Creatine

Creatine is one of the most popular supplements among athletes. Studies have consistently shown that creatine supplementation increases intramuscular creatine concentrations, improving exercise performance and/or enhancing training adaptations. Research has also indicated that creatine supplementation may improve post-exercise recovery and may help with injury prevention, thermoregulation, rehabilitation, and neuroprotection in cases of concussion and/or spinal cord injury. Several clinical applications of creatine supplementation have also been investigated, particularly in relation to neurodegenerative diseases (e.g., muscular dystrophy, Parkinson's disease, and Huntington's disease), diabetes, osteoarthritis, fibromyalgia, aging, cerebral and cardiac ischemia, adolescent depression, and pregnancy. The most commonly studied form of creatine in the literature is creatine monohydrate. The uptake of creatine first involves its absorption into the bloodstream and subsequently its uptake by target tissues. Plasma creatine levels typically peak about 60 minutes after the oral ingestion of creatine monohydrate. An initial increase in plasma creatine levels, followed by a reduction, can indirectly suggest increased creatine uptake by target tissues. However, in recent years, new formulations of creatine have been developed to improve its solubility, stability, or bioavailability. Therefore, it is of interest to evaluate whether these formulations differ in absorption kinetics from creatine monohydrate, the reference form in the literature. The aim is to compare the blood absorption of a new formulation of creatine (containing Creatine Phosphate, Creatine Pyruvate, Creatine Hydrochloride) with that of traditional creatine monohydrate. It is hypothesized that the new formulation has a pharmacokinetic profile similar to that of creatine monohydrate.

This study will be a randomized, double-blind, placebo-controlled trial. It will be conducted over a 8-week intervention investigating the effects of creatine (5g Creatine monohydrate); placebo control (5g resistant dextrin), and a combination group containing both creatine and tyrosol (5g creatine monohydrate + 150mg tyrosol/day). Endurance, strength, cognition, and fatigue resistance will be examined through repeated strength and endurance testing (described below). Participants who pass initial screening will be invited on-site for day one (Visit 1) of testing where the participants will proceed with a series of tests which will include the following: (1) body composition; (2) mood and cognitive testing; (3) full-body strength testing; (4) 5RM (repetition maximum) bench press, leading to multiple sets of bench press (based on the previous weight) completed to failure; (5) finally, a time to exhaustion endurance test will be conducted followed by (6) repeat cognitive testing. After the 8-week supplementation period (\~56-60 days), all original measures will be repeated as before in the same order (Visit 2). Approximately 24 hours later (Visit 3) participants will complete a questionnaire for muscle soreness remotely, and again at 48 hours post-Visit 2 (visit 4).

The goal of this 26-week trial is to learn if creatine supplementation and resistance training (i.e., weightlifting; exercise that increases muscle mass), alone and together, impact cognition, brain health, and physical function in older adults with mild cognitive impairment. Previous studies have shown that resistance training improves cognition and brain health in older adults. Creatine is naturally occurring in the human body and is known to decline with age. Studies have shown that creatine increases muscle mass and bone density in older adults when supplemented. Some research has suggested that creatine may also improve cognition and brain health. However, little is known about how creatine supplementation affects the aging brain and body alone and when combined with resistance training, especially in those with known cognitive impairment. In this study, participants will be randomly assigned to one of four groups: 1) creatine and resistance training, 2) placebo and resistance training, 3) creatine and active control (balance and tone classes), or 4) placebo and active control. Participants in the creatine groups will take creatine every day during the study. Participants in the placebo groups will take a look-alike substance that contains no drug every day during the study. Participants in the resistance training groups will attend three 60-minute classes per week that target each major muscle group and will increase in difficulty during the study. Participants in the active control group will attend three 60-minute classes per week that will consist of balance, stretching, and range of motion exercises. This group accounts for variables such as physical training received by traveling to the training centres, social interaction, and changes in lifestyle secondary to study participation. Researchers will collect information before and after the 26 weeks to see if creatine supplementation and/or resistance training have any effects on cognition, brain health, and/or physical function. The investigators suspect that both creatine supplementation and resistance training will improve cognition, brain health, and physical function alone. However, it is thought that the combination of creatine supplementation and resistance training will improve cognition, brain health, and physical function more.