That’s great. So, off the top of my head, one I would focus on is our underappreciation of the relevance of the hormone insulin. Earlier we were talking about this caloric paradigm of health and obesity and metabolic-related diseases, which a lot of diseases fall into, including the ones we spoke about minutes ago or at least mentioned.
Insulin tells the body what to do with energy. That’s its theme. There are several ways that insulin has been underappreciated, if not overtly ignored. One of them is the role of insulin in telling the body to store energy, where it is absolutely impossible for the human body to store or gain fat unless the hormone insulin is elevated.
It cannot happen. I know that’s a bold thing I’m saying, but I’m saying it. You cannot make human fat tissue, or any animal actually, expand unless insulin is elevated, full stop. It is absolutely impossible.
Now again, I’m not saying energy load or calorie number doesn’t matter. It is. You have to have energy there, but unless the insulin is up to tell the body to store that energy, it can’t. It just can’t happen.
That’s one thing that I know is very debated, so I’m trying to be very deliberate and cautious in exactly what I’m saying. You can’t make the human body store energy unless insulin is up.
On the lighter side of this — very much of interest I would imagine to the BarBend end audience — would be the role of insulin in protein anabolism in the muscle. That is also very much misunderstood. Insulin does not promote muscle protein synthesis in the muscle. That is not true, but insulin does defend muscle protein. That’s an important distinction.
Rather than considering insulin as an anabolic hormone at the muscle — which it isn’t — it’s more accurate to consider insulin as an anti-catabolic signal at the muscle. It will defend muscle protein.
This has been very well-documented in in vivo studies of living, breathing humans, where they’re spiking up the insulin and detecting that it is in no way promoting an enhanced muscle protein synthesis. It’s been done at the very granular level of individual muscle cells.
When you are incubating muscle cells with the best amino acids, and that’s — at a narrower level we’d say branched-chain amino acids, at an even narrower level we’d say leucine — that is going to promote muscle protein synthesis, just the presence of those amino acids. Insulin does not accelerate that process, but it defends the process.
That’s so important because as people are progressing towards insulin resistance, and the majority of adults in the United States and many many other countries are. In fact, they’re well past that point, the average adult. The muscle is one of the primary tissues that becomes insulin-resistant. That could be why in type 2 diabetes, we noticed this elevation in amino acids in the blood, because it’s coming from the muscle.
Because the muscles become insulin-resistant, insulin can’t defend the muscle protein. Now, the muscle is just experiencing a higher degree of protein catabolism. It’s leaking out its amino acids into the bloodstream, so you’ll have higher levels of amino acids in the blood because insulin…The muscles become insulin-resistant and now we’ve lost the anti-catabolic effect of insulin.
Another kind of bit of a myth or misinformation. One last thing I’ll say, David, to shift the topic, and I won’t go very far with it, is the misunderstanding of the nutrient lactate. People will say lactic acid, which doesn’t exist in mammals. It’s not this protonated form. It’s lactate. It’s in no way contributing to acidemia or acidosis, or the burning of the muscle when it’s intensely working.
It’s lactate. Lactate is a totally unappreciated fuel. The brain will use lactate as a fuel. The other cells with mitochondria, which is virtually every cell in the body, except red blood cells can pull in lactate and burn it in the mitochondria like it would ketones for fuel. Again, the brain uses lactate very well.
The liver takes up most of the lactate to turn it back into glucose through this wonderful biochemical process that’s called the Cori cycle, C-O-R-I. Lactate is a very misunderstood nutrient. It’s maligned, but not fairly.