Effects of Coffee Components on Muscle Glycogen Recovery: A Systematic Review

Abstract

Coffee is one of the most consumed beverages in the world, and it can improve insulin sensitivity, stimulating glucose uptake in skeletal muscle when adequate carbohydrate intake is observed. The aim of this review is to analyze the effects of coffee and coffee components on muscle glycogen metabolism. A literature search was conducted according to Preferred Reporting Items for Systematic Reviews and Meta-Analysis, and seven studies were included, that explored the effects of coffee components on various substances and signaling proteins. In one of the studies with humans, caffeine was shown to increase glucose levels, Ca/calmodulin-dependent protein kinase phosphorylation, glycogen resynthesis rates, and glycogen accumulation after exercise. After intravenous injection of caffeine in rats, caffeine increased adenosine monophosphate-activated protein kinase (AMPK) and acetyl-CoA carboxylase (ACC) phosphorylation, and glucose transport. In in vitro studies, caffeine raised AMPK and ACC phosphorylation, increasing glucose transport activity and reducing energy status in rat muscle cells. Cafestol and caffeic acid increased insulin secretion in rat beta cells and glucose uptake into human muscle cells. Caffeic acid also increased AMPK and ACC phosphorylation, reducing the energy status and increasing glucose uptake in rat muscle cells. Chlorogenic acid did not show any positive or negative effect. The findings from this review must be taken with caution due to the limited number of studies on the subject. In conclusion, various coffee components had a neutral or positive role in the metabolism of glucose and muscle glycogen, whereas no detrimental effect was described. Coffee beverages should be tested as an option for athletes' glycogen recovery.

Caffeine and Exercise: What Next?

“…Aside from affecting sleep, caffeine may also modify post-training and competition recovery. In a recent review, Loureiro and colleagues [ 49 ] reported conflicting data regarding the effects of caffeine on muscle glycogen recovery, suggesting a need for further research in this area. Interestingly, cafestol and caffeic acid—ingredients of coffee—appear to enhance muscle glycogen recovery [ 49 ], suggesting that the use of coffee as a means to receive caffeine pre-exercise may confer some additional benefits compared to other caffeinated mediums.…”

“…In a recent review, Loureiro and colleagues [ 49 ] reported conflicting data regarding the effects of caffeine on muscle glycogen recovery, suggesting a need for further research in this area. Interestingly, cafestol and caffeic acid—ingredients of coffee—appear to enhance muscle glycogen recovery [ 49 ], suggesting that the use of coffee as a means to receive caffeine pre-exercise may confer some additional benefits compared to other caffeinated mediums. In another review [ 20 ], the authors concluded that caffeine ingestion prior to resistance training may reduce the occurrence of delayed onset of muscle soreness, recommending further research to explore this.…”

Is Coffee a Useful Source of Caffeine Preexercise?

“…Additionally, a recent review (Loureiro et al, 2018) examined whether coffee components, primarily caffeine, caffeic acid, cafestol, and chlorogenic acid, may exert beneficial effects on muscle glycogen recovery post-exercise. Whilst the studies underpinning this review were primarily conducted in vitro or in rats, this is an area worthy of potential exploration, particularly if coffee outperforms caffeine anhydrous in this regard.…”

What Should We Do About Habitual Caffeine Use in Athletes?

“…Recently, the availability of caffeine-containing supplements, including tablets and energy drinks, has likely contributed to increased caffeine intakes in non-athletes and athletes [ 35 ]. The majority of these caffeine sources also include other compounds with potential positive effects, such as taurine in energy drinks (performance enhancement [ 36 ]), and both chlorogenic acid (health benefits [ 37 ]) and caffeic acid (promotion of post-exercise glycogen synthesis [ 38 ]) in coffee.…”