It's an interesting paradox to think about. As occasionally happens I found a non related paper which gives some suggestion of the mechanism. Here it is:
Characterizing the effects of saturated fatty acids on insulin signaling and ceramide and diacylglycerol accumulation in 3T3-L1 adipocytes and C2C12 myotubes
The paper uses adipocyte-like 3T3-L1 cells or muscle-like C2C12 myotubes. The 3T3-L1 cells might be worth another post in future, today is about the myotubes.
They looked at many things, but most interesting are the data on the ability of insulin to promote the storage of glucose in glycogen granules. I, being me, would look at this as a surrogate for un-measured lipid storage as lipid droplets in muscle cells. One of the cardinal rules of ectopic lipid deposition research is to never, ever suggest that myocyte lipid droplets might be enlarged by insulin signalling. They will be. Just like glycogen granules are enlarged by insulin.
So, practicalities. The myotubes were prepared in "low glucose" DMEM which is probably code for 5mmol/l, ie a normal physiological glucose concentration. To this medium was added a fatty acid at 0.75mmol/l, ie moderate fasting levels. Cells were incubated for 16 hours and then treated with supra-maximal insulin.
They noted that elevated pure palmitate is utterly harmless to cells in culture with normal glucose levels:
"Under these conditions, no signs of cell death were observed"
which certainly is not the case using 25mmol/l of glucose!
Here are the gels they obtained:
The top row, highlighted in red, is demonstrating the presence of phosphorylated (activated) Akt, a core insulin signalling step. We are comparing P-Akt under insulin and 5mmol/l glucose with that under insulin and 5mmol/l glucose plus 0.75mmol/l palmitate. It's clear that insulin signalling is markedly blunted by palmitate. If we look at the dashed oval we can see that the P-Akt band under oleate is comparable to that of the control.
The same applies to the level of phosphorylated glycogen synthase kinase 3 beta, a key enzyme in activating glycogen formation and outlined in blue. P-MAPK is irrelevant today but, again, might be interesting in the future.
Convincingly, palmitate causes insulin resistance and oleate doesn't. Bear in mind that this is a highly constrained experiment to make a specific point. These is no mention of ROS generation but it is worth looking at this from the Protons/ROS viewpoint.
Palmitate has an FADH2:NADH ratio of 0.484
Oleate has an F:N ratio of 0.457
In this experiment conditions are carefully controlled to give us an all or nothing response, almost like switch. The switch trips somewhere between an F:N of 0.484 and 0.457. Insulin resistant vs insulin sensitive. No double bonds vs one double bond.
It is possible to adjust the F:N ratio by smaller amounts than by adding a double bond simply by altering the length of a saturated fat. If we consider myristic acid the F:N ratio is 0.482 and for lauric acid it is 0.478.
The paper went on to look at insulin signalling using these fats and here are the gels they obtained:
At the extreme left is the control without insulin, next is control with supra-maximal insulin but no fatty acid, then rest of the bands have the indicated fatty acids added, all at 0.75mmol/l. I've put in the red line to divide insulin sensitive from insulin resistant results. Everything to the left of the line causes no insulin resistance, to the right significant insulin resistance. The switch is between myritic acid and palmitic acid, F:N 0.482 and 0.484.
I would expect C10 capric acid to be insulin signal facilitating and probably C8 caprylic acid too, although its strongly ketogenic effect and partial conversion to palmitate might make that less predictable.
Coconut oil is primarily medium chain triglycerides with F:N ratios on the insulin sensitising side of the switch. Formulating a high fat diet out of insulin sensitising fats combined with an insulogenic carbohydrate load seems like a good recipe for obesity.
It's always worth reiterating that there is no "switch" as such, there is a general integration of information about energy status and demand using ROS which can be pushed towards lipid storage or use depending on particular inputs. The F:N ratio looks like a switch in a very simple model asking a very simple yes-no question. But that's still useful information for understanding the Surwit diet.
Peter
But Kitava?
ReplyDeleteCoconut plus yam but no obesity.
And again I advert to special risk of consuming fat and carb in equal proportion by energy.
Whether this risk is shared by ghee plus carb diet. Here in old tim, obesity used to be limited to people not restricted in calories and having plenty of ghee and sugar
That is very precisely callibrated, so clear a signal.
ReplyDeleteThe Surwit diet - if you swapped the 58% coconut fat calories of D12331 out for palmitate would it be less obesefying given that carbs are 25% of calories split evenly between sucrose and maltodextrin? I'll bet the rats love it. A favourite treat in the schoolyard used to be chocolate crackles made from Cocoa-pops held together with Copha ie hydrogenated coconut oil melted, mixed in and set solid.
Gyan, excellent, lots to think about. One of the joys of Hyperlipid is pondering the paradoxes. Happily not all answers are available immediately. And sucrose is very interesting, very poorly understood stuff.
ReplyDeletePeter
Pass, yes, I wouldn't expect it to be obesogenic. I have been skirting around my poor understanding of fructose metabolism for many years.
ReplyDeletePeter
Oh, and if you substituted olive oil for the hydrogenated coconut oil I'd expect it to be obesogenic too, even with LA at around 4% of calories. It would start to approach the macros of the obesogenic diet fed to the db/db mice in Valerie Reeves' PhD, when stearate didn't induce obesity.
ReplyDeletePeter
Interesting that as a switch there is little difference between pure palmitic and pure stearic acid. Right now the keto/ROS world is loving stearic acid. In a mixed fatty acid diet, is the weighted average the important thing? In which case bolstering the stearic would give a boost to the ratio average to something above the "switch". Perhaps the question is too obvious to ask, but hey, I am asking it anyway. The reason is that adding stearic to ghee has become a thing, but the result can be waxy, so some have taken to adding in MCT oil to soften things up. I had to wonder whether they were basically negating the benefits of the stearic acid.
ReplyDeleteRichard, yes, I view weighted average as a crude approximation to what the front end of the ETC senses and integrates. I also think that there are layers and layers of signalling laid on top of the ROS signal, so evolution might have produced a more switch like effect compared to the graduated effect of unmodified F:N ratios...
ReplyDeletePeter
Richard, I've done the same: add a bit of MCT oil. Even with this, ghee/stearic acid gets waxy.
ReplyDeleteAt home, I started gathering the melting points of the fats, in order to ascertain whether I could use something like a sous vide to "guestimate" saturated fat content.
I started doing this when I bought low PUFA pork from Fire in a Bottle and cooked ground pork. I drained the "liquid" into a glass jar, took a shower, came back, and it was solid (and I mean SOLID) at room temp.
I can't unsee this. So, when I take normal bacon out of the fridge, and the fat is still mushy at fridge temp, I have a hard time eating it.
I made duck and left the rendered fat out overnight. Still liquid the next morning. Tossed it.
I put store-bought lard, the fat from the low-PUFA pork, Brad's stearic acid, and tallow from suet into clear glass jars and put them into the sous vide. I then went from room temp to 130F or so. The stearic acid never got near melting, but the tallow, fat, and lard finally did melt, the lard the earliest of the 3.
Unfortunately, the fat from the pork was so white that I had a hard time determining when it melted, and I had the jars buried under a brick. I couldn't feel the fat in them.
The idea was to see if I could apply this to other fats. For instance, I buy chickens from a local farm. Could I use this technique to compare store-bought with farm-bought chickens? Tried to do so, but could not get enough fat from individual chickens to compare.
It could be nice to have coconut or the like be something else to eat, though. Trying to get palmitic and stearic acids at a high level means there's not a lot to eat, really, especially if you try to avoid dairy. I'm getting tired of eating cacao butter.
ctviggen, that's a great testimonial for Brad's pork, thanks.
ReplyDelete"Trying to get palmitic and stearic acids at a high level means there's not a lot to eat, really, especially if you try to avoid dairy. I'm getting tired of eating cacao butter."
Rather than deal with waxy straight stearic acid I've also been using cacao butter for quite a while now. I do a stirfry most nights with beef and a small amount of various vegetables. I start out with a combination of cocoa butter, tallow, and butter or maybe some coconut oil to sauté in. It would be nice to feel comfortable with occasional pork again — I'll revisit Brad's offerings.
Peter, thanks. And to cavenewt and cfviggen, my own "stearic strategy" has been a little different. I bought a big bag of the pure stuff granulated. Tried combining with my own clarified-from-grassfed butter but it just sullied that great taste and made it too waxy. So now its full fat yoghurt or sour cream, just stir in a tablespoon of the stearic, add a teaspoon of good honey and I have a slightly crunchy desert. Unmelted, the stearic doesn't affect the flavour and the texture is not bad. As my main other foods are grass-fed beef and lamb, I think I am getting the ratios needed without becoming obsessive about measurement. Gotta have me some eggs too, a pity they run a bit high on the linoleic acid but two or three shouldn't be too much. First Peter, then Tucker Goodrich, Brad Marshall, and Chris Knobbe have made me a serious LA-phobe, with shout out to the Pauls Saladino and Mason. I love the work all these guys are doing but Hyperlipid was the foundation for all of them.
ReplyDelete"First Peter, then Tucker Goodrich, Brad Marshall, and Chris Knobbe have made me a serious LA-phobe, with shout out to the Pauls Saladino and Mason. I love the work all these guys are doing but Hyperlipid was the foundation for all of them."
ReplyDeleteMy experience exactly.
I feel like I've wandered into a meeting of pufaholics anonymous, although I am one too. David Gillespie's book " Toxic Oil" was what steered me away from seed oils, I'd never been a fan of margarine though. It just tastes awful. Gillespie's book was around 2013, his earlier book was "Sweet Poison" about sugar from 2008. Because of Gillespie I discovered Peter+Hyperlipid and all the pennies started dropping.
ReplyDeleteNo-one mentioning lamb? I'd prefer lamb over pork any day. I have just discovered that grass fed lamb is amongst the highest animal sources of ALA. Throw out the sardines and chew on a lamb chop.
I know lamb is expensive in some places, fortunately not where I live and there are lots of alternative fatty cuts eg " flaps". It used to be the case here that you could have any meat you wanted so long as it was lamb. (To misquote Henry Ford)
What seems to be lacking from the markets unless you have a friendly small country butcher, is mutton. Nice well developed older sheep with a good gamey taste and lots of fat.
I often get the best fatty cuts of lamb from the refrigerated pet food section of the supermarket. Still perfectly edible but just unloved and cheap. That's also where they keep the hearts, beef bones etc.
Woof!
Gillespie is not a biochemist but he writes in your face text that cuts through. This topic needs a few propagandists to counter the status quo. I bought my copy of his book in a supermarket which is splendidly ironic. It's the type of book you can secretly leave on other people's coffee tables when you visit and it might do some good.
ReplyDeletehttps://books.google.com.au/books/about/Toxic_Oil.html?id=LYv9vID8l9MC&printsec=frontcover&source=kp_read_button&newbks=1&newbks_redir=1&redir_esc=y
Sucrose/fructose is still a big problem imo. I am uncertain that a diet with 12.5% sucrose and 12.5% glucose is not fattening. Also I look back on my family history of what we now call type 2 diabetes: aunty, grandma, grt grandpa, gt uncle, gt gt grandma - they were mostly sheep and dairy farm people and seed oils weren't on the menu at all for them but sugar certainly was back to the times when sugar started to be cheaply available. I remember the horribly sweetened peach and melon jam that my grandma used to make. It made your teeth hurt and developed a sugary crust in the jar very quickly. She would spread it on 'pikelets', small pancakes also full of sugar. Everything had sugar in it.
The first 20 kilos I lost came from cutting out lots of sugary foods and fruit plus other starches. Low carb before I knew the term. Inevitably that means not eating junk food with its generous portions of h-h-pufa but I was cooking with lots of that so ... Cutting out the oils and going totally animal took care of the next few kilos. Other improvements are ongoing. There's no going back.
Passthecream: PUFAholics Anonymous is brilliant.
ReplyDeleteDang, my grocery store doesn't have a refrigerated pet food section. I believe you are in Australia where sheep would be much more common than here in the US. In addition to your vastly more interesting collection of various creepy-crawlies.
I get lamb from a cool-and-groovy online grassfed supplier (yes, expensive, so mostly I get tallow and some other odds and ends). But I just bought a lamb for one of my neighbors to raise — he's doing it for several friends — and I'm going to be sure to ask for not only my lamb's bones, fat, and organs, but those of any of the other participants who don't want those piecesparts. The hardest part will be resisting walking past and making friends with the future chops.
Dietarily speaking "Sugar is the low hanging fruit"
ReplyDelete:))
"not only my lamb's bones, fat, and organs, but those of any of the other participants"
ReplyDeleteIs that legal where you are now?
Passthecream I wonder if linoleic acid versus fructose is a based on a one-cause fallacy. In both cases the standard diet includes far more of each than would be evolutionarily normal, so each alone may cause issues. Even if LA is perhaps emerging as the greater evil, this would not exonerate sugar. For the trifecta, ultra-processed carbs. Basically a donut is the perfect food to promote if you are a cardiac surgeon who needs to upgrade your Beemer soon.
ReplyDeleteNow for real perfection, you just cannot beat a good NZ or Australian lamb chop. Or five or six...
Obviously no such thing as a single cause except maybe cyanide or pianos. But without carbs on the glucose axis ( glucose, maltodextrin, general starches) there won't be much insulin generated so perhaps insulin and other anabolics are a type of root cause. Linoleic acid causes a swag of different issues due to its inherently dangerous properties but without excess insulin not so many of those are obesity and hunger related.
ReplyDeleteFructose is another whole branch of study. It doesn't generate much insulin but neither is it controlled by it. It has a similar sort of disconnect from the usual processes as with linoleate. It's food, it will keep you alive, but there's a price to pay for it.
"Is that legal where you are now?"
ReplyDeleteTook me a while! An excellent example of how lack of an apostrophe could lead to cannibalism.
The conclusion regarding coconut is surprising also in connection with almost universal appreciation of coconut in Keto community as precisely anti-obesogenic and indeed slimming.
ReplyDeletePerhaps consuming coconuts while slightly increasing insulin signaling replace consumption of carbs so ultimately leading to less insulin signaling.
Gyan coconut oil also has the distinction of being very low in linoleic acid (2%)
ReplyDeletePeople in the keto community are not going to be eating any carbs worth counting. So it's a moot point really. They won't be producing insulin.
ReplyDeleteScfa in coconut oil give rise to ketones directly ( in the liver?), I don't know what effect insulin has on that process. That is different to fat burning/ketosis where a low systemic insulin level lets that take place widely.
ReplyDeleteIn the absence of insulin even a high intake of pufa can be burned as fuel so not really a problem. Not that I'd want to do that. What was brilliant in the experiment that Peter wrote about here is that glucose was held at a physiological norm and insulin was added while the fat type varied, the chain length. It throws the spotlight specifically on the f:n ratio. But this experiment was in vitro whereas in vivo the insulin would increase in response to an increase in glucose levels. How the mitochondria respond to that insulin depends on the f:n ratio of available fatty acids.
Now I need to track down whether there was much sucrose or fructose in the high fat chow in that Reeves PhD. At this point I'll gamble on there being not much, and that it contsined mostly starchy carbs therefore a glucose related input.
Would the potato diet be more effective if the small amount of added olive oil was replaced by stearate? Olive oil has plenty of C18 oleic altho it is mufa of course.
What's the rule about pufa and mufa vs f:n ratio? Is it that they behave like fats with a chain length up to the first kink and not beyond?
"What's the rule about pufa and mufa vs f:n ratio? Is it that they behave like fats with a chain length up to the first kink and not beyond?"
ReplyDeleteThat's what I remember. I once read a blog post, can't remember where, about how, during processing of fats, pairs of carbons are snipped off until a double bond is reached, at which point the process stops.
Thanks.
ReplyDeleteAs far as I can work out Reeves used a chow base of diet TD. 2918 which us an irradiated version of TD. 2018 (Teklad/Enviho) which then had the fat content manipulated. There are only corn wheat and soy products providing carbs in these diets, no sucrose and no fructose.
I think that was her big mistake, right there. How embarrassing it must have been to show that stearic acid prevents weight gain while oleic acid causes fatty liver
And full kudos to Peter of course for building this amazingly consistent view of metabolism viz Protons etc with all the trimmings. I feel that finally, I almost get it.
ReplyDeleteI am a perennial undergraduate though so ... ... ...
cave, I think oleic is good in combination with stearic/palmitic to give a “normal” F:N ratio. The more double bonds in the mix the higher the stearic needs to go to compensate. But adding a second double bond drops the F:N ratio much more than converting from palmitate to stearate increases it. But currently it looks like the best option.
ReplyDeletePass, when you go to the literature it’s only caprylate which is ketogenic. Hence the comment it might buck the pattern.
Eric, carnivore Edibles… sounds interesting to me
Peter
A quick search for "sources of caprylic acid" returns thousands of hits from the vendor's of nostrums, it's all the rage, including the amusingly titled "neuro octane" which is 100% caprylic. Many of the conditions it's alleged to heal look like the side effects of chronic hyperglycaemia so obviously there are better ways to fix those problems.
ReplyDeleteBut I do enjoy a tasty bit of goat cheese now and then.
If you need a hit of confirmation bias for this post by way of a human RCT, here it is
ReplyDeleteSmall Amounts of Dietary Medium-Chain Fatty Acids Protect Against Insulin Resistance During Caloric Excess in Humans
https://diabetes.diabetesjournals.org/content/70/1/91
Finally they get this HFD diet composition business right.
Bloody hell George, you sure know how to make a guy happy!
ReplyDeletePeter
Peter, you recently linked this paper "Fructose metabolism as a common evolutionary pathway" etc. By Johnson et Al.
ReplyDeleteWhich was fascinating!
In general there's some controversy, probably due to underpowered studies as to whether any benefit of cutting sucrose/fructose intake is merely a subset of carb restriction or something different. The varying combinations are often not well isolated and explored. But there are significant differences in the effects of glucose versus fructose as outlined in that Johnson paper and I think some of them can be linked interestingly to the details of this myotube/adipocyte paper.
(In a round about way.)
First the fats.
" Short- and medium-chain fatty acids do not require the carnitine shuttle for mitochondrial transport. Octanoate, but not palmitate, (eight- and 16-carbon saturated fatty acids) may pass the mt-membranes,"
( From https://www.bioblast.at/index.php/Fatty_acid_oxidation )
There's eg the caprylate right there, passing in directly. And some others. (Where does it cut off though, at what chain length?)
The carnitine shuttle is regulated in part by malonyl CoA
"One of the most common regulation systems of carnitine acyltransferases involves inhibition by malonyl-CoA, an intermediate in the synthesis of fatty acids. Malonyl-CoA inhibits long-chain carnitine acyltransferase activity"
( from https://proteopedia.org/wiki/index.php/Carnitine_acetyltransferase )
Tying it back to fructose:
https://pubmed.ncbi.nlm.nih.gov/31577934/
"Dietary sugars, fructose and glucose, promote hepatic de novo lipogenesis and modify the effects of a high-fat diet (HFD) on the development of insulin resistance. Here, we show that fructose and glucose supplementation of an HFD exert divergent effects on hepatic mitochondrial function and fatty acid oxidation. This is mediated via three different nodes of regulation, including differential effects on malonyl-CoA levels," etc.
Another related paper from the same group:
https://pubmed.ncbi.nlm.nih.gov/28972537/
Divergent effects of glucose and fructose on hepatic lipogenesis and insulin signaling
"In chow-fed mice, there was no major physiological difference between fructose and glucose supplementation. On the other hand, mice on HFD supplemented with fructose developed more pronounced obesity, glucose intolerance, and hepatomegaly as compared to glucose-supplemented HFD mice, despite similar caloric intake."
"... fructose is a component of dietary sugar that is distinctively associated with poor metabolic outcomes, whereas increased glucose intake may be protective. "
So, fructose "leads to the accumulation of malonyl CoA" which would down-regulate the carnitine shuttle which blocks entry to the longer chain fats thereby having a modulatory effect on RET levels and insulin resistance similar to that from pufa. In my understanding of the Protons view of L.U.E. anyway. Conditions apply.
Pass, there's an awful lot going on in the fructose paper and I've not really had time to go in to it in detain. The rest of your thought train is looking good...
ReplyDeletePeter
It is a multifaceted overview with good references to follow up. It all takes time. Fructose pops up in complex interactions in unexpected places - causes uric acid, stimulates vasopressin, can be diverted into fat production and into glucose production and boosts fat storage etc. It is a potent survival food for hard times and if you want to prepare for a long cold winter you'd better get plenty of good fat and as much fruit as you can find. Isn't it funny how a bear likes honey?
ReplyDeleteAs above with those mice, in normal times if you don't eat much fat the fructose won't fatten you any more than the potatoes will and conversely if you don't eat much fructose neither will sat-fat and potatoes but if you live on those good fries and cola watch out!