Thursday, May 28, 2020

Blood "energy" content

"One-liner" post. This is exciting (picked up on twitter from Mike Eades):

Effects of dietary carbohydrate content on circulating metabolic fuel availability in the postprandial state

It's Ludwig's group. I've skim read but not looked at the detail. I like what I see.

Over the last year or so I've ventured in to the morass of older papers about the CNS response to infusion of various metabolic substrates where you get bogged down in the various neural groups which respond in various ways to high vs low glucose etc. It's messy and it's rare for people to have asked the questions in quite the way I might have phrased them.

Eventually I simply started adding up the energy content of "blood" in various states, especially under extended fasting when hunger becomes blunted. Being me I tended to add them up in terms of how much NADH and FADH2 might be available. I kept getting pushed towards the idea that hunger might be a simple matter of the energy content of the blood supplying the hypothalamus. Clearly that is one core thing that the CNS monitors (using ROS of course).

Could hunger be this simple?

Okay, there is also clearly a neural input (think hepatic FFA infusion via the portal vein suppressing food intake) but ultimately if the brain is being perfused with too few calories, it is going to do anything it can to make you eat. The classic is reactive hypoglycaemia or insulin induced hunger where I suspect the problem is (in myself in pre low carb days) not absolute hypoglycaemia (I could get this at BG around 4.5mmol/l) but the accompanying low FFA availability giving low brain stem energy availability. But of course measuring FFAs is not as simple as measuring glucose...

Anyway, it's fantastic to see some serious researchers looking at the concept of blood energy content. They will have to add the Protons concept eventually, to explain why things happen as they do, but they're on an exciting trajectory.

Peter

16 comments:

Eric said...

Energy, (protein) and micronutrients, in my eyes atleast...

This could be tested, but how is another question (with real food, for me atleast). How does one remove the protein from beef, for instance, while retaining all the other stuff? Butter is easy to add.

ctviggen said...

Peter, I think the link might be broken (at least for me). These might be it.

PDF:

https://www.researchgate.net/publication/236040291_Effects_of_Diet_Composition_on_Postprandial_Energy_Availability_during_Weight_Loss_Maintenance/link/023308180cf292cfa7c05550/download

Text:

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3590159/

Bob Kaplan said...

@ctviggen - No, I think it's this paper (May 27, 2020).

Click on the "PDF" link and it pops in your browser. I think sometimes the PDF link that's created from it "expires" after a short period of time.

Peter said...

I've changed the link in the post to point to the abstract, which Mike used. As you say Bob, just click on the pdf link. The 2013 paper looks interesting too...

Peter

Unknown said...

This energy that you speak of; where is it coming from? The food we eat seems to be the answer, but that food is made up solely of electrons, protons and neutrons. These objects are and will remain identical to all the other ones in the universe. They’re immutable. They cannot be drained of energy (however that might work) and retain their identity. We ingest them and after they are put through the processes of our system they emerge as they were. Not drained of any energy whatsoever. Given this, how do you explain the heat you are radiating at this moment? It looks like an energy-for-free scenario to me. You and most everyone else is missing something. Actually, the something.

Gyan said...

Electrons don't have same energy. There are energy levels in molecules so organisms move electrons from higher energy levels to lower levels.
Protons and neutrons are all probably irrelevant here

Unknown said...

@Gyan Where does the energy in the energy levels come from? It has to have a source. What gets drained? And all electrons are identical; otherwise the universe wouldn't work as it does.

LeenaS said...

Unknown: Not really. In nuclear power plant energy is produced without changing electrons, protons or neutrons. There energy is released when some bonds between them are broken, i.e. breaking atoms just a tiny bit. In the case of food that every single organism uses, we are only using the chemical energy of molecular bonds between atoms. The same energy is released in fire, which turns wood or whatever into carbon dioxide and water... and warmth. : )

Unknown said...

@ LeenaS What is the nature of these bonds? What are they made of? Some special chargeable bond-only particles or are they some sort of ethereal energy (whence the energy?) bonds forcibly holding molecules together?

So you’re saying that the bonds are broken (which would necessitate another mystery force stronger than the bond) and then subsequently the broken bonds do more work? Where does the energy that the bonds somehow store come from? What do they drain to get the energy?

Fires are powered by broken chemical bonds? Who knew. Again, there has to be an ultimate source for all this energy. What is it?

cavenewt said...

Peter, is this one of the previous messy studies? I collected it a couple of years ago and never got around to sending it on to you. It's too far over my head to know if it's useful or not.

"UCP2 Regulates Mitochondrial Fission and Ventromedial Nucleus Control of Glucose Responsiveness"

https://www.cell.com/cell/fulltext/S0092-8674(16)30112-X

LeenaS said...

@Unknown: Welcome to quantum physics.
Matter and energy are intercheangable, so that one can turn into the other :)

Gyan said...

Energy is not a thing but merely an accounting variable introduced in physics to understand the phenomena.

It has no meaning outside the formalism of physics.

Alex said...
This comment has been removed by the author.
Kajus said...

https://cholesterolcode.com/extra-virgin-olive-oil-vs-butter-experiment-design/
28 days of liquid diet experimenting.

Peter said...

Kajus,

That will be an interesting one!

Peter

cavenewt said...

Kajus and Peter, a July 10 update on the EVOO/butter liquid diet experiment:

"Cholesterol, Citizen Science Foundation, Experiments by Dave

"EVOOvsButter Experiment Paused

"The Extra Virgin Olive Oil vs Butter Experiment had to be aborted. I was feeling a number of symptoms I assume to be related to electrolyte issues on Day 2 and some further issues on Day 4 and 5 that may or may not be electrolyte related. I may detail the symptoms more in a later write up (members can hear me discuss it on the MMM from this last Monday)."

https://cholesterolcode.com/evoovsbutter-pause-lmhr-study-update-energy-model-paper/