This flu season, try quercetin

The August 1, 2008 issue of the American Journal of Physiology-Regulatory, Integrative and Comparative Physiology reported the details of a study conducted by researchers at the University of South Carolina and Clemson University which found that quercetin, a compound that occurs in many fruits and vegetables, helped protect against influenza in mice exposed to the virus.

In the current study, conducted by J. Mark Davis of the University of South Carolina’s Arnold School of Public Health and colleagues, one group of mice was given quercetin for seven days while the remainder received no quercetin. Half of the mice in each group were exercised to fatigue on the last three days of the treatment period.

One half hour following the final exercise session, the animals were inoculated with an influenza A strain, and were monitored for signs of illness for 21 days. Mice that experienced exercise-related stress demonstrated a greater susceptibility to influenza. Ninety-one percent of these mice developed signs of the flu, compared with 63 percent of nonexercising animals. Mice that exercised to fatigue also exhibited signs of the flu earlier than other animals that developed influenza.

Among those that received quercetin, however, the same rate of influenza occurred as in mice that did not exercise, demonstrating that the compound cancelled the temporary stress-related depression of immune function caused by intense exercise. Mice that did not engage in intense exercise also experienced a protective benefit from quercetin. Continue Reading