By David C. Nieman, DrPH, Facsm, Director, Human Performance Lab,
North Carolina Research Campus; Professor, Appalachian State University (Boone, NC)
A newly published study in the prestigious journal, PLoS ONE [a peer-reviewed, open-access online resource reporting scientific studies from all disciplines], confirms that bananas are an effective and healthy energy source for athletes. My research group from the Kannapolis-based Appalachian State University Human Performance Laboratory at the North Carolina Research Campus used a new technology called metabolomics and showed that bananas provided fuel to the working muscles just as well as a popular sports drink. Metabolomics using mass spectrometry-based techniques to measure the shift in hundreds of metabolites or small molecules in the body that occur in response to nutrition and exercise interventions.
Bananas are common at road race events because they are a cost-effective energy source for athletes, and contain high amounts of the sweat electrolyte potassium. A direct comparison of bananas with sports drinks as a fuel source during exercise had not yet been investigated. In the PLoS ONE publication, we theorized that bananas offered several unique advantages for athletes. One medium banana contains about 27 grams of carbohydrate (half as sugars), 105 calories and is a good source of potassium and vitamin B6. Potassium is an important electrolyte during exercise, and the sugars in bananas are a mixture of glucose, fructose, and sucrose, similar to what is found in sports drinks. The glycemic index of bananas is 51 (low-to-medium rating), meaning the sugars in a banana are not released too fast or too slow, an important potential benefit for the exercising athlete. The antioxidant value of bananas is higher than most athletes perceive and is equal to levels found in kiwi fruit and orange juice. Thus, as hypothesized, bananas appear to be a unique mixture of carbohydrates, nutrients, and antioxidants that may provide good nutrition support during prolonged and intensive exercise.
Trained cyclists from the Charlotte, NC, metropolitan area were recruited and agreed to engage in two 75-kilometer cycling race trials in the Human Performance Lab. In randomized order, cyclists either ingested specified quantities of a sports drink or bananas. Results from this study support the perception of athletes that bananas are a healthy alternative to sports drinks. We had trained cyclists race 75 kilometers on their bicycles on CompuTrainers (RacerMate, Seattle, WA) in the lab. In randomized order, subjects exercised once while drinking about one cup of sports beverage every 15 minutes or a second time while consuming one-half banana every 15 minutes with water. An in-depth metabolomics analysis of blood samples obtained from the athletes showed that bananas provided all of the fuel needed for intense exercise, and equaled the rate of the sports drink.
The typical increase in inflammation and oxidative stress following intense exercise was attenuated to a similar degree by bananas and the sports drink, significantly below levels experienced when just water was consumed. Bananas also provided added nutritional benefits including a boost in antioxidant capacity, and significant potassium and vitamin B6.
We concluded that ingestion of bananas before and during prolonged and intensive exercise is an effective strategy, both in terms of fuel substrate utilization and cost, for supporting performance. Most athletes are health-conscious, and try to consume nutrient-dense diets to support their heavy training. The data from this study support the growing trend of athletes to use fresh and dried fruit as substitutes for sugar-laden sports drinks. We are currently conducting similar studies using watermelon slurry, a blended fruit and vegetable juice, and selected flavonoids from blueberries and green tea to determine their efficacy in helping the athlete meet the physiologic demands of prolonged and intensive exercise.