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

Abstract

BackgroundProgressive decline in skeletal muscle mass and function are growing concerns in an aging population. Diet and physical activity are important for muscle maintenance but these requirements are not always met. This highlights the potential for nutritional supplementation. As a primary objective, we sought to assess the effect of a novel combination of L-Carnitine, creatine and leucine on muscle mass and performance in older subjects.MethodForty-two healthy older adults aged 55–70 years were randomized to receive either a novel L-Carnitine (1500 mg), L-leucine (2000 mg), creatine (3000 mg), Vitamin D3 (10 μg) (L-Carnitine-combination) product (n = 14), L-Carnitine (1500 mg) (n = 14), or a placebo (n = 14) for eight weeks. We evaluated body mass by DXA, upper and lower strength by dynamometry, and walking distance by a 6-min walk test at baseline and after eight weeks of intervention. These measures, reflecting muscle mass, functional strength and mobility have been combined to generate a primary composite score. Quality of life, blood safety markers, and muscle biopsies for protein biomarker analysis were also conducted at baseline and the end of the study.ResultsThe primary composite outcome improved by 63.5 percentage points in the L-Carnitine-combination group vs. placebo (P = 0.013). However, this composite score did not change significantly in the L-Carnitine group (P = 0.232), and decreased slightly in the placebo group (P = 0.534). Participants supplemented with the L-Carnitine-combination showed a 1.0 kg increase in total lean muscle mass (P = 0.013), leg lean muscle mass (0.35 kg, P = 0.005), and a 1.0 kg increase in lower leg strength (P = 0.029) at week 8. In addition, these increases were significant when compared to the placebo group (P = 0.034, P = 0.026, and P = 0.002, respectively). Total mTOR protein expression was increased in participants in the L-Carnitine-combination group at the end of the study compared to the baseline (P = 0.017). This increase was also significant when compared to the placebo (P = 0.039), suggesting that the increase in muscle mass and strength was due to new protein synthesis and mTOR pathway activation.ConclusionsThe trial did reach its primary objective. L-Carnitine combined with creatine and L-leucine significantly improved the composite score which reflects muscle mass and strength, at the end of the study compared to placebo. The combination showed an increase in mTOR protein level, a driver for increased muscle mass which translated to an improvement in muscle strength. This new combination may provide a potential nutritional intervention to promote muscle growth and improved physical functioning in older adults.Electronic supplementary materialThe online version of this article (doi:10.1186/s12986-016-0158-y) contains supplementary material, which is available to authorized users.

Effect of creatine supplementation during resistance training on lean tissue mass and muscular strength in older adults: a meta-analysis

“…After the review of abstracts, 26 full-length manuscripts were retrieved. Three manuscripts were excluded because they involved interventions of creatine supplementation without resistance training, 18 – 20 and one study presented lean tissue mass and strength results from the same participants across two manuscripts; 21 , 22 therefore, 22 unique studies were included. Of these studies, five combined creatine supplementation with other nutritional supplements (ie, protein or conjugated linoleic acid).…”

“… 87 These pathways involved in translation may be negatively affected by aging. 88 The total amount of mTOR is upregulated in older adults when a nutritional supplement containing creatine is consumed; 20 however, there was no effect of creatine on the phosphorylation (ie activation) of mTOR or other components of the translation-signaling pathway. The nutritional supplement used in this study also contained additional components besides creatine (ie, L-carnitine, leucine, and vitamin D); thus, the direct effect of creatine could not be determined.…”

The bright and the dark sides of L-carnitine supplementation: a systematic review

“…Various effects might be due to different IGF-1 levels; significantly lower in the HIV-seropositive patients than in healthy subjects [ 38 ]. Additionally, 8 weeks of LC supplementation in healthy older subjects, did not change total and phosphorylated mTOR, S6K and 4E-BP proteins level of vastus lateralis muscle [ 39 ]. It must be highlighted that rat skeletal muscle TC increases ~ 50–70% following 4 weeks of LC supplementation [ 33 , 34 ], whereas comparable elevation has never been observed in human studies, even after 24 weeks of supplementation [ 5 , 7 ].…”

Effect of Schisandra chinensis Extract Supplementation on Quadriceps Muscle Strength and Fatigue in Adult Women: A Randomized, Double-Blind, Placebo-Controlled Trial

“…Maintaining a high level of muscle strength can be an important means of preventing frailty and hospitalization, as well as physical disability and function limitation in IADLs [11,12,32,33]. Adequate nutritional supplementation is an important element of any strategy for the preservation of skeletal muscle mass, muscle strength, and muscle protein synthesis during aging [34][35][36]. SC is one of the most well-known herbal medicines and has been extensively used in Asia, including Japan, China, and Korea [37].…”