So who cares?
Apparently at least one person, who continues to find what I’ve learned about the anabolic role of insulin with respect to muscle to be downright objectionable.
And thus I came back to my computer after the weekend to find a couple more posts registering this person’s objections, not to mention her mischaracterizations of John Berardi & of what I wrote about his approach.
A definition of insulin from The American Heritage® Stedman’s Medical Dictionary, 2nd Edition (2004):
insulin: 1. A polypeptide hormone that is secreted by the islets of Langerhans, helps regulate the metabolism of carbohydrates and fats, especially the conversion of glucose to glycogen, and promotes protein synthesis and the formation and storage of neutral lipids.
Promoting protein synthesis is anabolic. So is “the formation and storage of neutral lipids.”
The same dictionary gives the definition of catabolism as follows:
catabolism: the metabolic breakdown of complex molecules into simpler ones, often resulting in a release of energy.
But it’s not good or healthy to have too much insulin in your blood. No indeed, nor did I ever suggest that it was. Too much insulin leads to insulin resistance & promotes obesity, because of course insulin is anabolic with respect to adipose tissue (body fat) too.
But I was surprised when insulin’s anabolic properties became such a bone of contention on the Insulin Resistance list: when I first mentioned insulin as anabolic for protein (muscle) as well as fat, I thought I was just discussing a fact well known to science & medicine that I hadn’t known before. Having someone insist that, no — contrary to what is said by science or medicine or numerous research reports in medical journals available for anyone’s persusal at PubMed — insulin is “catabolic,” has been rather like to having someone insist that no, water is in fact not wet.
The source that I happened to learn from about insulin as a muscle-promoting hormone happened to be that of someone who specializes particularly in nutrition for athletes — John Berardi, Ph.D. in exercise biology & nutrient biochemistry. His credentials can be read here. He’s far from ignorant when it comes to matters of nutrition; on the contrary, he consults to or actually designs nutritional programs for numerous athletic teams & individual athletes (as well as lots of sedentary individuals) because what he says works.
I’m not an athlete, just a 47-year-old insulin resistant woman who’s been working her butt off to throw off my sedentary ways & become fit & healthy. But his approach has some lessons for me. Maybe it does for other insuiln resistant people, too.
On insulin, by another writer at Berardi’s site:
The waters get muddy when we introduce insulin. Insulin is an anabolic hormone, but it’s one that, if chronically elevated, can lead to diabetes, obesity, and heart disease. Therefore, not surprisingly, with insulin we need to perfect the balancing act; just enough to be anabolic but not enough to cause disease. Therefore insulin concentrations should be relatively low. Now, to clarify, I use the term relative when discussing hormones because it is beyond the scope of this essay to get into the details of what these levels should be for individuals of every age or gender. I am speaking in general terms, when I say that for the most part, the levels in healthy individuals should show this pattern.
Human Growth Hormone – relatively high
Testosterone – relatively high
Cortisol – relatively low
Insulin – relatively low
[Note: for women, testoserone levels will be lots lower. Part of the reason women can’t build the kind of muscle mass that Arnold Schwarzenegger or Lou Ferrigno can.]
Insulin in & of itself is not the problem: insulin resistance is. Berardi didn’t say different, I didn’t say different. Ever. What is new to me in Berardi’s approach is that he claims that by proper nutritional timing — which macronutrients (protein, carbs, fats) that you eat when, — you can minimize insulin’s storage of fat (one part of its role as an anabolic hormone) while taking advantage of its anabolic properties re: muscle — i.e., when amino acids are in the blood after eating protein, which is another event inducing insulin secretion. This is why I brought this up: not because I think that “too much insulin” is somehow suddenly magically good for us insulin resistant people, but because this approach, based on a more complete picture of what insulin actually does in the body, leads to some dietary strategies that minimize or reduce fat storage while at the same time maintaining or even (with exercise) increasing lean muscle mass: one avenue towards improving insulin sensitivity.
Note also that when this person challenged my initial post last week about insulin’s role in muscle anabolism, I quoted from four scientific studies — studies published in medical & scientific journals, most of which are peer-reviewed by other scientists before publication, to be sure they aren’t full of nonsense — & the scientists who authored those articles also, every single one of them, said that insulin is anabolic (for muscle as well as body fat). I could have quoted from many more. If anyone wants to look them up for themselves, go to PubMed & search on the terms “protein insulin amino muscle.”
I’m done debating whether insulin is anabolic. Just as I wouldn’t waste my breath debating someone on the question of whether water is wet.