Effect of novel dietary supplement on metabolism in vitro and in vivo

Abstract

Obesity is an increasingly prevalent and preventable morbidity with multiple behavioral, surgical and pharmacological interventions currently available. Commercial dietary supplements are often advertised to stimulate metabolism and cause rapid weight and/or fat loss, although few well-controlled studies have demonstrated such effects. We describe a commercially available dietary supplement (purportedly containing caffeine, catechins, and other metabolic stimulators) on resting metabolic rate in humans, and on metabolism, mitochondrial content, and related gene expression in vitro. Human males ingested either a placebo or commercially available supplement (RF) in a randomized double-blind placebo-controlled cross-over fashion. Metabolic rate, respiratory exchange ratio, and blood pressure were measured hourly for 3 h post-ingestion. To investigate molecular effects, human rhabdomyosarcoma cells (RD) and mouse myocytes (C2C12) were treated with various doses of RF for various durations. RF enhanced energy expenditure and systolic blood pressure in human males without altering substrate utilization. In myocytes, RF enhanced metabolism, metabolic gene expression, and mitochondrial content suggesting RF may target common energetic pathways which control mitochondrial biogenesis. RF appears to increase metabolism immediately following ingestion, although it is unclear if RF provides benefits beyond those provided by caffeine alone. Additional research is needed to examine safety and efficacy for human weight loss.

Effect of a Multi-Nutrient Over-the-Counter Supplement on Changes in Metabolic Rate and Markers of Lipolysis

“…While formulation differences certainly exist, the impact of epinephrine increases in the present study are an important mechanistic link to the reported increases in energy expenditure and oxygen consumption by the present study and the work of Vaughan et al (Vaughan et al, 2015). In light of our findings, it is tempting to speculate that the caffeine contained within the TS formulation was the primary contributor to the reported increases in oxygen consumption, epinephrine and energy levels in the present study, however, we acknowledge that our study was not designed to explicitly highlight the impact of any single ingredient, including caffeine.…”

“…A priori statistical power and sample size calculations were completed, but the measured effects were not as great as expected based on previous (similar) studies. For example, Vaughan et al, 2015 administered TS to ten healthy, collegeaged men and reported a significant increase in oxygen consumption, while the present study employed 15 participants, but failed to report any between-condition effects. This is largely due to the smaller measured effect in the present study versus the measured effects in the Vaughan paper.…”

“…Recently, Vaughan and colleagues published separate findings on the same dietary supplement formulation (i.e., TS) after employing both in vivo and in vitro models (Vaughan et al, 2015). Using a comprehensive in vitro model in a human rhabdomyosarcoma cell line and murine myocytes, these authors completed metabolic assays, messenger ribonucleic acid (mRNA) expression of metabolic genes, immunofluorescence and flow cytometry techniques to assess the impact of TS.…”

“…An a priori power analysis for this cross-over design indicated that a sample size of 15 participants and an anticipated increase in resting metabolic rate of 0.45 mL/kg/min would yield a power value of 0.80 with an alpha level of 0.05. In addition, our sample size was similar to the 2015 paper by Vaughan and colleagues that employed a similar study design with ten participants (Vaughan et al, 2015) who reported an increase in metabolic rate from TS ingestion.…”

“…Currently, limited human research is available on this formulation. Vaughan and colleagues recently published a paper in which they used in vitro and in vivo approaches to examine the impact of this formulation on various metabolic functions (Vaughan et al, 2015). The in vitro findings in human rhabdomyosarcoma cells and mouse myocytes reported an enhanced ability to stimulate metabolism and increase both metabolic gene expression and mitochondrial content.…”