On an earlier thread Dick wrote:
"The Awesome Foursome is worth noting, including as it does Mg (a member of the Terrific Trio of K, Mg, and taurine) and COQ10, which are so often mentioned here. I haven't seen as much here on carnitine so it might be worthwhile to discuss such things as dosages for various conditions and the differences between l-carnitine and acetyl-l-carnitine."
Hi again Dick -
To get a dialogue going, here are some excerpts from Chapter 5, 'L-Carnitine: The Energy Shuttle' in the book 'The Sinatra Solution - Metabolic Cardiology'. The chapter covers a lot of ground - 40 pages of text! - but the bottom line is that carnitine is absolutely essential for energy (ATP) synthesis, hence cardiac function, for life itself, and that many of us, if not most, are deficient, and that the supplement form doesn't seem to matter much, if at all. Chapter 8 has recommended L-carnitine supplement dosages for various conditions ranging from 350 to 3,000 mg per day. For afib it's 1,000 to 2,000 mg per day.
Erling
"Since Coenzyme Q10 and carnitine synthesis may diminish with age, relative deficiencies may develop over time. This is one reason why it may be important to get carnitine both in the diet and in supplement form."
"Carnitine is actually derived from two amino acids, lysine and methionine.... complemented with niacin, vitamin B6, vitamin C, and iron."
"Remember, the word carnitine comes from 'carnis', meaning flesh or meat. The greatest amounts are found in mutton from older sheep, followed by lamb, beef, other red meat, and pork. Although carnitine is found in many foods, the quantities in plants are exceedingly small. So, vegetarians are, in this regard, "behind the eight ball". Not only do pure vegetarians fail to get enough carnitine in their diets, they may also lack the methionine and lysine needed to synthesize it in their bodies."
"The principal function of carnitine is to facilitate the transfer of long-chain fatty acids across the inner mitochondrial membrane to begin the process of 'beta-oxidation' we learned about in Chapter 3 [ATP: The Miracle of Life]. In fact, carnitine is the only carrier that can do this, and its abundant presence in the cell is an absolute requirement for life." [Go to 'Mitochondrial DNA in Aging and Disease' for graphics showing mitochondrial structure, also how / where ATP is recycled from ADP in the 'respiratory chain', aka 'electron transport chain', within the inner membrane: [
www.nslc.wustl.edu]]
"Without L-carnitine, fatty acids can't penetrate the inner mitochondrial barrier [membrane]. Therefor, the rates of beta-oxidation, oxidative phosphorylation and energy recycling [ADP -> ATP] are all dependent upon the amount of carnitinr in the tissue."
"... a certain form of carnitine, propionyl-L-carnitine (PLC), has been shown to be a powerful vasodilator. In this capacity carnitine helps to open blood vessels, increasing the blood supply to the heart ... So, the physiological roles of carnitine are quite diverse and offer many ways to enhance a multitude of metabolic functions of the body ... PLC is a carnitine derivative that, along with L-carnitine (base) and acetyl-L-carnitine, forms a component of the body's carnitine pool... "Much of the work has been focused on the eventual release of a prescription form of PLC. A dietary version of PLC, Glycine-Propionyl-L-Carnitine (GPLC) has been released three years ago [2003?] .... "Studies ... have shown GPLC to be well tolerated on actual doses of three grams (3,000 mg) daily". "Maximal blood levels of PLC are reached in approximately 3 1/2 hours, while with most L-carnitine forms approximarely 15 hours are required. But for GPLC, serum uptake results in 1 1/2 hours...."
"Because carnitine doesn't get fully absorbed when taken orally, ingesting it three times per day is the preferred method.... the oral bioavailability leaves much ti be desired" "Bioavailability refers to the amount of nutrient that actually gets delivered to the tissues, and surprisingly, it actually decreases as the dose increases."
"A third study, also in a rat model, is even more interesting .... After heart attacks were induced the hearts were treated with... L-carnitine, acetyl-L-carnirine, or propionyl-L-carnitine. All three carnitine derivatives were used to see if there were differences in their metabolic effect on the heart... All three of the carnitines markedly improved recovery of energy compounds in the tissue.... L-carnitine quickly increased energy levels... Acetyl-L-carnitine was even stronger in its early response bur did not keep the energy level as high as L-carnitine over the entire study period.... In the propionyl-L-carnitine group the very early recovery was not as strong as either the L-carnitine group or the acetyl -L-carnitine group, but by the end of the study the recovery was greater.... The study showed that treatment with any of the carnitines tested improves the energetic state of the heart ....."