The randomised, crossover study, 'Bananas and Exercise Metabolism', recruited 14 trained cyclists, male and aged 18-45, who ate a moderate carbohydrate diet and did not use vitamin, mineral, herbal and other relevant medications.
Niemen et al. found that acute ingestion of bananas (BAN) or 6% carbohydrate drink Gatorade (CHO) – all cyclists completed the study consuming both the beverage and fruit separately in a crossover – supported 75km of time trialing and underlying metabolic processes to a similar degree.
Introducing their study, Niemen et al. noted that heavy exertion induced transient inflammation, oxidative stress and immune system perturbations, and that endurance athletes saw bananas as a good source of carbohydrates, nutrients and antioxidants.
“[Bananas] may provide good nutrition support during prolonged and intensive exercise, but published data from studies with human athletes are lacking,” the authors wrote.
No difference in performance measures
Cyclists ingested BAN or CHO at a rate of 0.2g/kg carbohydrate every 15 minutes – after one 0.4g/kg carbohydrate dose prior to exercise – and were able to complete the time trials with no difference in performance measures, the study found.
Niemen et al. wrote: “Changes in blood glucose, inflammation, oxidative stress, and innate immune measures were also comparable between BAN and CHO 75km cycling trials, and similar to what we have previously reported for carbohydrate-fed athletes.”
Serum metabolite shifts (metabolites are intermediates and products of metabolism) following BAN and CHO time trials were extensive, and indicated increased liver glutathione production and fuel substrate utilisation, including glycolysis, lipolysis and amino acid catabolism, the authors wrote.
Total plasma antioxidant power was higher during BAN compared to CHO, but the authors said this did not translate to diminished oxidative stress. Higher serum levels of free dopamine in BAN also had no demonstrable cardiovascular effects.
Can supplements beat banana bloat?
Future studies with banana peel-based supplements would reveal if high oral dopamine intake was advantageous for endurance athletes using similar performance and physiological outcomes, the authors predicted.
“In general, ingestion of bananas before and during prolonged and intensive exercise is an effective strategy, both in terms of fuel substrate utilisation and cost, for supporting performance,” they wrote.
Niemen et al. added: “Despite dissimilar carbohydrate profiles, 75km cycling performance and metabolic outcomes were similar when comparing CHO and BAN under conditions where total carbohydrate intake was matched.
Nonetheless, bulk banana consumption (6-7 within a two to three hour period) did present some problems.
“Subjects felt somewhat more full and bloated after cycling 75km with BAN compared to CHO, and this was probably related to the nearly 15g of dietary fibre consumed,” Niemen et al. wrote.
Title: ‘Bananas and Exercise Metabolism’
Authors: D.C. Niemen, N.D Gillitt, D.A. Henson, W.Sha, R.A Shanely, A.M Knab
Source: Plos One, published online May 17 2012 doi:10.1371/journal.pone.0037479