The Truth About L-Carnitine

Nestle has recently introduced a new product called Nestea Fit to directly compete with Del Monte’s Fit ‘N Right. Both products have successfully positioned itself in the market as a healthy drink boosting with L-Carnitine that according to them is aids in burning of stored fats into fuels.
In my quest to lose weight (a lot of weight), I have been drinking both of these products for quite some time now. And as you might have guessed it, so far I haven’t lost a pound of my weight. =( So I started asking, what really is L-Carnitine? And can it really help burn fat? I did some research and hopefully you’ll be enlightened after reading this blog.

According to Chasefreedom.com, L-Carnitine is a nitrogen-containing, short-chain carboxylic acid. It is water-soluble, vitamin-like compound that is readily synthesized in the body from lysine and methionine. It can be easily obtained in a number of foods like meat, particularly beef, sheep and lamb, milk, cheese and poultry as well as in some fruits and vegetables. Our body can even make small amounts of L-Carnitine with the help of lysine and methionine and vitamins such as niacin, b6 and vitamin C (nahanniriverherbs.com).

The primary function of carnitine in the body is to regulate fat oxidation (fat burning). L-Carnitine is responsible for transporting fat to the fat furnace in our cells called mitochondria. Unless fat makes it to the mitochondria, it cannot be oxidized, no matter how much you exercise or diet. (nahanniriverherbs.com)

How does L-Carnitine Work?

Carnitine boosts energy by stimulating the body's burning of tryglycerides as fuel, and sparing the supply of glycogen stored in the liver for heavier exertion. During exercise, the body will burn fat at a rate of 75-80% of maximum exertion, thus less glycogen from carbohydrates is burned. L-carnitine allows the body to burn more fat, save more glycogen, and ultimately boost stamina and endurance. By providing more fat to the muscles, carnitine makes accessible an otherwise unavailable energy source. (vanderbilt.edu)

Is this the recipe for success? According to proponents of L-Carnitine, it is the essential amino acid in the optimum fat burning process. They believe that carnitine is to the human body, what a turbo mechanism is to a car: both provide optimal fuel and performance. Minus L-carnitine, fatty acids would have a difficult time permeating the walls of the mitochondria. Energy, stored in carbohydrates and fats, is required to work the muscle. Carbohydrates are converted from glucose to glycogen, to be stored in liver and muscle cells. Eventually, the body turns to fat storage for energy, and possibly, with more ease in the presence of L-carnitine. This is where L-carnitine as a supplement enters. During high energy output, the supply of L-carnitine becomes exhausted. Is it possible to compensate for this decrease solely through metabolic processes and diet? Or is an additional carnitine supplement needed for the extra boost? Judging from the variety of carnitine products now on the market, apparently many believe an additional outside source proves beneficial. (vanderbilt.edu)

Is It Effective?

Recent research done on L-carnitine shows mixed results concerning its effectiveness. A number of journal studies involving the administration of l-carnitine to both human participants and animal subjects reveal both adverse and positive results. In Training and Nutrition, J. P. Krabbe (1996) reports that although L-carnitine is important in the correction of human carnitine deficiency, once such a deficiency is corrected, more is unnecessary. Since humans get plenty of it from meat and dairy products, most healthy individuals exceed the recommended daily dosage. Krabbe writes, "Also true is that once any deficiency is corrected, that the majority will get excreted. Thus, more is not better, unless you need it." (http;//ww.cyberiron.com/supplement/carnitine.html)

Such a case is reported in the Journal of Clinical Neurology. A woman showed secondary carnitine deficiency as a result of anorexia nervosa and liver damage, which rendered her liver incapable of synthesizing l-carnitine (Negoro, Tsuda, Kato & Morimatsu, 1995). Her deficiency was treated with oral administration of L-carnitine.

M. H. Williams (1992) researched the use of ergogenic aids among endurance athletes, and found L-carnitine to be ineffective. Factors that did in fact enhance performance were genetic endowment, proper training and nutrition, and an adequate supply of fluids and carbohydrates. Conversely, McCarty (1995) found that carnitine may promote weight loss in exercise regimens by enhancing glucose homeostasis in the liver. At the Nestle Research Centre, researchers studied the effect of L-carnitine on exercise metabolism after depletion of muscle glycogen. Nine healthy male subjects received L-carnitine or a placebo and then were submitted to 60 minutes of exercise after an overnight fast. It was concluded that metabolism was not influenced by carnitine supplementation (Decombaz, Deriaz, Acheson, Gmuender & Jequier, 1993). A similar study found that during submaximal exercise, carnitine supplementation did not result in increased lipid oxidation or muscle carnitine content, indicating that the administered carnitine was not absorbed by the body (Vukovich, Costill & Fink, 1994).

Conclusion?

According to Hilary Spruytenburg, author L-Carnitine: Powerful Endurance Enhancer, or Unnecessary Ergogenic? published in Vanderbilt.edu, L-Carnitine is just an unnecessary ergogenic aid where only individuals with L-Carnitine deficiency will benefit. It is only effective as the consumer’s belief in the product.

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Disappointing, huh? Well, we can still lose weight the old fashion way. That is, a balance diet and a regular exercise.