1. Introduction

Nutrition is one of the most important topics of medical sciences and experts believe that observing nutrition principles may have a key role in health promotion and disease prevention in all periods of life ^[1]. Most athletes are familiar with dietary supplements which are used for improving athletic performance ^[2]; such as LCLT (3-hydroxy-4-N-trimethylammonio butanoate) with a molecular weight of 161 g/mol which was extracted from meat for the first time and is involved in the transport of fatty acids into mitochondria ^[3]. LCLT deficiency leads to impaired fats metabolism ^[4]. On the other hand, physical activity results in reduced LCLT in muscles ^[5]. Despite abundant reserves of triglycerides in the body, liver and muscle glycogen stores are limited, thus their depletion is expectable during exercise especially during prolonged endurance activities ^{[6, 7]}. Several studies have been performed about the effects of LCLT on fatty acids consumption. In this context, some have indicated that supplementation with LCLT increases fat oxidation ^[8], decreases carbohydrate oxidation ^[9], improves exercise ^[10], and reduces the recovery time ^[11]; while, some studies have reported no effect on carbohydrate oxidation ^[12], no change in maximal oxygen consumption (VO_2max) ^[13], and no change in heart rate, oxygen consumption, and blood lactate concentration ^[14].

Research evidences show that the findings about acute effects of LCLT supplement on metabolic factors and athletic performance in athlete and non-athlete population are often disparate and inconsistent, such that some reports show the beneficial impacts of this supplementation on endurance performance and others not. Therefore, the aim of the present study was to evaluate the effects of acute consumption of 3 g LCLT on lipid metabolism in elite wrestlers performing exhaustive aerobic exercise, in order to provide new results along with other research findings.

2. Materials and Methods

The statistical population of this single-blind clinical trial consisted of elite wrestlers of Ahvaz. Following determination of sample size, 20 male wrestlers with full consent were selected as samples and signed the consent form. To measure their anthropometric variables, they were examined a few days before the test and the data on height, weight, and body mass index were determined. They were then specifically divided into two equal groups of supplement and placebo. The supplement group received 3 g of LCLT dissolved in 200 ml water plus 6 drops of lemon juice and the placebo group received 200 ml water plus 6 drops of lemon juice. The sample size was determined based on the findings of some studies on the effects of LCLT and sample size estimation for comparing the two groups, with a type I error at 5%. The confidence level for estimating sample size in this study was 95%. The subjects (Ahvaz elite wrestlers) hold national, Asian, and world championships, and they do not have any metabolic disease such as diabetes, asthma, or cardiovascular disease. Both experimental and control groups were prohibited to exercise 48 hours before the test. They were also asked to avoid consumption of coffee and dairy products at least a day before the test, to put themselves in normal conditions for the test, and to be fasting 12 to 14 hours before the test. LCLT tartrate (68.2% LCLT, 31.8% L-tartrate) was obtained as gift from the Shahr Darou Company.

Test performance: The supplement and placebo were consumed by the subjects 90 minutes before the exercise. Five milliliter blood sample was obtained from them at the test morning, after 15 min rest. To obtain serum, blood samples were centrifuged for 10 min at 2000 RPM. Serum high-density lipoprotein (HDL), low density lipoprotein (LDL), and very low-density lipoprotein (VLDL) were measured using standard kits (Bionic, Iran) with a sensitivity of 1 mg/dL (first stage). The exercise protocol; Conconi test (15), was performed 90 min after receiving the supplement and placebo as follows; after a warm-up, the participants start to run on a treadmill (Hp/cusmos-Germany) with an initial speed of 8 km/h which raised 0.5 km/h every 200 m and continued until the subject exhausted. Immediately after the test, the traveled distance was recorded and the second blood was sampled (second stage). The third blood sample was taken 30 min after the exercise (third stage) as mentioned earlier. Biochemical and physiological variables were compared in SPSS-16 using ANOVA inferential analysis (MANOVA). To evaluate normal distribution of original variables and to study homogeneity of variance, the parametric Kolmogorov-Smirnov test and the Leaven test were used, respectively. The significance level of mean difference was considered p < 0.05.

3. Results

A- The initial investigation showed that LCLT consumption had no side effects on the subjects, such as stomach ache or diarrhea which often occur following the consumption of some supplements. The participants were able to successfully complete the test protocol. Table 1 depicts the anthropometric characteristics of the two study groups in this exercise trial. As the results show, both groups were homogeneous in terms of anthropometric parameters and there are no significant differences in any of the characteristics.

Table 1. Anthropometric characteristics of subjects (mean ± SD)

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B- Effect of LCLT on serum HDL

As in Figure 1, HDL levels shows no significant difference before and after exhaustive exercise in the experimental and control groups, while serum HDL was higher in the experimental group than the control group after resting (p < 0.035).

Figure 1. Effect of LCLT on serum HDL, 90 min before and immediately after exhaustive activity and 30 min after resting in control and experimental groups (10 persons per group). * Significant difference at p < 0.05

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Figure 2. Effect of LCLT on serum LDL, 90 min before and immediately after exhaustive activity and 30 min after resting in control and experimental groups (10 persons per group). * Significant difference at p < 0.05

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C- Effect of LCLT on serum LDL

As Figure 2 illustrates, the levels of LDL before and after exhaustive exercise have no significant difference in the experimental and control groups, while serum LDL is lower in the experimental group than the control group after resting (p < 0.018).

D- Effect of LCLT on serum VLDL

As in Figure 3, the level of VLDL before and after exhaustive exercise and resting has no significant difference in the experimental and control groups.

Figure 3. Effect of LCLT on serum VLDL, 90 min before and immediately after exhaustive activity and 30 min after resting in control and experimental groups (10 persons per group)

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4. Discussion

To gain a competitive advantage and to achieve a higher level of health or physical performance, athletes experience various diet or artificial methods containing nutritional supplements or injectable medications ^[16]. Dietary supplements which improve athletic performance are familiar to most athletes ^[11]. The primary role of LCLT is focused on lipid metabolism however, scientific evidence confirms its role in carbohydrate metabolism as well and in fact, there is a strong correlation between muscle carnitine and Krebs cycle. Fat oxidation is triggered in rabbits following L-carnitine consumption ^[17]. Muscle carnitine concentration is directly proportional to muscle glycogen stores ^[18]. Studies show that L-carnitine improves fat metabolism and preserves glycogen ^[19]. Another study shows that L-carnitine increases fat oxidation and hence CO₂ elimination ^[20]. Other studies show ineffectiveness of L-carnitine on blood lipid levels ^[21]. What distinguishes the present research with these studies is the readiness of the subjects and the exercise type. Regarding the role of L-carnitine in transferring free fatty acids into mitochondria, particularly during sports, it is expected that its supplementation and thus its increase in plasma be associated with increased entry of free fatty acids into the cell’s mitochondria; the main outcome of which is the preservation of liver and muscle glycogen to continue carbohydrate oxidation, particularly in the later stages of exercise and hence delayed exhaustion. These benefits have been confirmed by many scientific evidences.

5. Conclusion

Single-dose consumption of 3 g LCLT, 90 min before starting exercise can improve the performance through transporting of blood free fatty acids into mitochondria. The results of the present study showed that acute supplementation with LCLT tartrate increased HDL and decreased LDL, while not affected VLDL following an exhaustive aerobic activity. To improve fatty acid metabolism and their records, athletes of aerobic sports like wrestling (e.g. taekwondo and gymnastics) can be recommended to consume 3 g LCLT, 90 minutes before exercise. To analyze more confidently the results, it is suggests to measure glycogen concentration and LCLT in blood and muscle in future studies.

Acknowledgement

The authors of the paper would like to sincerely thank the Shahr Darou Company for providing L-carnitine.

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