we have no answers yet.

Could lard from corn/Pufa-reared porcines form less prostaglandins than palm-oil, chocolate/cocoa butter or suet? It is possible, but knowledge of the ultimate fate of the individual FAs on the triglyceride is lacking (perhaps it is just my knowledge on the subject that is lacking).
 
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Geronimo

Geronimo

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May 11, 2020
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The real query is to what degree do sn-1 and sn-3 get incorporated into cell membranes and to what degree do sn-2 become prostaglandins/eicosanoids and for this, I fear we have no answers yet.

Could lard from corn/Pufa-reared porcines form less prostaglandins than palm-oil, chocolate/cocoa butter or suet? It is possible, but knowledge of the ultimate fate of the individual FAs on the triglyceride is lacking (perhaps it is just my knowledge on the subject that is lacking).

I'm with you on this. If we can find a fat with mostly stearate and palmitate in the sn-2 position, it seems important. Unless, of course, sn-2 position of ingested fats doesn't correlate with sn-2 incorporation into tissues and cells. It SEEMS important for sure. I'd say lard seems to be in the lead so far?
 

Energizer

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Mar 3, 2013
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Rather than trying to wade through the muddy waters of obscure nutrition jargon, my little caveman brain prefers to just keep things simple. I see coconut oil, fully hydrogenated, and I buy it (0% polyunsaturated fatty acids). And butter mixed in with that for flavor. The best of both worlds.
 
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lilsticky

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Nov 27, 2019
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Jack kruse talked about this. He eats fish in order for the omega 3 to work properly, the algae they eat is sn1 and sn3 and the fish are needed to provide dha in the sn2 pos. Cows eating grass does the same thing
 

lilsticky

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I think this is something you would expect from a whole food like olives or coconut flesh. Not oils
 
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Geronimo

Geronimo

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Jack kruse talked about this. He eats fish in order for the omega 3 to work properly, the algae they eat is sn1 and sn3 and the fish are needed to provide dha in the sn2 pos. Cows eating grass does the same thing

Yeah my one time exposure to Jack Kruse was him talking about sn-2. I had no idea what he was talking about lol. I'm starting to think tallow and lard are really the best fats for human consumption, considering the evolution of human physiology alongside eating mostly ruminant meat. I know that reeks of paleo which is frowned upon here, but even tropical cultures have been eating pigs and other ruminants for a very long time. The moral of the story is: I don't know what's best among the best of fats, but we can certainly say the best are coconut, butter, lard and tallow. Hey! We should tell this Raymond Peet guy what I found out!
 

Mito

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Dec 10, 2016
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I'm having a difficult time figuring out how the sn-2 positioning of fatty acids works. What's the mechanism? What's the practical application? For instance, I've been using beef Tallow for its stearic acid and palmitic acid content, but I've read that over 50% of the fatty acids in the sn-2 position are oleic in tallow, and lard contains palmitic acid as the primary sn-2 fatty acid. And good luck finding out which position the acids are in for a stearic acid supplement. My questions are: what the hell does this mean? Does it matter?
“The shorter ones cannot occupy the sn-2 position of the phospholipid, and hence will not displace arachidonic acid without prior elongation. While it's true that palmitic acid is a membrane lipid, it is found exclusively in the sn-1 position. These positions aren't interchangeable, as the enzymes which act on them have specificity which is position-dependent. Phospholipase A₂, for example, is induced by cytokines such as interferon-γ and cleaves membrane phospholipids exclusively from the sn-2 position. Since this position is enriched in arachidonic acid—in most Americans—the release of interferon-γ after immunogenic stimulation (i.e. infection, gluten pep-tide) leads to prostaglandin formation, a product ensured by the concomitant induction of cyclooxygenase-2 by cytokines which generally accompany the interferon-γ. There is nothing wrong with myristic and palmitic acids, yet they simply aren't found consistently 'protective' nearly to the extent that stearic acid is. I think this could best be explained by its lone ability to occupy the phospholipid sn-2 position among the common saturated fatty acids (the mysterious C∶20 lipid is rare, yet does exist.)”
Cacao Butter: Strong Anti-cortisol, Anti-anxiety Effects
 

SOMO

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Mar 27, 2018
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1,094
Rather than trying to wade through the muddy waters of obscure nutrition jargon, my little caveman brain prefers to just keep things simple. I see coconut oil, fully hydrogenated, and I buy it (0% polyunsaturated fatty acids). And butter mixed in with that for flavor. The best of both worlds.

Not really relevant for those of us that still consume meat and eggs - the positioning of the triglyceride FAs is particularly relevant when it comes to intake of animal foods.

I abstain from pork most of the time, but if I didn’t have to, I would much rather not because pork is delicious and tastes better than beef or oysters.
 

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