Effects of nine weeks L-Carnitine supplementation on exercise performance, anaerobic power, and exercise-induced oxidative stress in resistance-trained males

다국어 초록 (Multilingual Abstract)

[Purpose] Studies of L-carnitine in healthy athletic populations have yielded equivocal results. Further scientific-based knowledge is needed to clarify the ability of L-carnitine to improve exercise capacity and expedite the recovery process by reducing oxidative stress. This study aimed to examine the 9-week effects of L-carnitine supplementation on exercise performance, anaerobic capacity, and exercise-induced oxidative stress markers in resistance-trained males.
[Methods] In a double-blind, randomized, and placebo-controlled treatment, 23 men (age, 25±2y; weight, 81.2±8.31 kg; body fat, 17.1±5.9%) ingested either a placebo (2 g/d, n=11) or L-carnitine (2 g/d, n=12) for 9 weeks in conjunction with resistance training. Primary outcome measurements were analyzed at baseline and at weeks 3, 6, and 9. Participants underwent a similar resistance training (4 d/w, upper/lower body split) for a 9-week period. Two-way ANOVA with repeated measures was used for statistical analysis.
[Results] There were significant increases in bench press lifting volume at wk-6 (146 kg, 95% CI 21.1, 272) and wk-9 (245 kg, 95% CI 127, 362) with L-carnitine. A similar trend was observed for leg press. In the L-carnitine group, at wk-9, there were significant increases in mean power (63.4 W, 95% CI 32.0, 94.8) and peak power (239 W, 95% CI 86.6, 392), reduction in post-exercise blood lactate levels (-1.60 mmol/L, 95% CI -2.44, -0.75) and beneficial changes in total antioxidant capacity (0.18 mmol/L, 95% CI 0.07, 0.28).
[Conclusion] L-carnitine supplementation enhances exercise performance while attenuating blood lactate and oxidative stress responses to resistance training.

참고문헌 (Reference)

1 Volek JS, "l-Carnitine l-tartrate supplementation favorably affects markers of recovery from exercise stress" 282 : E474-E482, 2002

2 Sawicka AK, "l-Carnitine Supplementation in Older Women. A Pilot Study on Aging Skeletal Muscle Mass and Function" 10 : E255-, 2018

3 Kraemer WJ, "The effects of L-carnitine L-tartrate supplementation on hormonal responses to resistance exercise and recovery" 17 : 455-462, 2003

4 Cribb PJ, "The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine" 16 : 494-509, 2006

5 Parandak K, "The effect of two-week L-carnitine supplementation on exercise-induced oxidative stress and muscle damage" 5 : 123-128, 2014

6 Ogborn D, "The Role of Fiber Types in Muscle Hypertrophy : Implications for Loading Strategies" 36 : 20-25, 2014

7 Karlic H, "Supplementation of L-carnitine in athletes: does it make sense?" 20 : 709-715, 2004

8 Arican O, "Serum levels of TNF-alpha, IFN-gamma, IL-6, IL-8, IL-12, IL-17, and IL-18 in patients with active psoriasis and correlation with disease severity" 2005 : 273-279, 2005

9 Spriet LL, "Regulation of pyruvate dehydrogenase(PDH)activity in human skeletal muscle during exercise" 30 : 91-95, 2002

10 Hakim J, "Reactive oxygen species and inflammation" 187 : 286-295, 1993

11 Síktar E, "Protective role of L-carnitine supplementation against exhaustive exercise induced oxidative stress in rats" 668 : 407-413, 2011

12 Vider J, "Physical exercise induces activation of NF-kappaB in human peripheral blood lymphocytes" 3 : 1131-1137, 2001

13 Bulucu F, "Oxidative stress status in adults with nephrotic syndrome" 53 : 16973-, 2000

14 Birben E, "Oxidative stress and antioxidant defense" 5 : 9-19, 2012

15 Setia S, "Nuclear factor kappa B : a pro-inflammatory, transcription factor-mediated signalling pathway in lung carcinogenesis and its inhibition by nonsteroidal anti-inflammatory drugs" 31 : 27-37, 2012

16 Schmitz SM, "Nine weeks of supplementation with a multi-nutrient product augments gains in lean mass, strength, and muscular performance in resistance trained men" 7 : 40-, 2010

17 Sahlin K, "Metabolic factors in fatigue" 13 : 99-107, 1992

18 Siliprandi N, "Metabolic changes induced by maximal exercise in human subjects following L-carnitine administration" 1034 : 17-21, 1990

19 Volek JS, "L-Carnitine L-tartrate supplementation favorably affects markers of recovery from exercise stress" 282 : E474-E482, 2002

20 Vecchiet L, "Influence of L-carnitine administration on maximal physical exercise" 61 : 486-490, 1990

21 Conner EM, "Inflammation, free radicals, and antioxidants" 12 : 274-277, 1996

22 Jacobs PL, "Glycine propionyl-L-carnitine produces enhanced anaerobic work capacity with reduced lactate accumulation in resistance trained males" 6 : 9-, 2009

23 Bloomer RJ, "Glycine propionyl-L-carnitine modulates lipid peroxidation and nitric oxide in human subjects" 79 : 131-141, 2009

24 Evans M, "Efficacy of a novel formulation of L-Carnitine, creatine, and leucine on lean body mass and functional muscle strength in healthy older adults : a randomized, double-blind placebo-controlled study" 14 : 7-, 2017

25 García-López D, "Effects of eccentric exercise on NF-kappaB activation in blood mononuclear cells" 39 : 653-664, 2007

26 Kurutas EB, "Effects of antioxidant therapy on leukocyte myeloperoxidase and Cu/Zn-superoxide dismutase and plasma malondialdehyde levels in experimental colitis" 2005 : 390-394, 2005

27 Atalay Guzel N, "Effects of acute L-carnitine supplementation on nitric oxide production and oxidative stress after exhaustive exercise in young soccer players" 55 : 9-15, 2015

28 Spiering BA, "Effects of L-carnitine L-tartrate supplementation on muscle oxygenation responses to resistance exercise" 22 : 1130-1135, 2008

29 McBride JM, "Effect of resistance exercise on free radical production" 30 : 67-72, 1998

30 Barnett C, "Effect of L-carnitine supplementation on muscle and blood carnitine content and lactate accumulation during high-intensity sprint cycling" 4 : 280-288, 1994

31 Koc A, "Effect of L-carnitine on the synthesis of nitric oxide in RAW 264.7 murine macrophage cell line" 29 : 679-685, 2011

32 Vassalle C, "Determination of nitrite plus nitrate and malondialdehyde in human plasma : analytical performance and the effect of smoking and exercise" 40 : 802-809, 2002

33 Sachan DS, "Decreasing oxidative stress with choline and carnitine in women" 24 : 172-176, 2005

34 Morgan MJ, "Crosstalk of reactive oxygen species and NF-kappaB signaling" 21 : 103-115, 2011

35 Starkie RL, "Circulating monocytes are not the source of elevations in plasma IL-6 and TNF-alpha levels after prolonged running" 280 : C769-C774, 2001

36 Wall BT, "Chronic oral ingestion of L-carnitine and carbohydrate increases muscle carnitine content and alters muscle fuel metabolism during exercise in humans" 589 : 963-973, 2011

37 Cuevas MJ, "Changes in oxidative stress markers and NF-kappaB activation induced by sprint exercise" 39 : 431-439, 2005

38 Aebi H, "Catalase in vitro" 105 : 121-126, 1984

39 Takahashi M, "Carnitine determination by an enzymatic cycling method with carnitine dehydrogenase" 40 : 817-821, 1994

40 Broad EM, "Carbohydrate, protein, and fat metabolism during exercise after oral carnitine supplementation in humans" 18 : 567-584, 2008

41 Farruggia C, "Astaxanthin plays anti-inflammatory and antioxidant effects by inhibiting NFkB nuclear translocation and NOX2 expression in macrophages" 29 : 603-608, 2015

42 Lee BJ, "Antiinflammatory effects of L-carnitine supplementation(1000 mg/d)in coronary artery disease patients" 31 : 475-479, 2015

43 Kraemer WJ, "Androgenic responses to resistance exercise : effects of feeding and L-carnitine" 38 : 128896-, 2006

44 Pescatello LS, "American College of Sports, ACSM's guidelines for exercise testing and prescription" Wolters Kluwer/Lippincott Wil liams & Wilkins Health 2014

45 Schooneman MG, "Acylcarnitines: reflecting or inflicting insulin resistance?" 62 : 1-8, 2013

46 Berzosa C, "Acute exercise increases plasma total antioxidant status and antioxidant enzyme activities in untrained men" 2011 : 540458-, 2011

47 Constantin-Teodosiu D, "Acetyl group accumulation and pyruvate dehydrogenase activity in human muscle during incremental exercise" 143 : 367-372, 1991

48 Erel O, "A novel automated direct measurement method for total antioxidant capacity using a new generation, more stable ABTS radical cation" 37 : 277-285, 2004