This Month’s Featured Article:
Creatine monohydrate and conjugated linoleic acids sustain muscle mass and reduce body fat in the elderly.
by Alfredo Franco, PhD
Sarcopenia: Derived from the Greek words, Sarx (flesh) and Penia (loss). Sarcopenia literally describes the loss of muscle that occurs with advanced age.
Sarcopenia-Related Loss of Muscle Mass
Skeletal muscle is our most abundant tissue, comprising nearly half of our entire body mass as young adults. In later life, however, our ability to regenerate injured muscle decreases significantly. Moreover, because skeletal muscle is such an essential storage site for many of the body’s most important metabolites, sarcopenia increases the susceptibility of the elderly to infection and reduces their resilience to trauma. As the fraction of the world’s population that is over 65 years of age steadily increases (in the United States estimated to double in only 25 years), combating sarcopenia takes on an even-greater urgency in the global clinical stage.
Sarcopenia arises from a combined consequence of an age-related decline in anabolic hormone levels (testosterone, growth hormone and the insulin-like growth factors), reduced levels of physical activity due to accumulated trauma, or disease, and a reduction in the effectiveness of central nervous communication with the peripheral musculature. At the biochemical level, sarcopenia is characterized by a decrease in the rate at which new proteins are synthesized, concomitant with an increased rate of protein degradation. In other words, the elderly usually destroy more proteins than they are able to produce, a clinical scenario that is even more devastating following injury, which requires a robust response of protein synthesis. This extent of this effect is compounded by evidence indicating a reduction in the effectiveness of muscle regeneration following injury, implicating insufficiencies in the aging muscle stem cell pool. Increased levels of proinflammatory cytokines and reactive oxygen species have also been correlated with the development of sarcopenia. Finally, metabolic deficiencies and a decreased capacity of the liver for detoxification have also been associated with the appearance of sarcopenia. Although all these factors will contribute to the development of sarcopenia, the characteristic age-related decline in anabolic hormone levels is the most decisive in determining the time course of its appearance. Generally, the rate of overall muscle loss is between 1% and 2% per year after the fifth decade of life.
Sarcopenia specifically depletes our fast muscle fiber pool. Fast muscle fibers are also those that respond most robustly to creatine supplementation. By inference therefore, creatine supplementation, by supporting the survival of fast muscle fibers, should help counteract some of the degenerative effects of sarcopenia.
Please refer to our page discussing the positive influence that creatine supplementation might play in maintaining youthful anabolic hormone levels into advanced age.
Also visit our Creatine and the Elderly page.
Sarcopenia-Related Increase of Body Fat
Sarcopenia also has a tendency to increase the size of our extramuscular fat reserves. In other words, fat often appears in regions of lost muscle in later stages of sarcopenia.
Obesity is associated with increased levels of markers for inflammation. These same markers are also detected in response to prolonged inactivity as well as in the elderly. This relationship between obesity and sarcopenia appears to be more causative than casual. Specifically, obesity feeds-forward the development of sarcopenia in two ways: 1) fat is a major source of proinflammatory cytokines, such as TNF-alpha and; 2) obese individuals are generally less active, which accelerates the onset of sarcopenia. Importantly, TNF-alpha counteracts the anabolic effects of IGF-1, one of our most important myogenic growth factors. These apparently separate processes are intertwined, however, as physical activity stimulates IGF-1 production, albeit to a reduced degree in the elderly. The result is that IGF-1 levels decrease with advanced age.
Again, IGF-1 is one of our most essential pro-anabolic, anti-catabolic, growth factors and circulating levels of IGF-1 decrease with age – largely contributing to sarcopenia. Interestingly, creatine supplementation activates many of the same biochemical pathways that IGF-1 does in order to promote protein synthesis and slow protein degradation. This important attribute of creatine supplementation will be the topic of a subsequent issue of the Creatine Newsletter.
Read about the potential for creatine supplementation to sustain IGF-1 expression levels into later life and hence, slow the progression of sarcopenia.
Conjugated Linoleic Acids Reduce Body Fat
Obviously, fat accumulation aggravates sarcopenia. Conjugated linoleic acids have been shown in scientific studies to promote fat loss in overweight individuals, particularly in the abdominal area. This is an important finding given that higher amounts of abdominal fat are strongly correlated with the incidence of cardiovascular disease. Conjugated linoleic acids have also been shown to favorably alter serum lipid levels, reduce whole body glucose uptake and regulate energy metabolism. Conjugated linoleic acids have also been shown to possess anticarcinogenic properties. Conjugated linoleic acids thus help reverse several risk factors of diseases associated with advanced age.
Meat and dairy products obtained from grassfed animals are a very rich source of conjugated linoleic acids. Adverse side effects appear to be minimal following dietary supplementation with conjugated linoleic acids.
Highlighted Scientific Study
Creatine monohydrate and conjugated linoleic acid improve strength and body composition following resistance exercise in older adults.
Tarnopolsky, M. et al. (2007) PLoS ONE, Volume 2 (10), pages e991.
Thirty nine subjects (20 men and 19 women) between the ages of 65 and 85 years of age participated in the study. Subjects either consumed one of two drinks, creatine monohydrate (5 grams/day) plus conjugated linoleic acids (6 grams/day) or placebo (dextrose and safflower oil) while undertaking six months of moderate resistance training (2 days per week). Measures of body composition and physical performance were compared before and after the training period of six months.
AUTHOR’S NOTE: The amount of creatine administered in this study is relatively moderate, only 10% to 20% of that taken by athletes during a typical loading phase. I personally agree with this approach with respect to anyone over 40 years of age.
The best way to calculate a creatine dose to fit your particular needs is explained in Creatine: A practical guide. Learn more about this informative fitness guide.
Results of the Study
As expected from previous studies physical performance improved following creatine supplementation, in particular, muscular endurance was enhanced. Also anticipated from previous studies was the fact that the amount of lean (fat free) muscle mass increased in subjects who had supplemented with creatine. That is, the ratio of muscle to muscular fat (and water) increased in response to creatine ingestion, a well-established fact.
On the other hand, it is not expected that creatine supplementation (in conjunction with moderate resistance exercise) should reduce the size of the fat reserves that lie outside of muscle. Dr. Mark Tarnopolsky and colleague previously established an absence of a direct effect of creatine supplementation on total body fat content. Dr. Tarnopolsky is one of the contributors (authors) of the study we are discussing today.
The addition of conjugated linoleic acids to the supplementing regimen, however, did appear to reduce total body fat content, which agrees with previous studies showing that these essential fatty acids promote fat loss in overweight individuals.
The study was thoroughly conducted. Most indicators of general health and cellular damage were within normal limits following supplementation with creatine and conjugated linoleic acid and these did not significantly change in response to training. The single exception to this trend was for a marker of DNA oxidative stress, 8-OH-2-dG, which was reduced in the supplementing group, suggesting that oxidative stress is mitigated by creatine supplementation. This is good news given that exercise may augment oxidative stress, which, in turn, damages our DNA, destroys our lipid membranes, and irreversibly renders proteins nonfunctional as well as nondegradable. The combination of these effects hampers muscle function and causes accumulative damage to our muscles. Oxidative stress also stimulates the production of the proinflammatory cytokines, which augment muscle catabolism (breakdown).
Only minor side effects were observed, with only one incidence of gastrointestinal distress reported that did not lead to discontinuance of the study. Importantly, no signs of abnormal renal stress were observed in these elderly subjects.
This study indicates that combining creatine monohydrate and conjugated linoleic acids may help counteract two of the more damaging consequences of sarcopenia: 1) the loss of lean muscle mass and; 2) the increase in total body fat. Reductions in muscle mass reduce our mobility, compromise our independence as well as makes us more vulnerable to injury and disease. Increase in body fat content, on the other hand, increases the risk of cardiovascular disease, which, in turn, aggravates the loss of muscle mass.
The results from this study are not unique, however, but have been corroborated by many previous studies on a variety of age groups. The importance of this study lies in the novel combination of creatine and conjugated linoleic acid and its implication that such a supplementing regimen in the context of moderate resistance exercise can improve the quality of life and longevity of individuals beyond their fifth decade of life.
View all past issues of the Creatine Newsletter.
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