Rapeseed oil for weight loss: Norwitz vs Goodrich (eventually, scroll down if bored by the very long Protons preamble)

Rats fed a diet with 40% of calories from rapeseed oil are slim.

Rapeseed oil‑rich diet alters hepatic mitochondrial membrane lipid composition and disrupts bioenergetics

"Rats assigned to the modified diet showed a slight delay in growth (Fig. S1, left), probably related to a lower food intake (Fig. S1, right)."

Like this

That's correct, feeding a 40% fat diet where the fat is rapeseed oil produces less weight gain compared to standard carpinabag chow. Because the rats had, and I quote, "a lower food intake". This translates, for less mealy mouthed people, as "the rats were less hungry while still eating to satiety". However at week two, when weight was already down, the rats were actually eating *more* calories of the rapeseed oil diet, compared to the chow fed group. Uncoupling. Decreased insulin signalling.

Aside: they also note:

"The only significant [gross pathological] alteration observed in rats submitted to the 20 % rapeseed oil diet was a decrease in the [hepatic] triglyceride content (56 ± 7.1 mg/dL as compared to 137 ± 29.5 mg/dL for control rats) after 33 days of treatment."

Yes, you read that correctly, rapeseed oil is protective against the fatty liver which is routinely induced by chow with 7% of calories as PUFA, mostly LA. That's a huge drop in hepatic trigs. Anyone want to cure NAFLD?

End aside.

Now, from the Protons point of view there are two ways of avoiding obesity (or NAFLD). You can

a) get your ROS in to the range equivalent of treating an adipocyte with H2O2 at around ~3-4mmol/l, ie employ physiological insulin resistance generated by saturated fats during the peak absorptive phase after a meal. My approach. It works.

or

b) reduce your ROS generation to a level too low for peak insulin signalling, say to the equivalent of ~0.01-0.03mmol of H2O2.

That means uncoupling.

PUFA, especially linoleic acid, fail to generate adequate ROS via Dave Speijer's F:N ratio hypothesis which is the basic underpinning of Protons. So they are obesogenic.

However, they are also uncoupling.

Which effect predominates determines whether the PUFA based diet you have chosen to eat is obesogenic or not. How much PUFA, which species, whether they are mitochondrially targeted. Linoleic acid (LA) at 35% of calories is uncoupling and will normalise the weight of a lard fed mouse. Alpha linoleic acid (ALA) will do the same, but studies tend to use high dose rates. People love all-or-nothing models. So simple to secure funding.

Hypolipidemic Activity of Peony Seed Oil Rich in α-Linolenic, is Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid β-Oxidation

More translation: "Mediated Through Inhibition of Lipogenesis and Upregulation of Fatty Acid β-Oxidation" actually translates as "reduced insulin signalling". If you can measure virtually everything but have no hypothesis to hang you facts on, you'll get nowhere.

At what level of intake this effect kicks in is difficult to determine but it will undoubtedly be lower for ALA than for LA.

Now we can look at the current study in those terms.

Do the liver mitochondria uncouple?

Yes, and no.

The numbers are best for experiments using succinate to feed the mitochondrial preparations. With a priming dose of succinate followed by a flood of ADP the mitochondrial run flat out (state 3 respiration).

Here there is a slightly *lower* O2 consumption in the mitochondria from rapeseed oil fed rats, a paradox:

That doesn't look like uncoupling.

We have a large supply of metabolic substrate and a large supply of ADP to allow ATP-synthase to turn but still, in supposedly uncoupled mitochondria, oxygen consumption is reduced. The same happens when feeding with glutamate-malate to input at complex I but something went wrong with these data at the week 22 mark. Overall it doesn't look like these mitochondrial are uncoupled on either substrate.

Next we can look at what happens when the added ADP has run out (state 4 respiration). Now ATP-synthase cannot turn because there is no ADP available, so any oxygen consumption must be via uncoupling. That's exactly what we see. There is now also plenty of intra-mitochondrial ATP to allow uncoupling protein activation. So yes, uncoupling happens in this state:

Equally unexpected for already uncoupled mitochondrial is the effect of full uncoupling with FCCP. Here we again have paradoxically reduced oxygen consumption in the uncoupled mitochondrial preparations from the rapeseed oil fed rats.

So the question is why should supposedly pre-uncoupled mitochondrial have lower oxygen consumptions than either fully uncoupled mitochondria or mitochondria running at full chat? Whether you "feed" your preparation with a complex I input or a complex II input?

There is nothing wrong with these mitochondria. Bioenergetic are *not* disrupted, as suggested by the title of the paper. Let's dig deeper.

What is happening is that the study is taking mitochondria from fat-adapted rats and feeding them on either a complex I input or a complex II input. Fatty acids, even LA, make significant use of electron transporting flavoprotein (ETF) dehydrogenase as their input to the CoQ couple. Mitochondria adapt their electron transport chains to the substrates available. If mitochondria from rats fed 40% of calories from fat are significantly dependent on mtETFdh for input to the CoQ couple, and have down regulated both complexes I and II, then feeding the preparation on substrates specifically aimed at complex I or II will obviously produce sub-maximal oxygen consumption. Which is what happens under either state 3 respiration or FCCP uncoupling.

Under the "tickover" conditions of state 4 respiration the uncoupling from PUFA shows clearly.

Obviously, to restore visibly normal mitochondrial function, what's needed is a supply of reduced ETF to use as a substrate for mtETFdh. As supplied by beta oxidation. Sadly you can't just buy reduced electron transporting flavoprotein from Sigma Aldridge, so you end up with artifactual mitochondrial "dysfunction".

Another aside: that is exactly what is happening here too

Prolonged Fasting Identifies Skeletal Muscle Mitochondrial Dysfunction as Consequence Rather Than Cause of Human Insulin Resistance

discussed here

Will fasting destroy your mitochondria? (No).

It *appears* as if mitochondria adapted to high input from mtETFdh are dysfunctional if you fail to supply them with adequate electron transporting flavoprotein! The study did try to get around this by using octanoyl-carnitine (50μmol/l) as a lipid input to generate reduced ETF but clearly even 50μmol/l of palmitate will provide twice the ETF of 50μmol/l octanoate and the chaps in the study were running total FFAs of up to 3000μmol/l, not 50μmol/l, at the time that the muscle biopsies were taken. Utilising 3000μmol/l of FFAs provides a lot of ETF. So "dysfunction" is really an experimental artefact induced by lack of metabolic substrate for mtETFdh (secondary to using an homeopathic level of octanoate in this case or no mtETFdh substrate at all in most studies). 

End aside.

Okay. Protons says that reducing the mitochondrial membrane potential reduces superoxide production (and its derivative H2O2) to levels which do not promote activation of the insulin signalling cascade.

Delta psi is definitely reduced by the rapeseed oil feeding. These are the values for delta psi of a fully charged membrane using glutamate-malate (succinate is the same) but before any ADP has been added, ie this is as high as the membrane potential can get with the substrate supplied (the graph is deliberately upside down as delta psi is always negative):

The membrane potential drops by less in the mitochondria from rapeseed oil fed rats when ADP is supplied but it is still always lower that for the control rats.

Is this reflected in lower production of H2O2?

Yes:

The only unanswered question is how does a production rate of H2O2 of just over 2000pmol/mg prot/15mins in uncoupled mitochondria fed succinate through complex II compare to just over 3000pmol/mg protein/15mins in the normally coupled mitochondria? And how do these relate to the steady state exposure to H2O2 used in

Evidence for Electron Transfer Reactions Involved in the Cu2+-dependent Thiol Activation of Fat Cell Glucose Utilization

to generate this graph

This we can't answer directly. The fact that the rats fed rapeseed oil were lighter than those fed chow suggests, to me, that there was less insulin signalling going on in the adipocytes of the slim rats.

People may disagree.

That's fine, just it makes sense to me.

But: Is it Good or Bad to run your (slim) metabolism on uncoupling levels of PUFA when compared to running on insulin resisting saturated fat?

Ah, now that's a question. There are suggestions as to the correct answer.

Running your metabolism on a mix of LA and ALA which allows uncoupling to a normal or a slightly slim bodyweight might make you look good. Without having listened to any of the podcasts of Nick Norwitz (he's clearly a bright guy) I can easily accept he's fully able to maintain a slim bodyform, combined with high ketone levels, using PUFA, even if he doesn't mind getting sunburned occasionally as a trade off.

Running your metabolism predominantly on fat while avoiding PUFA also works, looking at Tucker Goodrich here. Normal bodyweight, minimal risk of sunburn.

So here's the decider, and it's not sunburn:

Who is most at risk of pancreatitis? I know, I know, none of us will get pancreatitis. But we might. You can stack the deck. This is Nick's pancreas on PUFA:

Distinctive roles of unsaturated and saturated fatty acids in hyperlipidemic pancreatitis

"At sufficiently high concentrations, unsaturated fatty acids were able to induce acinar cells injury and promote the development of pancreatitis." [Not my typo].

Well, look what happens when you emphasise PUFA for maximum ketosis:

Early- and late-onset complications of the ketogenic diet for intractable epilepsy

I'm sure this won't happen and Nick will be fine. But, if it does happen, pancreatitis is a really fun condition to have (not) and, if you get a good dose of it, you are heading for the ITU for quite a long stay. Will you live or die? That's largely dependent on whether you develop acute (some say adult) respiratory distress syndrome (ARDS). While people have tried treating this with a combined heart-lung transplant, it's better avoided if you want to survive.

You can pretty well predict who will develop ARDS as they come in to the ITU by simply counting the double bonds in their plasma free fatty acids.

An increase in serum C18 unsaturated free fatty acids as a predictor of the development of acute respiratory distress syndrome

"The calculated ratios of serum free fatty acids (ie., the ratio of C18 unsaturated fatty acids linoleate and oleate to fully saturated palmitate, C16:0) increased and predicted the development of ARDS in at-risk patients."

Now, I have fundamental ideas about choice of lipid sources for weight normalisation. Those ideas are compatible both with the choices made by Tucker and those made by Nick. Both are correct in their diametrically opposed choices. They are both correct for bodyweight. But there are nuances. I like nuances.

One choice is more likely to lead to the ITU and to the development of ARDS than the other.

My advice is to NEVER need to go to the ITU and DO NOT develop ARDS.

There are some real lifestyle choices which influence these outcomes. Rapeseed oil for weight loss works. It also raises the number of double bonds in pretty much all of your tissues.

Choose wisely.

Peter

Addendum. BTW just to clarify: You don't actually need pancreatitis to develop ARDS. It's a generic route to death in the ITU. Simple severe trauma will do the job. The PUFA are still what influence whether you live or die.