Study leader Dr. Johannes Scherr of Technische Universitaet Muenchen at Klinikum and colleagues examined 277 test subjects three weeks before and two weeks after the 2009 Munich Marathon.
Non-alcoholic Erdinger wheat beer was selected as the test beverage because of its rich and varied polyphenol content and its popularity with marathoners and triathletes.
The "active" group drank up to 1.5 liters -- more than six glasses of beer -- of the test beverage per day, while a second group consumed an equal amount of an otherwise indistinguishable placebo beverage that contained no polyphenols and was produced specifically for the study, Scherr says.
The study found after running a marathon race, athletes experience intensified inflammatory reactions, the immune system is thrown off balance and runners are much more likely to suffer from upper respiratory infections.
Non-alcoholic wheat beer containing polyphenols had a positive, health-promoting effect on the human body: Inflammation parameters in the blood were significantly reduced and there was a lower frequency of infection with milder symptoms, the study said.
Scherr presented the findings to the 5,000 scientists, physicians and trainers attending the conference of the American College of Sports in Denver. The findings are also scheduled to be published in January in the journal of Medicine & Science in Sports & Exercise.