University of South Carolina study published earlier this year found that when 12 college-age volunteers increased quercetin intake over the course of a week while being tested for exercise endurance on stationary bikes, they not only improved their oxygen uptake by 4%, they were able to ride 13% longer before becoming fatigued (106 minutes compared to 93 minutes for the placebo). Researchers say the supplemental quercetin helps marshal the body’s mitochondria — the cellular dynamos that harness the energy released from food. Top quercetin sources include: tea, capers, apples, red onions and berries.

Quercetin is also under study for possible anti-Alzheimer’s benefits as well as the mitigation of prostatitis pain. While most quercetin studies thus far have used supplements, eating a wide variety of quercetin-rich sources will also provide the synergistic benefits of whole foods.

Bonus: You can also boost stamina with beets, which contain compounds that help improve aerobic efficiency by nearly 20%.

 Published April 1, 2010