The volunteers also showed less-stressed metabolite profiles if they had had carbohydrates during their rides, whether those calories had come from a bottle or a banana.
But there were differences in the activity of some genes. In particular, the scientists found that the riders’ blood cells produced less of a genetic precursor of an enzyme known as COX-2 if they had eaten bananas during their workout. This effect was not seen if they had drunk the sports drink or only water.
The COX-2 enzyme prompts the production of prostaglandins, which, in turn, intensify inflammation. Less of the genetic precursor in cells after a workout should mean less COX-2 and reduced inflammation, says David Nieman, the director of the human performance lab at Appalachian State University and the study’s lead author.
He points out that anti-inflammatory drugs such as ibuprofen work by inhibiting COX-2, but, until now, researchers had not considered that bananas might perform comparably.
How the fruit manages to affect the cells’ gene expression after exercise is still not known, however, he says.
He and his colleagues also do not know whether half of a standard banana every 30 minutes is the ideal amount of the fruit during exertion. Although it provided as many carbohydrates as in a cup of the sports drink, it also resulted in “quite a bit of bloating,” he says, which might dampen some athletes’ enthusiasm.
He and his colleagues plan to explore those issues in future studies and also look into the effects of other fruits. “Dates have even more sugar than bananas,” Dr. Nieman says.
In the meantime, he says, for exercisers who might prefer a natural, inexpensive and neatly packaged alternative to sports drinks, “bananas look pretty good.”