Researchers from the Foro Italico University of Rome found evidence that regular intake of quercetin, a natural flavonoid found abundantly in vegetables and fruits, can prevent damage to red blood cells (erythrocytes) caused by oxidants. This finding was published recently in Nutrition Research following a clinical trial.
Quercetin is known to modulate the signaling pathways and gene expression involved in animal and human cells, thus exhibiting antioxidant, anti-inflammatory, and anticancer properties.
Little is known about its effect on the redox status of humans, particularly in combination with strenuous exercise.
The researchers wanted to find out if regular consumption of quercetin supplements would be beneficial to the redox homeostasis of healthy persons doing eccentric exercise.
Fourteen individuals were recruited for a two-week controlled, randomized, crossover, intervention trial. Each one took one gram of quercetin or placebo each day.
Blood samples were taken before, after two weeks of quercetin consumption, and after a bout of eccentric exercise.
Quercetin significantly reduced erythrocytes' lipid peroxidation levels and their susceptibility to hemolysis induced by the free radical generator AAPH, while no differences in antioxidant enzyme activities and glutathione homeostasis were found between the test and control groups.
After a single bout of eccentric exercise, quercetin supplementation improved redox status as shown by the reduced/oxidized glutathione ratio and reduced thiobarbituric acid reactive substances (TBARs) levels both in erythrocytes and plasma.
Overall, the results suggest that regular consumption of quercetin supplements protects red blood cells (erythrocytes) from damage by oxidants prior to and after strenuous eccentric exercise.
Duranti G, Ceci R, Patrizio F, Sgro P, Luigi LD, Sabatini S, Felici F, Bazzucchi I. CHRONIC CONSUMPTION OF QUERCETIN REDUCES ERYTHROCYTES OXIDATIVE DAMAGE: EVALUATION AT RESTING AND AFTER ECCENTRIC EXERCISE IN HUMANS. Nutrition Research. February 2018;50. DOI: 10.1016/j.nutres.2017.12.002