Summer 2001 Issue — Reaping the benefits of L-Carnitine
The development of an innovative functional food concept

Paula Gaynor, Ph.D.

Lonza Inc., Fair Lawn NJ. USA

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Introduction

In recent years, there has been much emphasis placed on the use of nutraceuticals to promote various health benefits and/or to play a role in disease "prevention"/ While the use of some of these so-called nutraceuticals has relied on anecdotal reports of efficacy, clinical research on a global basis continues to show the benefits of L-Carnitine, the primordial nutraceutical ingredient. Let's review some of the latest research and look at how L-Carnitine and its stable, non-hygroscopic salts, such as L-Carnitine, L-Tartrate and L-Carnitine Magnesium Citrate, may be incorporated successfully into health-promoting food and drink products.

L-Carnitine, a vitamin-like Nutrient

But firstly, what is L-Carnitine? Quite simply, L-Carnitine is an amino acid-like and vitamin-like nutrient. A small amount of L-Carnitine is naturally produced on a daily basis within the human body and high concentrations of L-Carnitine are present in the human heart and skeletal muscle. L-Carnitine is also present in the foods we eat - it is found to varying extents in foods of animal origin (generally, the best source is red meat) while fruit and vegetables contain very little, if any, L-Carnitine. The function of L-Carnitine in the body is to ensure the production of energy from fat. L-Carnitine shuttles long chain fatty acids into the mitochondria, the "furnace of the cell" for beta-oxidation (fat-burning) and ultimately, cellular energy is generated in the form of ATP.

Wide Range of Applications

Extensive clinical research has discovered that L-Carnitine has a beneficial role to play in a broad array of applications. It is widely accepted that L-Carnitine has significant cardio-protective properties. Studies also indicate that L-Carnitine is useful as part of a weight management program. L-Carnitine is considered to be an essential nutrient for infants because unlike adults, infants are unable to synthesize L-Carnitine in their bodies. L-Carnitine is present in breast milk and for some years now, manufacturers of soy-based infant formula have been fortifying their products with L-Carnitine, which would otherwise be devoid of this conditionally essential nutrient.

L-Carnitine is extremely popular among physically active people who supplement with L-Carnitine to help improve their performance, while simultaneously delaying the onset of fatigue. The latest breakthrough clinical research points to another important role for L-Carnitine: enhancing recovery from strenuous exercise. This latest research provides physically active and even inactive people with an additional reason to supplement with this nutraceutical.

New Research on L-Carnitine and Recovery from Exercise

"Weekend warriors" or recreational athletes typically experience soreness and stiffness in exercised muscles following an extended lay-off from exercise. A temporary soreness may persist for several hours whereas a residual soreness of Delayed Onset Muscle (DOMS) may appear later and last for 3 to 4 days after the unaccustomed exercise. On a temporary basis, DOMS can adversely affect muscular performance, both from voluntary reduction of effort and from inherent loss of muscle capacity. Nearly everyone has experienced DOMS at some time, therefore there is a huge potential for a nutraceutical that can help battle this problem.

The most recent clinical study showed that L-Carnitine L-Tartrate supplementation significantly helps "weekend warriors" during recovery from high intensity exercise. The study was conducted by a team of scientists led by Professor William Kraemer and Dr Jeff Volek at Ball State University in Indiana. Lonza Group, the largest manufacturer of l-Carnitine in the world, funded the study. Due to a patented production process, Lonza Group is the only L-Carnitine manufacturer able to supply 100% pure L-Carnitine without any harmful D-Carnitine in their product line, hence the brand name and sign of quality assurance L-CARNIPURE®. Preliminary details of the study were presented recently at the Experimental Biology meeting in Orlando and at the Vita foods conference in Geneva.

Using a balanced, placebo, cross-over design, ten healthy active men (mean age 23.7 years) volunteered and acted as their own control taking either a placebo or an L-CARNIPURE® L-Carnitine L-Tartrate supplement (equivalent to 2g L-Carnitine/day) for 3 weeks prior to the performance of a controlled exercise session. Various indicators of recovery were measured in the first 3 hours after the exercise and then at 24,48,72 and 96 hours after the exercise session. The exciting results of the study indicated that the supplementing with L-Carnitine L-Tartrate prior to high intensity exercise is significantly effective in assisting recovery. More specifically, supplementation allows for a decreased production of free radicals, less tissue damage, reduced muscle soreness and better utilization of fat as an energy source during recovery.

Another recently published study also looked at the effect of L-Carnitine L-Tartrate supplementations on recover from intense exercise. This study differed from the DOMS study above in that it focused on the effect on supplementation on accerlatering short-term recovery after strenuous exercise. The study was performed under the guidance of Professor Paul Walter at the University of Basel in Switzerland. The Lonza Group also sponsored this study.

In this double blind, placebo-controlled, cross-over study, twelve healthy men and women (mean age 25.7 years, 6 untrained and 6 trained) volunteered and acted as their own control taking either a placebo or an L-CARNIPURE ® L-Carnitine L-Tartrate supplement (equivalent to 2g L-Carnitine/Fay) for 5 days. The power output of each individual was initially established then each subject performed a strenuous 15-minute bike ride. Recover was subsequently measured in terms of power output that could be generated following the bike ride. The mean power output measured during 25 minutes following strenuous exercise was improved significantly by 11-14% following supplementation with L-Carnitine L-Tartrate for 5 days, thereby indicating that L-Carnitine also has a role to play in enhancing short-term recovery.

Dosage Considerations

As mentioned previously, the body makes a small amount of L-Carnitine on a daily basis. In addition, we get L-Carnitine through the foods we consume - approximately 100-300 mg/day for the typical Western, non-vegetarian diet. So why is there need for higher doses? The needs stem from clinical evidence that suggests that around 2g/day is necessary if we are to benefit from the health promoting properties of L-Carnitine. It is also worth bearing in mind that, currently, due to the decreased tendency to consume red meat, people are likely to be getting less than optimal amounts of L-Carnitine in their diets.

Safety Matters

L-Carnitine is a safe and non-toxic substance. An independent panel of experts in the US has granted L-Carnitine self-affirmation GRAS status, meaning that it is Generally Recognized As Safe. It is important to remember that Carnitine can exist as D or L-Carnitine. While L-Carnitine is the form found in nature and is biologically active, D-Carnitine is biologically inactive and because of its potential detrimental effects on health, the FDA has banned the import of D and D, L-Carnitine (a mixture of D and L-Carnitine) into the US since 1983. It is recommended that companies who currently purchase L-Carnitine, or intend to in the future, ensure that there supplier pure L-Carnitine with no detrimental D-Carnitine present.

Using L-Carnitine in Functional Foods

Gone is the era when L-Carnitine could only be found to any significant extent in red meat. Nowadays, throughout the world, L-Carnitine can be found in tablets (including effervescent and chewables), capsules, energy drinks, probiotic drinks, liquid concentrates, energy bars and infant formulas, to mention but a few products.

As functional food ingredients, L-Carnitine and its salts, L-Carnitine L-Tartrate and L-Carnitine Magnesium Citrate can be used in any application where dietary enhancement is appropriate. All these products are bright white, heat stable, highly water-soluble and form colourless solutions. L-Carnitine is inherently hygroscopic (meaning that it absorbs moisture) and therefore is better suited to liquid applications or applications where a low dose of L-Carnitine is required e.g. infant formula. On the other hand, L-Carnitine L-Tartrate and L-Carnitine Magnesium Citrate are both stable, odourless, non-hygroscopic salts of L-Carnitine which are perfect for any solid or liquid application. In addition, L-Carnitine L-Carnitine L-Tartrate has a pleasant citrus taste, which is very appealing in drinks, bars, effervescent tablets, etc.

In summary

L-Carnitine is a vitamin-like nutrient, which is essential in facillating the production of energy from fat in the human body. Extensive research has shown the effectiveness of L-Carnitine in applications such as exercise, weight management and heart health. Furthermore, ongoing clinical research continues to uncover new and very exciting applications of L-Carnitine, for example in helping recovery from exercise. The explosion in the interest in L-Carnitine can be attributed to a number of factors including its basic function in helping convert fat into energy, its efficacy, its excellent safety profile and, of course, its suitability for processing.

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