11. Creatine risks and side effects?
12. Long-term consequences of creatine use?
13. Does creatine cause cancer?
14. Can creatine help those with Muscular Dystrophy?
The creatine field has principally concentrated on male subjects between the ages of 18 and 35 years, a trend that is common in the sports medicine and exercise physiology fields. Scientific studies conducted on this age group have typically demonstrated enhancements in physical performance during repeated bouts of maximal effort, particularly during later repetitions when the accumulation of lactic acid becomes appreciable. Therefore, one of the major ergogenic benefits of creatine supplementation is to lessen the buildup of lactic acid and as a result, to prolong exercise output by offsetting the onset of muscle fatigue. Other contributions of creatine to the total ergogenic package have been discussed previously and have to do with creatine’s stockpiling effect over the cell’s anaerobic energy reserves (ATP and Phosphocreatine; see “How creatine works“), muscle cell proliferation and increases in the production of contractile and metabolic (energy-producing) proteins (see “How does creatine cause muscle growth“).
Although, the effects of creatine in children, the elderly and women has been studied much less, there is no a priori reason to think that creatine’s basic mechanism of action should differ with age or gender. However, subtle differences may exist in how creatine supplementation affects these distinct groups and special considerations may thus apply. That, is some aspects of creatine supplementation in these populations may be detrimental and present a valid basis for concern, whereas others may render a clear benefit. These considerations will be discussed below.
Whether creatine is safe for children is one of the questions that is most frequently submitted to this website. Most creatine experts are of the opinion that it is best to postpone creatine supplementation until after puberty, particularly since the long-term consequences of creatine supplementation are still largely unknown. In other words, if adverse consequences to creatine supplementation do exist, then the younger an athlete starts the practice, the more likely potential side effects are to manifest within their lifetime. Moreover, it has recently come to light that creatine influences cell metabolism and anabolism in ways never before suspected. It is unclear, at least to me, if such changes in cellular biochemistry are harmful to young developing bodies.
A more pertinent question might be: “Should children push themselves beyond the normal limits of play?” Remember, creatine supplementation primarily enhances an athlete’s ability to generate near maximal force during repetitive bouts of intense exercise. Given that some experts have warned that excessive mechanical stress might have deleterious consequences on a skeletal frame that is rapidly growing, I would advise against creatine supplementation before reaching puberty. This is just my personal opinion, the opinion of some experts may differ, and does.
Creatine studies conducted on adolescents have given both positive and null results creating a bit of confusion in the field. The simple truth is that too few studies exist to objectively state just how great an effective creatine supplementation has in the adolescent population. “Nonresponders” are observed even in the most heavily studied age group (18-35 years of age) and hence, the statistical uncertainty may merely reflect the fewer number of studies conducted on adolescents (see also “Does everyone respond to creatine?“).
Our muscular phosphocreatine levels decline in old age, partially explaining the decrease in strength and predisposition to fatigue observed in the elderly. Creatine supplementation might therefore prove especially worthwhile in the individuals over 50 years of age. In support of this notion several recent studies have demonstrated performance enhancement in healthy individuals in their 50s, 60s and early 70s. Importantly, creatine supplementation produces relatively greater gains in middle-aged subjects than in younger subjects.
Oddly, an effect of creatine supplementation (over physical performance) in individuals in their late 70s and 80s has been somewhat harder to resolve. Age-related decreases in activity-level, anabolic hormones, or type II (fast) muscle mass may all contribute to the reduced responsiveness of the elderly to creatine supplementation. Foremost, since type II muscle is the class of muscle fiber that is most responsive to creatine supplementation, a selective loss of this muscle class can largely account for the “apparent” insensitivity of elderly subjects to acute (one time) creatine supplementation (also see Question #5).
The elderly, however, are not without recourse in reversing this age-related decline in creatine responsiveness. For instance, regular exercise and eating a balanced diet helps maintain more youthful anabolic hormone levels in later life and hence, would serve to preserve one’s sensitivity to creatine. Maintaining an active lifestyle also would also help to prevent losses of existing muscle tissue, which would also translate into greater responsiveness to creatine supplementation. Therefore, exercise and good nutrition (in addition, to slowing the normal aging process) should prolong one’s sensitivity to creatine for longer in life. The increase in exercise output afforded by creatine supplementation, in turn, would further augment muscle anabolism and help offset the development of insulin resistance – in essence, feeding forward the maintenance of muscle mass and fending off fat accumulation in senior citizens.
On the other hand, recent evidence is now indicating that creatine supplementation per se helps maintain anabolic hormone levels and type II muscle mass – independently of broader lifestyle changes. Therefore, creatine supplementation may act directly to slow physical aging and hence, maintain its physiological relevance. Visit our Creatine and Sarcopenia page for more details about this intriguing attribute of creatine supplementation.
Clearly, creatine supplementation is a worthwhile endeavor in later life. Many aspects of creatine supplementation may prove particularly beneficial for older athletes. For instance, creatine supplementation may reduce the chances of developing coronary heart disease as well as several neurological disorders that plague the elderly. Visit our Creatine and the Senior Athlete page for more information about the possible benefits of creatine supplementation for elderly athletes.
Methylation status is an important contributing factor to the natural decline in strength and mental capacity associated with advanced age. It is now widely accepted that many of the devastating loses in mental and physical capacity that were once thought to be unavoidably linked to the normal aging process are, in fact, now known to be the result of an aged-related decline in methylation capacity. Creatine: A practical guide provides an easy to implement vitamin strategy that together with creatine supplementation will greatly promote your body’s methylation status, thereby greatly improving your overall health and increasing your gains in athletic performance. In fact, in a recent study that followed the health indices of 80,000 women for 14 years found that the incidence of heart attack was lowest in those utilizing a similar vitamin regimen (also see our Creatine and Coronary Heart Disease page).
If you should opt to supplement with creatine, make sure to use only the highest grade creatine products, an important measure since many of the less expensive brands of creatine contain significant quantities of potentially harmful contaminants. Get a free version of the Creatine Products Review explaining the formulations (and myths) behind some of the more popular creatine products currently on the market.
Creatine: A practical guide provides a supplementing regimen specifically designed for the special needs of the elderly.
Creatine: A practical guide also details other potential benefits of creatine supplementation for the elderly population, including a possible role for creatine in combating osteoporosis.
Several recent studies have examined the effects of creatine supplementation in women of diverse fitness levels. These studies have shown that although creatine enhances exercise performance in women, the effect was smaller than that observed in males participating in the same study. Specifically, gender differences were observed at the level of muscle protein turnover; creatine supplementation appears to have a greater anti-catabolic action in males. The higher resting levels of testosterone in males may underlie this distinct response of females to creatine supplementation.
It is not known whether the levels of creatine in breast milk increase during periods of supplementation. Until this information becomes available women nursing infants are advised to abstain from using creatine. The point of this recommendation is to avoid inadvertently exposing the infant to abnormally elevated levels of creatine that might alter key metabolic processes during development.
A red flag, however, was raised by studies examining rat fetal development. A region of the placenta known as the decidua was found in rodents to express very high levels of the enzyme, AGAT (L-Arginine:GlycineAmidinoTransferase). AGAT is first of two enzymes used in the synthesis of creatine from common amino acids. AGAT catalyzes the union of arginine and methionine to form GuanidinoAcetic Acid, or GAA, in the kidneys; ornithine is the other product of this synthetic reaction. GAA is then transported in the blood stream to the liver where it is activated by the addition of a methyl group (from methionine) to produce creatine. This second step is one of the principal methylation reactions undertaken by the body.
See the creatine synthetic reaction in full detail.
Most importantly, the expression of AGAT has been shown to be suppressed (downregulated) by the presence of elevated creatine in the blood stream. Supplementing during pregnancy may therefore, interfere with the endogenous role of AGAT in fetal development. Although provocative, this result needs to be expanded upon and corroborated in the placenta of pregnant human females.
A similar concern arose from the finding that the expression level of the creatine transporter changes dramatically during the first few weeks of life in certain animal species. For instance, in rabbit pups the level of creatine transporter expressed on neurons within the brain drops by 60% between the first 5 to 15 days of life. That is, after birth. Given the fact that serum creatine levels have been shown to influence the expression of the creatine transporter, the possibility thus exists that exogenous creatine supplementation may upset an inherent developmental program based on natural changes in serum creatine levels. Again, this phenomenon remains to be corroborated in humans.
How to best combine creatine, exercise, diet and nutritional supplements in order to optimize your anabolic hormone levels and preserve existing muscle mass is clearly explained in my creatine guide.
Still have questions about creatine? You'll probably find the answers in my ebook!
Creatine: a practical guide will teach you how to use creatine safely and effectively for greatest muscle growth. You'll learn: how to design your own personalized dosing protocol, what to eat (and what not to eat) and other methods to make the greatest muscle gains, at the lowest price. Also, find out whether expensive creatine formulations are really worth the money!
All for less than the cost of your monthly creatine!