Urinary excretion of kaempferol from common beans (Phaseolus vulgaris L.) in humans

The aim of this study was to assess kaempferol bioavailability in healthy humans, after bean ( Phaseolus vulgaris L.) consumption through the monitoring of the excretion in relation to intake. In seven healthy subjects receiving kaempferol from cooked bean, maximum excretion of hydrolysed flavonol was obtained after 2-8 h. Intersexual variations in urinary excretion were found to be 6.10 +/- 5.50% and 5.40 +/- 5.40% of the kaempferol dose for male and female subjects, respectively. Although a 6.72-fold inter-individual variation between the highest and lowest excretion concentrations was found, all individuals exhibited similar excretion profiles. Moreover, a direct correlation between the percentage of kaempferol excreted and the body mass index of volunteers was observed with a correlation index equal to 0.80. All except two individuals exhibited a first peak of kaempferol excretion 2 h after ingestion. The study reveals information about inter-individual excretion capacity after kaempferol intake and that kaempferol can be used as a biomarker for flavonol consumption.