Using an FFQ to assess intakes of dietary flavonols and flavones among female adolescents in the Suihua area of northern China

Objective: The present study aimed to (i) evaluate the reproducibility and validity of a designed FFQ, (ii) apply the FFQ for estimating the dietary intakes of four flavonols and two flavones in female adolescents and (iii) explain their major dietary sources. Design: The reproducibility between the first and second FFQ administrations (1 year interval) was estimated using the intra-class correlation coefficient. The validity of the first FFQ relative to the average of four three-day 24 h dietary recalls (24-HR) from four seasons was assessed using the Spearman correlation coefficient. Using a flavonoid content database, the individual flavonol and flavone intakes were calculated and the major food sources were estimated. Setting: Middle school in Suihua area of Heilongjiang Province, northern China. Subjects: Female adolescents (n 887) aged 12-18 years. Results: Better reproducibility and validity were obtained in the present study. The flavonol and flavone intakes were 16.29 and 4.31 mg/d, respectively. Quercetin and kaempferol were the major contributors (26.8 % and 23.7 %, respectively) to the total intake of flavonols and flavones. The main food sources of flavonols and flavones were apples (14.1 %), followed by potatoes (7.5 %), lettuce (7.3 %) and oranges (7.3 %). Conclusions: The dietary flavonol and flavone intakes among female adolescents in northern China were similar to those reported in several countries, but significant differences were observed in the food sources ascribed to the geographical location and dietary characteristics.