It is important to recognize that not everything is acceptable in sports nutrition. In a growing market of supplements and discount codes, commercial interests sometimes take precedence over truth and scientific evidence. This creates a strange landscape in which most commercial products do not need to demonstrate effectiveness and do not do what they claim or promise.
Creatine monohydrate, however, is one of the few supplements supported by solid evidence for effectiveness, safety and legality. Most of us know its roles in energy production and the resulting performance improvements through multiple mechanisms (Figure 1).
Figure 1. Creatine's mechanism of action and main adaptations to resistance training.
Creatine is currently one of the most popular ergogenic nutritional aids for athletes—or it should be. Studies consistently show that creatine-monohydrate supplementation increases intramuscular creatine concentrations, helping explain observed improvements in high-intensity exercise and greater training adaptations (Figure 1).
Creatine is well known for its roles in sport, but less so in clinical settings and particularly for its important brain and cognitive roles, which this article discusses among other topics.
Both endogenous and dietary creatine are transported through the bloodstream to other organs, including skeletal muscle, the heart and the brain. Most creatine in the body is absorbed and used by skeletal muscle, while only a small portion is absorbed by the brain.
Brain uptake of creatine is much slower than skeletal-muscle uptake, suggesting that the blood-brain barrier hinders transport. Protocols intended to increase brain creatine may therefore require higher doses and/or longer use than the conventional protocol of 0,07g/kg.
Once in the brain, creatine is used in the same way as in the heart and muscle to produce ATP. Oral creatine supplementation increases its physiological concentration in the brain, raising PCr levels.
Cognitive deficits have been associated with inherent reductions in brain creatine. Increased oral supplementation has been shown to replenish brain creatine levels successfully and could theoretically reverse these cognitive deficits (Figure 2).
Figure 2. Potential therapeutic effects of creatine in the brain.
Increasing oral creatine supplementation may improve brain function, working memory and recognition memory while reducing mental fatigue. These positive effects and other cognitive properties are thought to result from greater creatine availability in the brain.
According to the latest evidence, most supplementation effects appear more relevant under acute stress—mental fatigue, sleep deprivation or exhaustive exercise—or chronic stress, including aging, depression and post-traumatic stress disorder. Creatine may even exert a neuroprotective effect in athletes at greater risk of head trauma, such as those in contact and team sports, while effects are absent or minimal in healthy individuals without these stress conditions.
Another recent and interesting area of study is creatine monohydrate for preventing sarcopenia, loss of bone mineral density and inflammation in older adults.
Sarcopenia, considered a disease by the WHO, is an age-related muscle condition affecting 8-13% of adults > 60 years. It is characterized by reduced muscle quantity, muscular strength—dynapenia—and physical performance, meaning functional tasks. It is also associated with higher mortality and multiple comorbidities, including frailty, greater risk of falls and fractures, disability and cachexia.
Sarcopenia is multifactorial and may be caused by changes in muscle morphology, muscle-protein kinetics, neuromuscular function, inflammation, physical activity and nutrition.
Much attention has focused on nutritional interventions as a potential therapeutic approach. Consuming creatine with or without resistance training—although energy balance, protein amount and resistance training are far more important—has been associated with increased muscle mass and function in older adults.
Creatine may influence ATP metabolism and increase calcium uptake in the sarcoplasmic reticulum, reducing muscle-relaxation time and increasing force development while improving muscle-protein kinetics and factors such as inflammation.
Regarding inflammation, the biological aging process is proposed to involve inherent mitochondrial damage combined with elevated, sustained low-grade inflammation. This impairs the electron-transport chain and negatively affects muscle and bone tissue, leading to overproduction of reactive oxygen species. These ROS can cause mutations in mitochondrial DNA, damage and alter cell membranes, and promote inflammation, muscle damage and muscle-protein breakdown.
Through its antioxidant role, creatine supplementation may help mitigate mitochondrial damage, thereby reducing oxidative stress, cellular apoptosis and low-grade inflammation.
Response to creatine supplementation varies greatly among older adults. Initial intramuscular PCr concentration, type II muscle-fiber content and size—which decline with age—and habitual dietary creatine intake may explain inconsistent findings across studies. Older populations also tend to consume somewhat less dietary protein.
Other recent studies focus on creatine supplementation for improving bone mineral density, although only some trials support this. The proposed explanation involves activation of cells involved in both bone formation and resorption. Creatine could also potentially reduce older adults' risk of falls, thereby reducing fracture risk.
Although there is not yet enough evidence to confirm these latest findings, creatine's established safety during chronic consumption in healthy populations—including renal and hepatic safety—and its many other mechanisms of action not discussed here (Figure 3) make older adults one of the target populations for whom this ergonutritional aid may be most relevant.
Figure 3. Other potential functions of creatine.
BIBLIOGRAPHY
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AUTHOR
Marcos Rueda Córdoba
- Degree in Human Nutrition and Dietetics (UGR) and official master's degree in Nutrition for Physical Activity and Sport (UCAM). ISAK Level I anthropometrist, creator of specialized sports-nutrition content and courses delivered online and in person, and lecturer at Grupo San Valero (San Jorge University, Zaragoza).
- In-person nutrition consultations in Granada and online.
