Cranberries are rich in polyphenols, powerful antioxidants
Cranberries have the highest polyphenol and antioxidant capacity among fruits and vegetables and may protect against exercise-induced free radical production, consequently improving performance. A new study was designed to investigate the effect of polyphenol-rich cranberry extract on time-trial performance and lactate response following exercise.
“When it comes to elite athletes, any advantage can make the difference between finishing fifth or on the podium,” says Andreas Bergdahl, an associate professor and the paper’s senior author.
Time trials to test the impact of cranberries on performance
The researchers recruited 14 high-level runners who spent at least 5 hours per week on endurance training. The experiment consisted of 3 separate tests where the participants were asked to perform two different time trials, 1,500 m and 400 m long.
- Time trials to establish a baseline
- Time trials after a single large dose of cranberry extract (0,7 g/kg of body mass)
- Time trials after 28 days of daily cranberry extract supplementation (0,3 g/kg of body mass)
“We selected these distances to test the effects the cranberry extract had on different energy systems. The 400-metre one is shorter and of higher intensity and involves the anaerobic system. The 1,500-metre one uses the aerobic system but is shorter than what the athletes usually run. Since they do not train to run that distance, we were able to isolate training effects as a variable,” said Francis Parenteau, PhD, the paper’s lead author.
The researchers measured participants’ running times as well as post-exercise blood lactate, a marker for potential muscle fatigue and lack of oxygen. The participants also wore a device to measure muscle oxygenation levels before, during, and after their runs.
Cranberry extract improved aerobic performance
Following data analysis, the researchers found that the acute large dose had no effect on performance. However, the 28 days of cranberry extract supplementation showed more promising results. Here are the main observations:
- Increased speed by 1,5% in the 1,500 m time trial but not in the 400 m.
- Improved aerobic performance during the 1,500 m time trial, faster oxygenation by the muscle and slower deoxygenation.
- Reduced lactate buildup following the 400 m but not the 1,500 m compared to baseline.
“The beauty of this is that it is all natural. It is an ergogenic aid, meaning that it is performance-enhancing but it is not an anabolic steroid. Athletes can get this important boost in their performance just by consuming more cranberries,” said Bergdahl.
