Intake and major sources of dietary flavonoid in Korean adults: Korean National Health and Nutrition Examination Survey 2010-2012

With an effort to investigate possible relationship between flavonoids and health, an accurate estimation of flavonoid intake is valuable. We estimated dietary flavonoid intake and identified the major food sources. Subjects were healthy adults aged ≥19 y (n=11,474) who completed the 24-h dietary recall of the Korean National Health and Nutritional Examination Survey (2010-2012). The US Department of Agriculture and newly estimated or published values for typical Korean foods were combined into a Korean-targeted flavonoid database. The mean intake of total flavonoid was 107±1.47 mg/d, with a higher intake in women than in men after energy-adjustment. Quercetin, cyanidin, genistein, daidzein, epigallocatechin 3-gallate, epicatechin, hesperetin, and luteolin were identified as major flavonoid compounds. Across the age range studied, flavonols and flavones showed a reversed U-shape curve; flavan-3-ol and flavanones showed a decreasing pattern; and anthocyanidins and isoflavones showed an increasing pattern. Forty-five food items were identified as contributing >2% of at least one flavonoid compound's intake. Kimchi was the major food source of total flavonoids, followed by green tea, persimmons, and soybeans. Single food items accounting for more than 50% of the intake of a specific flavonoid included persimmons (cyanidin), green tea (epigallocatechin, epicatechin-3-gallate, and epigallocatechin 3-gallate), black tea (thearubigin), tangerines (hesperetin and naringenin), and onions (isorhamnetin). This study provides information on Korean flavonoid intake to enable international comparisons, along with insight into how the sources and intake of various flavonoids vary according to age and gender. This work should facilitate future investigations of the association between flavonoid intake and health.