L-Carnitine- Family of Products Nutritional Support for Brain, Heart & Skeletal Muscle Health

Adobe L-Carnitine PDF file Click to return from L-Carnitine Click to return from L-Carnitine To view all JARROW Products go here:

• Antioxidant Protection for the Brain

• Important Co-factor for Energy Production from Fatty Acids

• Helps Regulate Heart Rhythm

• Lowers Triglycerides

• Maximizes Exercise Endurance

• Reduces Post Workout Recovery Time

Nutritional Support for Brain, Heart & Skeletal Muscle Health

L-Carnitine is sometimes referred to as vitamin Bt because of its vitamin-like roles. The body needs lysine, methionine, vitamin C, iron, niacin, and vitamin B-6 to produce limited quantities of L-carnitine, mainly in the liver and the kidneys. L-carnitine is found in small amounts in the diet, primarily in red meat. Mutton and lamb are the richest sources, whereas chicken and turkey contain much less; dairy products contain only small amounts of L-carnitine. The typical daily diet of a non-vegetarian supplies approximately 50 mg of L-carnitine. However, some researchers argue that human beings consumed 500 mg or more of this nutrient throughout most of pre-history. Stone Age humans ate a diet that was very high in hunted meat.

In the human body, L-carnitine is concentrated in the heart and the skeletal muscles, and also in the brain and in the sperm. Research into L-carnitine supplements has found that different forms of L-carnitine may be better suited for enhancing brain and nervous tissues, on the one hand, and muscle tissues, on the other hand. For instance, forms with attached acetyl- groups cross the blood-brain barrier and therefore fall into the first category, whereas forms with attached Krebs Cycle intermediates fall into the second category. Jarrow FORMULAS® supplies a full line of Lcarnitine products to match all needs.

Carnitine -- Essential for Energy

Although L-carnitine is usually referred to as an amino acid, this is technically incorrect since there is no amino (NH2) group present in the molecule. The primary role of L-carnitine in the body is as a biocatalyst or coenzyme. One of its most important functions is in the oxidation of long chain fatty acids, a process that takes place inside the mitochondria, the “energy factories” of the cells. This process is known as beta-oxidation (the rate at which fats are oxidized/burned to supply energy).

L-carnitine converts into an enzyme, acetyl-carnitine transferase, that shuttles fatty acids into the mitochondria and removes waste afterwards. Fats are the preferred source of fuel for the skeletal muscles, and even more so for the heart muscle. As much as 70% of the energy generated in muscle tissues comes from the oxidation of fats!

L-carnitine also increases the rate of oxidation of fats in the liver. This suggests that L-carnitine plays a role in improving energy generation, as well. Some authors argue that in the proper amounts, L-carnitine supplementation during dieting helps to reduce the negative effects of ketosis (the accumulation of waste products of fat metabolism) in those who are susceptible to this problem. Similarly, there is evidence that some forms of obesity may be related to a genetic propensity to produce less L-carnitine. Liver and kidney problems will reduce the body’s production since some four fifths of our total L-carnitine is produced internally by these organs.

L-Carnitine for Sports and Protection

L-carnitine has a definite place in the supplements taken by the amateur and weekend athlete. Research shows that individuals who supplement with L-carnitine while engaging in an exercise regimen are less likely to experience muscle soreness. Moreover, L-carnitine has been given to people with chronic sub-optimal lung function in trials investigating how the body responds to exercise. In these double blind reports, 2 grams of L-carnitine taken twice per day for two to four weeks led to positive changes in breathing response during exercise.

However, the belief that L-carnitine’s effect on energy release will help to build muscle or to improve athletic performance requires qualification. The experiences of healthy athletes with supplementation have been mixed. Of course, the results with well-trained athletes likely are not appropriate for comparisons with those of individuals suffering from excess weight or related difficulties. Current findings indicate that the mixed results came about because many researchers did not know what to look for or did not employ the appropriate dosage levels. As indicated above, L-carnitine supplementation in an experimental study reduced at least some of the aftereffects of strenuous exercise.

One way in which L-carnitine may aid the athlete is by acting locally in the muscle tissues as an antioxidant. Lcarnitine penetrates into the mitochondria themselves, where most of the free radicals of our tissues are generated through the oxidation of food for energy. There is some evidence that L-carnitine serves to spare antioxidants, such as vitamin C, although the mechanism by which this is done has not yet been uncovered. This protection would be in addition to the antioxidant protection given to neurons by protecting against the superoxide radical.

The Krebs Cycle Carnitines:

L-Carnitine Fumarate and GPLC The Krebs Cycle is a major component in the body’s energy pathways. Various intermediate products of the Krebs Cycle have their own special roles in physiology, but also can be used as additional materials for energy production. The heart, in particular, may benefit. The effects upon the heart include improvements in energy production and other parameters. Supplemental Lcarnitine was associated with significantly higher concentrations of pyruvate, ATP and creatine phosphate (crucial components in energy production) in portions of the heart muscle during conditions of extreme stress. (Refer to graph.) Similarly, in tests upon peripheral circulation, L-carnitine was found to be quite useful for improving blood flow.

L-Carnitine Fumarate is L-carnitine that has been stabilized by the addition of fumaric acid to the molecule. L-Carnitine Fumarate is a stable and bio-available carnitine salt supplying 58% carnitine and 42% fumarate. Fumarate is an intermediate in energy production in the Krebs Cycle. It also helps to maintain the production of other intermediates via a process known as anaplerosis. (filling up or replenishing krebs cycle intermediates) As such, it is an active complement to carnitine. The diagram on the next page shows the place of fumarate in the Krebs Cycle.

L-Carnitine Fumarate is designed to:

• Provide Greater Stability

• Yield Superior Uptake Into The Blood Serum

• Provide More Even And Sustained Bio-availability

• Supply Fumarate To The Krebs Cycle

The champion in the area of Krebs Cycle carnitines, however, is GPLC. GPLC is glycine propionyl-L-carnitine. This is a new and patented L-carnitine introduced by Jarrow FORMULAS® in conjunction with Sigma-tau Health Science. GPLC is the first and only Heart-Specific Carnitine™. The focus of this form of L-carnitine is on the muscles, such as the heart, and the vascular system. Compared with at least one other form of L-carnitine, propionyl-L-carnitine appears to produce greater increases in cellular L-carnitine concentrations. Researchers believe that it is transported more easily into muscle fibers and may better support muscle-cell energy production, perhaps because it increases the flow of pyruvate into the Krebs Cycle. Propyionyl-Lcarnitine also exhibits significant free radical scavenging activity and helps to reduce blood from coagulating too readily. Athletes in particular may be pleased with the benefits of GPLC. In addition to the benefits from propionyl-Lcarnitine, GPLC includes the amino acid glycine. Glycine may improve the uptake of carnitine from the intestine and also support Phase 2 detoxification in the liver. This form of L-carnitine is designed to:

• Improve Fat Burning

• Improve Carbohydrate Burning

• Reduce Lactic Acid Build-up In Muscles

• Increase Muscle Glycogen Stores

• Maximize Exercise Endurance

• Reduce Post-workout Recovery Time

• Yield Superior Assimilation And Bioavailability

The propionyl-L-carnitine component of GPLC increases the oxidation of both glucose and lactate (Circulation Research 1995;77:726-734), increases exercise capacity (Am J Med 2001 Jun 1;110(8):616-22), increases both mental and overall energy (Psychosomatic Medicine 2004;66:276–282), and improves muscle glycogen stores while increasing time to muscular fatigue (Muscle Nerve 1997 Sep;20(9):1115-20; J Appl Physiol 1993 Oct;75(4):1595-600). Of course, like other forms of L-carnitine, propionyl-L-carnitine improves the function of the mitochondria and in those who are overweight it should produce a significant increase in the rate at which fats are oxidized to supply energy (Metabolism 2004 Aug;53(8):1002-6). Studies typically have utilized 2 to 3 grams per day for two to six months. Significant muscle loading requires one to two months of daily supplementation.

Brain Health, Acetyl-L-Carnitine and Acetyl-L-Carnitine Arginate

Many authorities point out that acetyl-L-carnitine more readily crosses the blood-brain barrier than do other forms of L-carnitine. Moreover, in the human brain, the acetylation of L-carnitine is a normal event. This is one explanation sometimes given for the greater activity found with acetyl-Lcarnitine than with other forms of L-carnitine in conditions involving the brain.

Acetyl-L-carnitine influences neuronal levels of acetylcholine, a major neurotransmitter responsible for memory and proper brain function, by supporting its synthesis and functions. Acetyll- carnitine also enhances the release of dopamine from neurons and helps it bind to dopamine receptors. As the brain ages, the ability to synthesize and utilize acetylcholine and dopamine declines. Researchers have discovered that acetyl-L-carnitine further acts as an antioxidant within the brain, that it stabilizes cell membranes, and enhances energy production within brain cells.

Acetyl-l-carnitine arginate is another patented form of L-carnitine sold by Jarrow FORMULAS®. In addition to the benefits found with acetyl-L-carnitne, the new form strongly stimulates the growth of neurites in the brain. An in vitro (test tube) study has shown that acetyl-l-carnitine arginate offers a four-fold superiority to acetyl-L-carnitine in stimulating the growth of new neurites, making this a promising new product.

CarnitALL™

CarnitALL™ is a full spectrum carnitine combination comprised of L-carnitine fumarate, GPLC, acetyl-L-carnitine arginate (ALCA) and acetyl-L-carnitine taurinate. It is designed to provide the benefits of carnitine to the various tissues. As noted above, GPLC is a heart-specific carnitine that enhances endothelial function and promotes maximum muscular energetics, whereas ALCA promotes neuronal health. Acetyl-L-carnitine taurinate is a novel molecular combination of acetyl-Lcarnitine with taurine, an amino acid known for stabilizing cell membranes and supporting antioxidant functions.

Truth in Labeling

Jarrow FORMULAS® supplies several different forms of L-carnitine. L-carnitine is provided as a liquid and as Lcarnitine fumarate, a highly stable form. Acetyl-L-carnitine and acetyl-L-carnitine arginate are other stable dry forms that are more active, especially for the brain. The ultimate Krebs Cycle carnitine is GPLC. CarnitAll supplies four forms of carnitine in one. Labeling of L-carnitine products is often misleading. Only part of a stabilized L-carnitine product is actually L-carnitine. For example, it takes 431 mg L-carnitine fumarate to supply 250 mg pure L-carnitine, or 862 mg L-carnitine fumarate to supply 500 mg.

Usage

Take on an empty stomach according to product instructions or as directed by your qualified health consultant.

References

Brass EP, Scarrow AM, Ruff LJ, Masterson KA, Van Lunteren E. Carnitine
delays rat skeletal muscle fatigue in vitro. J Appl Physiol. 1993 Oct;75(4):
1595-600.
Brevetti G, Fanin M, De Amicis V, Carrozzo R, Di Lello F, Martone VD,
Angelini C. Changes in skeletal muscle histology and metabolism in patients
undergoing exercise deconditioning: effect of propionyl-L-carnitine. Muscle
Nerve. 1997 Sep;20(9):1115-20.
Carta A et al. Acetyl-L-carnitine and Alzheimer’s disease: Pharmacological
considerations beyond the cholinergic sphere. Ann N Y Acad Sci 1993;695:
324-326.
Costell M, O’Connor JE, Grisolia S. Age-dependent decrease of carnitine
content in muscle of mice and humans. Biochem BioPhys Res Commun
1989;161(3):1135-1143.
Fiori L, Rampello L. L-acetylcarnitine attenuates the age-dependent
decrease of NMDA-sensitive glutamate receptors in rat hippocampus. Acta
Neurol (Napoli) 1989;11(5):346-350.
Hiatt WR, Regensteiner JG, Creager MA, Hirsch AT, Cooke JP, Olin JW,
Gorbunov GN, Isner J, Lukjanov YV, Tsitsiashvili MS, Zabelskaya TF, Amato
A. Propionyl-L-carnitine improves exercise performance and functional
status in patients with claudication. Am J Med. 2001 Jun 1;110(8):616-22.
Huertas R et al. Respiratory chain enzymes in muscle of endurance athletes:
Effect of L-carnitine. Biochem BioPhys Res Commun 1992;188:102-106.
Marconi C. Effects of L-carnitine loading on the aerobic and anaerobic
performance of endurance athletes. Eur J Appl Physiol 1985;54(2):131-135.
Ruggiero FM et al. Effect of aging and acetyl-L-carnitine on the lipid
composition of rat plasma and erythrocytes. Biochem BioPhys Res
Commun 1990;170(2):621-626.
Schonekess BO, Allard MF, Lopaschuk GD. Propionyl L-carnitine
improvement of hypertrophied heart function is accompanied by an increase
in carbohydrate oxidation. Circ Res. 1995 Oct;77(4):726-34.
Swart I et al. The effect of L-carnitine supplementation on plasmea carnitine
levels and various performance parameters of male marathon athletes.
Nutrition Research 1997;17:405-414.
Taglialatela G, Navarra D, Olivi A, et al, Neurite outgrowth in PC12 cells
stimulated by acetyl-L-carnitine arginine amide. Neurochem Res 1995
Jan;20(1):1-9.
Vermeulen RCW, Scholte HR. Exploratory Open Label, Randomized
Study of Acetyl- and Propionylcarnitine in Chronic Fatigue Syndrome.
Psychosomatic Medicine. 2004;66:276–282.
Wutzke KD, Lorenz H. The effect of l-carnitine on fat oxidation, protein
turnover, and body composition in slightly overweight subjects. Metabolism.
2004 Aug;53(8):1002-6.
Zhi-Quan He et al. Body weight reduction in adolescents by a combination of
measures including using L-carnitine. Acta Nutrimenta Sinica 1997;19(2):146

Source: Jarrow Formulas