Flavonoids are suggested to reduce disease risk. Since dietary habits are acquired during early life, describing age and time trends of flavonoid intake and major food sources are important for monitoring and disease prevention in later life. We aimed to describe total flavonoid intake and food sources and to investigate age and time trends of flavonoid intake in 3–18-year-olds, from the Dortmund Nutritional and Anthropometric Longitudinally Designed study from 1985 to 2016. Intake was assessed annually using 3-d weighed food records (WFR). Flavonoid values were assigned using the United States Department of Agriculture database. Foods contributing to intake were determined. Age and time trends in total flavonoid and isoflavone density were analysed by sex with PROC MIXED. In total, 1312 children completed 10 758 WFR. Across all ages, daily mean total flavonoid density was lower in boys compared with girls (134 v. 146 mg/4184 kJ) and no difference in median isoflavone density (0·04 mg/4184 kJ per d) was found. The top five foods contributing to total flavonoid intake were apple with peel (15·0/17·1 %), strawberries (5·9/6·1 %), chocolate spread (3·9/3·5 %), orange juice (3·5/3·4 %) and pasta (3·5/3·4 %) for boys and girls, respectively. Overall, in boys, total flavonoid density decreased over the course of age and time. In girls, there was no association with age or time. In both sexes, isoflavone density followed a U-shaped age trend with no change over time. From a public health perspective, the overall observed downwards trend of flavonoid intake in boys deserves attention. Future initiatives should be tailored at maintaining a high flavonoid density as children age, specifically among boys.

Fortifying complementary foods with lipid-based nutrient supplements (LNS) may improve energy and nutrient intakes of infants at risk for undernutrition. We aimed to determine the relative validity of an interactive 24-h recall (i-24-HR) for assessing the impact of an LNS intervention on dietary intakes of energy and nutrients among rural Malawian 9–10-month-old infants (n 132) participating in the International Lipid‐Based Nutrient Supplements Dose (iLiNS-DOSE) trial. Dietary data were collected for the same day via i-24-HR and weighed food records. Inter-method agreements were estimated overall and by intervention group, using Bland–Altman plots and paired t tests; measurement error models (differential error); and percentage of food omissions and intrusions were estimated. Overall, inter-method differences in mean intakes of energy and most nutrients were not significant. When stratified by group, recalled energy intakes were under-estimated (−368 kJ; P=0·01) in the control but not in the intervention group (−42 kJ; P=0·6). This differential reporting error was related to an over-estimation of recalled LNS (8·1 v. 4·5 g; P<0·001) in the intervention group, compensating for an under-estimation of energy and nutrient intakes from complementary foods. Sources of measurement error in the i-24-HR were under-estimations of starchy staples, meat/fish/eggs and legumes/nuts/seeds (overall percentage agreement between 38 and 89 %; P<0·028); and over-estimations of added sugar, soups/broths and LNS (overall percentage agreement between 138 and 149 %; P<0·001). Common (>30 % eating occasions) omissions were milk/fish/eggs, starchy roots/vegetables and sweetened snacks. Common intrusions were milk/yogurt. Starchy staples and LNS were recalled when consumed (>85 %) (i.e. matched). These results emphasise the importance of considering differential error when interpreting dietary results in LNS trials.

The Dietary Questionnaire for Epidemiological Studies version 2 (DQES v2) FFQ has not been validated in adults with diabetes. The aim was to determine the agreement between the DQES v2 FFQ and a 3-d weighed food record (WFR) and 24-h urinalysis in adults with type 1 and type 2 diabetes. The DQES v2 FFQ and a 3-d WFR were completed on one occasion for measurement of food and nutrient intake. A 24-h urine sample was provided for measurement of Na and K excretion. Participants were sixty-seven adults with type 1 and type 2 diabetes recruited from the community. Nutrient intake reported in the FFQ was within 20 % of the corresponding intake level reported in the WFR for the majority of nutrients. However, the 95 % limits of agreement showed large variation at an individual level between the two methods. There was a weak to moderate correlation between nutrient intake measured using the two methods and a moderate to high correlation for food intake. Quintile analysis showed that for the majority of foods and nutrients >60 % of participants were ranked within 1 quintile of the WFR ranking. The weighted κ values showed slight to moderate agreement between the two methods. Na intake was under-estimated in the FFQ by 25 % and K intake was over-estimated by 5 % compared with the 24-h urinalysis. In adults with type 1 and type 2 diabetes, it is appropriate to use the DQES v2 FFQ to measure food and nutrient intake at a group level.