12/02/2012
From the article: Jitomir and Willoughby. Leucine for retention of lean mass on a hypocaloric diet. Journal of Medicinal Food (2008) vol. 4 (11) pp. 606-609 is the paragraph below describing what I called the "energy on demand" model in the New Evolution Diet that I relied upon for my type-1 diabetic, wife and son. I had worked it out many years ago using economics and just enough knowledge of metabolism. As I say in the book, we handed the job of supplying glucose to the liver with a diet high in amino acids rather than rely, as most people seem to do, on ingesting carbohydrate. It was this point that was often in contention in my discussions with doctors who recommended the high-carb ADA diet.
"Another important link between AA (amino acid) metabolism and glucose homeostasis is the role of the leucine in the formation of glutamine and, consequently, the glucose-alanine pathway. BCAAs participate in transamination reactions with the transfer of their nitrogen group to glutamate, which generates glutamine. Subsequently, the nitrogen group may be transferred to pyruvate, which generates alanine. In the liver, alanine will be deaminated and used as a substrate for gluconeogenesis (my bolding). Therefore, sufficient dietary BCAAs allow pyruvate to be used as a gluconeogenic substrate, which enhances the ability of the liver to secrete glucose to regulate blood sugar as required. As detailed by Layman, the large influx of glucose on a high-carbohydrate diet requires that blood glucose control be mediated by insulin-stimulated cellular uptake of glucose, which is a less precise process than the slow secretion of gluconeogenic products."
"Less precise" doesn't begin to tell the story, which many type-1 diabetics know as chasing carbs with insulin and then chasing insulin with carbs. It is an exhausting and even dangerous cycle. Insulin is a storage hormone with imprecise ability to manage the flow of glucose the brain requires. The liver releases glucose "on demand" and is far more precise and smoother as well.
A few more choice paragraphs from this paper that emphasizes the importance of leucine, what I call the master BCAA in glucose control and muscle protein synthesis.
GLUCOSE HOMEOSTASIS Though the impact of protein on glucose homeostasis is controversial, the accumulated literature supports that a diet high in protein and reduced in carbohydrate limits post-prandial insulin response and allows for better blood glucose regulation in diabetics. As reviewed by Layman, the ability of protein to maintain glucose homeostasis is a result of the liver's use of protein carbon skeletons as the primary gluconeogenic substrates; hence, a high-protein diet can allow for blood glucose to be maintained by the liver via gluconeogenesis. In fact, gluconeogenic products account for 70% of fasting liver glucose release, and many AAs are the primary gluconeogenic substrates.
Leucine supplementation during a period of hypocalorism may serve to promote gluconeogenesis for the maintenance of blood glucose when dietary glucose is limited and protein is plentiful. Hence, the benefits of leucine supplementation may be optimized when given in conjunction with a high-protein diet, instead in combination with a diet based on the current protein RDA of 0.8 g/kg/day. Furthermore, high-protein weight loss diets may be designed to include dietary sources inherently high in leucine, such as dairy. High-leucine foods may contain up to 25% of AAs as BCAAs and 15% of AAs as leucine. Furthermore, since leucine, valine, and isoleucine are the only AAs not metabolized in the liver, their concentrations in the diet have a direct impact on cellular concentrations. The ability of leucine to participate in signaling and oxidative substrate roles is dependent on having a sufficient intracellular concentration remaining after structural roles are satisfied. Hence, a diet must be sufficiently high in leucine to gain the signaling and metabolic benefits; the traditional "nitrogen balance" method of determining protein needs does not account for the varied roles of AAs in the body. (I think this ultimately means that current RDA of protein is less than it should be, because of failure to appreciate its role in gluconeogenesis and as an energy substrate.
It turns out that BCAAs stimulate mitochondrial biogenesis, a point I have mentioned but will take up in more detail later. Notice also the importance of hypocalorism (intermittent fasting) as a way of promoting gluconeogenesis and mitochondrial biogenesis. It is for these reasons, and others, that Dr. D and I developed the Guardian BCAAs with B12. You will not feel hungry or suffer brain panic from lack of glucose if you take our BCAA
