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19.02.2010


How to combine creatine and caffeine – and how not to

It’s better not to use creatine and caffeine [structural formulae shown below] together. This was the message in a human study published by sports scientists in Belgium 15 years ago. And a recent Japanese test-tube study shows why.

Creatine

Caffeine

Imagine this: you give a 90 kg bodybuilder 45 g creatine for 6 days in a row. The effect is a 5 percent increase in the amount of phosphocreatine in his muscles, making him 10-20 percent stronger. If you give the same bodybuilder a daily 450 mg caffeine in addition, then there’s no increase in muscle strength. Belgian researchers published these results in 1996. [J Appl Physiol. 1996 Feb; 80(2): 452-7.]

It would appear that creatine and caffeine get in each other’s way. But 6 years after the Belgian research was published, the results of a study done at the University in Luton were made known. These results seemed to suggest that creatine and caffeine were not affecting each other. [Med Sci Sports Exerc. 2002 Nov; 34(11): 1785-92.]

If the imaginary bodybuilder from the Belgian study had taken part in the British study he would have taken a daily 27 g creatine for 6 days. After this period the researchers would have tested his stamina on a treadmill, seeing how long he could stay running. On one occasion he took 450 mg caffeine an hour before running, on the other occasion he took a placebo.

It was already known that creatine supplements extend the amount of time someone can run, and that caffeine has the same effect. But does a single time dose of caffeine improve performance in athletes who’ve already charged their muscles with creatine? That’s the question the Brits wanted an answer to. And they got a ‘yes’.




The figure above shows the effect of caffeine on the test subjects’ running time. In some of the subjects caffeine reduced the running time, but in most a single dose did have added value, on top of the creatine.

The test subjects consumed no products containing caffeine during the 6 days of creatine loading.

So athletes can benefit from a one-time high dose of caffeine if they use creatine [British study reasoning], but not if they consume high doses of caffeine on a regular basis [Belgian study reasoning]. And now a Japanese study published two months ago in Metabolism throws light on why this is so. [Metabolism. 2009 Nov; 58(11): 1609-17.]

The Japanese wanted to know whether caffeine imitates the positive effects of physical exercise on muscle cells – and their study provided an affirmative answer. They exposed cells from rats’ soleus calf muscle to caffeine in a test tube.

Physical exercise reduces the amount of fuel in the muscle cells. As a result the enzyme AMPK becomes more active in these cells – and this is an enzyme that tells muscle cells that they should be doing the kind of things that doctors say are healthy. The muscle cells start burning fat and become more sensitive to insulin – that kind of thing. That’s why researchers everywhere are working on pills that activate AMPK. Caffeine is also a bit of an AMPK booster, the Japanese discovered. The figure below shows the activating effect of caffeine on AMPK.



In this process, however, the amount of creatine in the muscle cells decreases, the Japanese discovered. And this happens within minutes.



Of course, the concentrations the Japanese used are much higher than the concentrations found in the human body, but the message is clear. Caffeine messes up the muscle cell’s creatine metabolism.

If you take creatine, high daily doses of caffeine will cancel out its effect. But the effect of caffeine is apparently not so strong that it’s no use at all to creatine takers. A one-time high dose of caffeine does have an effect. So during a course of creatine you could occasionally use caffeine as a training booster. Taking caffeine daily is not a good idea though.

Source:
J Appl Physiol. 1996 Feb; 80(2): 452-7.

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