The sports supplement market is big business. And it is no wonder that athletes gravitate to the pills, powders and potions on the market for the promises they make of enhancing training and race day performance and allowing them to get the jump on their competitors. The reality is that most of these supplements have little evidence for a benefit. It is not all negative news though as there is a small group of supplements that are backed by science and which can play a performance-enhancing role in some athletes. In this series on sports supplements, I will profile this group of supplements and for this podcast, the spotlight is on creatine.
Interest in the use of creatine supplements to enhance performance during intense activity has grown dramatically in the last few years. Creatine is a naturally occurring compound that is found in muscle where it exists in the form of the compound creatine phosphate. Creatine aids rapid ATP resynthesis (ATP is the universal energy currency in the body) during short-term, maximal exercise of an intermittent nature such as sprints or power weight training. So, think of creatine as like a short-term anaerobic power source that the body can call upon when its energy demands are at a peak. Theoretically, the more creatine phosphate that is in muscles, the higher the intensity at which an athlete can train. High-intensity training stimulates the muscles to grow and adapt, which, in turn, improves performance.
Animal foods such as meat and fish are good dietary sources of creatine, but our body can naturally produce it as well. And of course, supplementing with creatine can boost muscle stores as well.
Creatine has a clear role to play in power sports like weightlifting and sprinting. These are examples of short-term, repetitive, high-intensity activities. Creatine has been linked to improving performance by increasing muscle strength and size, cell hydration and glycogen loading capacity.
So, what does the evidence say about creatine and sports performance? There have been well over 200 studies, reviews and meta-analyses done so this is one supplement that has been well researched and is backed by real science, not bro science. In fact, creatine was one of the few supplements to get the tick for having good evidence behind it in the 2018 IOC Consensus Statement on dietary supplements for use by high-performance athletes and I’ll link to this document in the show notes https://bjsm.bmj.com/content/52/7/439
Studies show the greatest benefits of creatine are in recovery from high-intensity bouts of exercise with short rest intervals. So, what that means is that it may not make a person run a quicker 100m, but they’ll be able to run faster sprint times if they’re doing it repeatedly such as in intermittent activity sports like football where they may be high-intensity bursts of activity for less than 30 seconds followed by periods of relative rest.
Creatine also has a benefit in resistance weight training with adaptations seen including lean mass gains and improvements in muscular strength and power. Benefits have been reported in men and women, although most studies have been conducted on men with some studies suggesting that women may not see as much of a strength gain or growth in muscle mass during training in response to creatine supplementation.
There is also some evidence for a benefit of creatine supplementation in enhanced endurance performance which results from increased or improved protein synthesis, glycogen storage and thermoregulation.
There are many different forms of creatine available on the market, but creatine monohydrate is the cheapest and most effective form. Another option is micronised creatine monohydrate, which dissolves in water more easily and can be more practical.
A typical creatine loading protocol is 20 g/d, divided into 4 doses across the day and then doing that for 5 to 7 days in a row. After loading, a maintenance dose of a single 3-5 grams per day can be used. Creatine is usually taken together with some carbohydrate to increase insulin release, as that insulin will increase creatine uptake into muscle. Creatine loading has been shown to increase muscle creatine content by around 20% and this is what explains the sports performance benefit.
One known downside of creatine use is weight gain of around 1 to 2 kg. All that extra creatine that is being stored drags additional water with it into the cell. So, for athletes in weight-sensitive sports such as endurance athletes or in events where body mass must be moved against gravity such as high jump or pole vault, or where athletes must achieve a specific body mass target such as lightweight rowing then the performance gain must be balanced against the weight gain.
On the question of safety, creatine is considered safe for healthy adults. Concerns in the past have been raised about:
Muscle cramps due to ↑ muscle water contentHeadaches due to ↑ water storage in the brainMuscle tears/injuries due to increased trainingInsulin resistance/diabetesCarcinogenRenal problemsBut as the research field has grown, there is little evidence to support a greater risk of any of these concerns. Things like cramping, GI problems and muscle injuries occur in both creatine and non-creatine users with little difference in the rate of occurrence. Concerns about insulin resistance and cancer have been largely dismissed. The only issue of note is that for athletes with pre-existing kidney problems, the extra protein load from creatine could place additional stress on the kidneys, but this is not to do with creatine per se, but just the presence of additional protein in the diet from supplementation.
If creatine is taken without enough water, stomach cramping can occur. Diarrhoea and nausea can occur when too much creatine is taken at once, in which case doses should be spread throughout the day and taken with meals.
So, who might benefit from creatine supplementation? Sportspeople undertaking resistance training programs to increase lean muscle mass are one group. Also, sportspeople participating in sports with repeated brief, high-intensity efforts with short recovery periods (e.g. throwers, sprinters). Sportspeople participating in sports with intermittent work patterns (e.g. team sports, racquet sports).
Just as a side-detour from the benefits of creatine on sports performance, there is a growing research base looking at creatine in other contexts. There is some interest in using creatine to improve cognitive performance with a reduction in mental fatigue seen in situations such as demanding mental activity, sleep deprivation, and traumatic brain injury.
Several studies have investigated the short and long-term therapeutic benefit of creatine supplementation in children and adults with various neuromuscular diseases like muscular dystrophies, Huntington’s disease and Parkinson’s disease. These studies have provided some evidence that creatine supplementation may improve exercise capacity and clinical outcomes in these patient populations.
One very novel direction of research to do with creatine supplementation is how it may benefit people with impaired glucose tolerance such as that seen in type 2 diabetes. Creatine supplementation together with muscle contraction from exercise can stimulate the mechanisms that muscle cells use to take up glucose. This could offer a therapeutic benefit in improving glucose control in people with diabetes.
Creatine is one of the few nutritional supplements for which research has consistently shown a sports performance benefit. The use of all supplements and sports foods by athletes though involves a balance between the potential benefits set against potential risks such as health side-effects, anti-doping rule violations from contamination, and redirection of resources from real performance-enhancing factors. So, take this into account when considering taking any sports supplement. And seek out personalised advice from a sports dietitian. You can connect with an Accredited Sports Dietitian as well as access a great range of resources through the website of Sports Dietitians Australian at www.sportsdietitians.com.au
So that’s it for today’s show. You can find the show notes either in the app you’re listening to this podcast on if it supports it, or else head over to my webpage www.thinkingnutrition.com.au and click on the podcast section to find this episode to read the show notes.
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I’m Tim Crowe and you’ve been listening to Thinking Nutrition.