Written by: Aaron Riviere, Dietetic Intern Texas A&M University
Edited by: Brett Singer MS,RD,CSSD,LD; Sports Dietitian Memorial Hermann IRONMAN Sports Medicine Institute
SUMMARY:
Creatine is often seen as a supplement for bodybuilders and people looking to max out their muscle gains in the gym, but creatine can be beneficial for a variety of people. One population of recent interest is aging adults (55+) because of their risk of sarcopenia, the accelerated loss of muscle mass and function associated with aging. Sarcopenia often leads to a decreased quality of life and increased risk of injury and mortality1. There are many therapeutic options available to reduce the rate of sarcopenia, but resistance training is often prescribed to improve or delay muscle loss and decreased function in older adults2. While creatine is an evidence-based supplement to optimize benefits of resistance training in young adults, the benefit for older adults is under investigation.
The body uses creatine for increased energy in short duration events. Creatine is converted to phosphocreatine and reconverted back to creatine in order to maintain creatine and ATP levels in the muscle. There is some creatine loss through urine, which needs to be replaced through the diet or made by the body. Our diet provides about half of the creatine the body needs to replenish, about 1-2 grams per day from meat products. The other half comes from our body breaking down proteins to build creatine. These two sources lead to creatine muscle stores that are 60-80% full3. A common way to increase creatine stores further is through creatine supplementation4, 5. The protocol is 20g/day dose for 5-7 days with a continued dose of 3-5g/day to maintain levels3. Creatine has been proven to be safe for most populations, up to 30g/day, except for individuals with kidney disease3, 6.
Most research projects are focused on the benefits of creatine supplementation in younger adults, but older adults can see similar or greater improvements in muscle creatine saturation after supplementation5. This may be from lower dietary creatine intake, changes in muscle physiology resulting from aging, or other reasons that need to be explored7. Though supplementation can increase muscle creatine stores, having increased levels alone may not provide a significant benefit to older adults.
Studies have shown mixed results on creatine supplementation without resistance training on muscle mass or strength. One study by Gualano et al. showed that there was less muscle loss in the creatine supplementation group (5g/day) compared to the placebo group in older women when neither group performed resistance exercises8. This research group repeated this experiment with 3g/day and 1g/day doses at longer time intervals and found no effects9, 10. There needs to be further research looking at dosage and time of creatine alone, but it may be most beneficial when paired with resistance training.
Resistance training is a common therapy for lowering the risk and decline of sarcopenia. Multiple studies have looked at creatine supplementation in older adults when performing resistance exercises. Two meta-analyses by Candow et al. and Forbes et al. showed that supplementation of creatine improves muscle mass, upper body strength, and lower body strength in older adults, though they recognize high inter-individual responses to supplementation11, 12. Forbes et al. further looked at supplementation protocols required for the gains in mass and upper body and lower body strength. They showed that both a high creatine dose, 5g/day or 0.1g/kg/day, or a low creatine dose, 1g/day, was beneficial for lean muscle mass gains. A higher dose or low dose with creatine loading, 20g/day for 5-7 days, was needed for chest press strength increases and only high doses with a loading phase showed improved leg press strength. They also found that taking creatine only on days with resistance training still had significant benefits12. Overall, this meta-analysis suggests a loading phase (20g/day for 5-7 days) with high daily doses (5g/day) has the best benefit for muscle mass gain and total body strength increases.
For older adults, increasing bench press or having more muscle mass alone may not be the goal of resistance training. Many older adults are looking to preserve strength, muscle mass, and overall quality of life. There are fewer studies measuring improved daily movements. Candow et al. evaluated 6 studies that have measured the sit-to-stand test and 2 studies that measured a timed up-and-go test. The sit-to-stand test is the time for an individual to go from a seated position to a standing position and back to a seated position a set number of times. The timed up-and-go test measures the time an individual can stand up from a chair, walk three meters, turn around, and walk back to the chair and sit down. Both of these tests are used as measures of functional movement in older adults. These studies showed a significant improvement in the sit-to-stand test but no effect of creatine on the timed up-and-go test11. These studies show improvement in markers that represent better function day-to-day, but do not measure actual functional movement in a real-life setting or quality of life. Further studies that measure long-term fall risk, range of motion while maintaining strength, reduced need for walkers or canes, and quality of life are all areas that could be further explored to find clinically and daily relevant improvements for aging adults.
There is a fair amount of research to show the potential benefits of creatine supplementation with resistance training in older adults, but there are still multiple factors that need to be explored to find the need and overall value of creatine. Creatine requires multiple amino acids and enzymes to be produced and can be taxing on the levels in the body. Older adults have decreased amino acid intake and have high vitamin B12 deficiency rates, which may reduce creatine production13, 14. Protein supplementation is beneficial for strength and muscle mass gains in older adults15. When creatine is added to protein supplementation, it may not provide an added benefit to whey protein alone16,17. These studies show that protein intake, creatine dosing, and other nutritional factors play a role in creatine’s effects.
Another limiting factor for creatine research is the limited clinically relevant markers. Many older adults may care more about maintaining functional status that is lost with sarcopenia than maximizing muscle mass or improving their one-rep max in leg press or bench press. More research is needed on whether creatine supplementation has clinically significant improvements when compared to resistance training alone. Since there are many factors that influence creatine’s effectiveness, different individuals can have very different responses to creatine as shown in a meta-analysis by Chilibeck et al. Their analysis showed 10 studies with no effects of creatine supplementation while the other 12 showed positive benefits. These studies had a variety of doses, loading phases, and dietary assessment18.
As an older adult who performs resistance exercises, creatine is a safe supplement that can have a positive impact on strength and gaining lean mass. The best dosing protocol for older adults is a 20g/day loading phase for 5-7 days with a daily dose of 5g/day18. Though there is still more evidence needed for a full understanding, creatine is a relatively cheap and safe supplement that also is being investigated for neurological benefits in other disease states that could benefit older adults specifically3.
Have questions or want to set up a consultation? Please contact Memorial Hermann IRONMAN Sports Medicine Institute Sports Dietitian Brett Singer at brett.singer@memorialhermann.org. or by phone at (713) 526-6143.
You can also follow him on twitter @bsinger10 or on Instagram @bsinger_sportsrd.
REFERENCES
1. Tsekoura, M., et al. Sarcopenia and Its Impact on Quality of Life. 2017. Cham: Springer International Publishing.