A banana might reasonably replace sports drinks for those of us who rely on carbohydrates to fuel exercise and speed recovery, according to a new study comparing the cellular effects of carbohydrates consumed during sports.
It found that a banana, with its all-natural package, provides comparable or greater anti-inflammatory and other benefits for athletes than sports drinks.
But there can be a downside, and it involves bloating.
For decades, athletes and their advisers have believed, and studies have confirmed, that eating or drinking carbohydrates during prolonged exertion can enable someone to continue for longer or at higher intensities and recover more quickly afterward than if he did not eat during the workout.
The carbohydrates rapidly fuel muscles, lessening some of the physiological stress of working out and prompting less inflammation afterward. The most digestible and portable form of carbohydrate is sugar, whether glucose, fructose or sucrose, and for athletes, this sugar is conveniently provided by sports drinks.
But sports drinks are not a substance found in the natural world. They are manufactured and can contain flavorings and chemicals that some wish to avoid.
Researchers at the North Carolina Research Campus of Appalachian State University in Kannapolis, N.C., began to wonder about fruits as a healthier alternative to sports drinks during exercise.
Most fruits, including bananas, are sugary and high in fructose; fructose, after all, means fruit sugar. But they also contain other natural substances that might have an impact on sport performance and recovery, the researchers speculated.
In a preliminary experiment, published in 2012, the scientists found that cyclists performed better during a strenuous bike ride if they had either a banana or a sports drink compared to only water. They also developed lower levels of inflammation in their bodies afterward.
But that study had left many questions unanswered.
So for the new experiment, which was published in March in PLOS One, the researchers decided to use more sophisticated techniques to track molecular changes inside cyclists' bodies.
(Dole Foods, which sells bananas, partly funded both studies. According to a statement in the study, the company did not have any involvement in "the study design, data collection and analysis, decision to publish or preparation of the manuscript.")
The researchers asked 20 competitive cyclists, male and female, to complete a grueling 47-mile bike ride on several occasions at the campus performance lab. During one ride, they drank only water. In the others, they had water but also 8 ounces of a sports drink or about half a banana every 30 minutes.
The scientists drew blood before the workout, immediately after and at several additional points, stretching out to 45 hours later.
They checked the blood for markers of inflammation and levels of hundreds of molecules, known as metabolites, that can change during and after exertion and signify how much stress the body feels.
They also isolated blood cells to look at the activity of certain genes involved in inflammation.
As they had expected, the scientists found that swallowing only water resulted in relatively high levels of inflammatory markers in the riders' blood. These markers were much lower if the cyclists had consumed fruit or the sports drink.
The volunteers also showed less-stressed metabolite profiles if they had consumed 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, said David Nieman, the director of the human performance lab at Appalachian State University and the study's lead author.
ActiveStyle on 04/23/2018