Bulletin

Issue: June 2005

News

Creatine myth exposed

Athletes and other sports people using the popular ‘performance-enhancing’ substance creatine – promoted and legally sold internationally as creatine monohydrate – are probably deluding themselves about its benefits.

Dr Murphy, right, and Professor Lamb.

Scientists from La Trobe University’s Muscle Cell Researwch Group in the Department of Zoology have discovered that the short-lived improvement athletes seem to achieve in muscle mass and performance after ingesting creatine is not a consequence of the substance itself, but of increased water drawn into their muscles to balance the creatine intake.

While their muscles may appear to have increased slightly in size and weight, and they sometimes do get a fractionally enhanced spurt of initial power, both effects are temporary, fi nite, and largely an illusion. The muscles are merely swollen with water, which must subsequently be excreted, and any slight boost in energy is the result of a mechanical reaction of the muscle fi bres to their ionically-changed cellular environment, and not a creatine-enhanced protein synthesis, as is commonly believed. Consequently, the muscles will defl ate and the energy effect won’t last.

Led by Research Fellow Dr Robyn Murphy, three scientists from La Trobe University Department of Zoology’s Muscle Cell Research Group (MCRG) have established that it is accumulated water - necessarily drawn in to the muscles by osmosis - that is the critical factor, and not imported creatine or increased levels of the energy-catalysing creatine phosphate. (Creatine is a colourless, crystalline substance occurring naturally in the body that is essential for the maintenance of intracellular stores of adenosine triphosphate, ATP, the primary source of energy in muscle contraction. Commercially-produced creatine is a synthetic version of it.)

Experimenting with muscle fi bres from rats, Dr Murphy and her colleagues - National Health and Medical Research Council Senior Principal Fellow Professor Graham Lamb, and Professor George Stephenson - discovered that muscle cells react to a combination of supplementary creatine and accompanying water molecules with a slightly increased sensitivity to calcium, which generates a slightly larger contraction, or impetus (force), that does not occur when the cells are exposed to creatine without water. (When exposed to creatine without the extra water, their energy- generating capacity deteriorates.)

Building on Dr Murphy’s earlier work tracking the transportation of creatine into the muscles, the experiments developed an entirely new line of inquiry into understanding the chemistry of creatine supplementation - focusing particularly on the role of osmosis.

By separating the effects of creatine with and without water, the group confi rmed that it is the water content of the creatine plus water process that causes the muscles to swell, and the dilution of energy-charged particles in the muscle cells which causes ionic changes leading to the slight increase in force. Their fi ndings add a new dimension to scientifi c thinking about what occurs when people take creatine supplements.

Many creatine enthusiasts take it believing they are topping up the body’s naturally-occurring creatine phosphates (which the muscles call on to synthesize ATP), thus augmenting their strength at critical moments with a brief, sudden shot of power to get them ‘over the line. ‘

While many sporting coaches and trainers say ‘the proof is in the pudding, the stuff works’, this new research suggests the pudding isn’t quite all the proof they think it is. ‘If people taking creatine supplements do see some kind of effect, if their muscles seem to be getting bigger, or their performance initially is a bit better, they shouldn’t be thinking it’s anything to do with energy and they can therefore fool the system and keep going longer,’ says Professor Lamb. ‘Basically, they’re swelling their muscles with water, and that’s why it works. Dr Murphy’s work beautifully explains why the small improvement in performance occurs, better than you could ever explain it for any energy reasons. If it’s people’s view that it’s something they’re eating, but all they’ve done is swollen their muscles with water, they mightn’t be nearly so impressed. ‘

Dr Murphy said people often thought that by ingesting creatine their bodies would make more protein, but recent work had shown there is no increase in muscle protein as a consequence of creatine supplements. Any increase in muscle size could be fully accounted for by the water.

Professor Lamb said he had always been concerned with the rationale for people taking creatine: that they were eating the end product of a reaction hoping to get the energy part of it, when there was no evidence for this in any of the literature.

‘We’ve only looked at one small part of the whole process of how muscles work, and shown what looks like the full explanation of why you can get a small increment in performance, and it has nothing to do with energy.

‘There’s more for us to do to try to understand the energy consequences, but if you take the results at face value you could also say the creatine is actually deleterious by itself, that is, if you didn’t have the muscle cells swelling with water you would actually make the energy balance a little bit worse. What’s important about this work is that it may stop people incorrectly extrapolating increases in performance. It provides an explanation for the benefits seen before there is any change in the energy state of the cells. ‘

The MCRG’s findings are likely to generate significant interest in gymnasiums and sporting clubs where creatine attracts its greatest devotees, particularly in the United States where it is reportedly the most commonly used performance enhancing substance on the market.

It is sold commercially in a semi-soluble powder form popular with body-builders, weight-lifters, gymnasts, sprinters, footballers, tennis players, lap swimmers and other athletes seeking short, controlled power surges. Because it is known to be ineffective over extended periods it holds no appeal for long-distance or endurance athletes.