Kirstine Suszkiewicz Krogholm

Evaluation of flavonoids and enterolactone in overnight urine as intake biomarkers of fruits, vegetables and beverages in the Inter99 cohort study using the method of triads.

Since collection of 24 h urine samples is very time consuming and difficult to obtain, epidemiological studies typically only obtain spot urine samples. The aim of the present study was to evaluate whether flavonoids and enterolactone in overnight urine could substitute flavonoids and enterolactone in 24 h urine as an alternative and more feasible biomarker of fruit, vegetable and beverage intake. A total of 191 individuals in the Inter99 cohort in Denmark completed the validation study. Concentrations of nine urinary flavonoid aglycones (quercetin, isorhamnetin, tamarixetin, kaempferol, hesperetin, naringenin, eriodictyol, phloretin and apigenin) and enterolactone were determined in overnight and 24 h urine samples, and their validity as biomarkers of fruit, vegetable and beverage intake was evaluated in relation to two independent reference methods (Inter99 FFQ data and plasma carotenoids) by using the method of triads. The intakes of fruit, juice, vegetables and tea reported in the FFQ were reflected by the flavonoid biomarker both in overnight and 24 h urine samples. Validity coefficients for the flavonoid biomarker in overnight urine ranged from 0·39 to 0·49, while the corresponding validity coefficients for the biomarker in 24 h urine ranged from 0·43 to 0·66. Although the validity coefficients were lower for overnight urine than for the 24 h urine flavonoid biomarker, they were still of acceptable magnitude. In conclusion, the results indicate that flavonoids and enterolactone in overnight urine samples may be used as a more feasible biomarker than 24 h urine for the assessment and validation of fruit, juice, vegetable and tea intakes in epidemiological studies.

A workplace feasibility study of the effect of a minimal fruit intervention on fruit intake

OBJECTIVE The main purpose of the study was to investigate the feasibility of using workplaces to increase the fruit consumption of participants by increasing fruit availability and accessibility by a minimal fruit programme. Furthermore, it was investigated whether a potential increase in fruit intake would affect vegetable, total energy and nutrient intake. DESIGN A 5-month, controlled, workplace study where workplaces were divided into an intervention group (IG) and a control group (CG). At least one piece of free fruit was available per person per day in the IG. Total fruit and dietary intake was assessed, using two 24 h dietary recalls at baseline and at endpoint. SETTING Eight Danish workplaces were enrolled in the study. Five workplaces were in the IG and three were in the CG. SUBJECTS One hundred and twenty-four (IG, n 68; CG, n 56) healthy, mainly normal-weight participants were recruited. RESULTS Mean daily fruit intake increased significantly from baseline to endpoint only in the IG by 112(se 35) g. In the IG, mean daily intake of added sugar decreased significantly by 10·7(se 4·4) g, whereas mean daily intake of dietary fibre increased significantly by 3·0(se 1·1) g. Vegetable, total energy and macronutrient intake remained unchanged through the intervention period for both groups. CONCLUSIONS The present study showed that it is feasible to increase the average fruit intake at workplaces by simply increasing fruit availability and accessibility. Increased fruit intake possibly substituted intake of foods containing added sugar. In this study population the increased fruit intake did not affect total energy intake.

Relative bioavailability of the flavonoids quercetin, hesperetin and naringenin given simultaneously through diet

The bioavailability and urinary excretion of three dietary flavonoids, quercetin, hesperetin and naringenin, were investigated. Ten healthy men were asked to consume a ‘juice mix’ containing equal amounts of the three flavonoids, and their urine and plasma samples were collected. The resulting mean plasma area under the curve (AUC)0−48h and Cmax values for quercetin and hesperetin were similar, whereas the AUC0−48h of naringenin and, thus, the relative bioavailability were higher after consumption of the same dose. The study consolidates a significantly lower urinary excretion of quercetin (1.5±1%) compared with hesperetin (14.2±9.1%) and naringenin (22.6±11.5%) and shows that this is not due to a lower bioavailability of quercetin, but rather reflects different clearance mechanisms.

Free fruit at workplace intervention increases total fruit intake: a validation study using 24 h dietary recall and urinary flavonoid excretion

Background/Objectives:To validate 24 h dietary recall of fruit intake by measuring the total 24 h excretion of 10 different flavonoids in 24 h urine during an intervention with free fruit at workplaces.Subjects/Methods:Employees at workplaces offering a free-fruit program, consisting of daily free and easy access to fresh fruit, and controls employees at workplaces with no free-fruit program were enrolled in this validation study (n=103). Dietary intake was assessed by using a 24 h dietary recall questionnaire at baseline and approximately 5 months later. Ten flavonoids, quercetin, isorhamnetin, tamarixetin, kaempferol, hesperetin, naringenin, eriodictyol, daidzein, genistein, and phloretin, were measured using HPLC–electrospray ionization–MS.Results:The 24 h urinary excretion of total flavonoids and the estimated intake of fruits were significantly correlated (r s=0.31, P<0.01). The dietary intake of citrus fruits and citrus juices was significantly correlated with total excretion of citrus specific flavonoids (r s=0.28, P<0.01), and orange was positively correlated with naringenin (r s=0.24, P<0.01) and hesperetin (r s=0.24, P<0.01). Phloretin in urine was correlated with apple intake (r s=0.22, P<0.01) and also with overall estimated intake of fruit (r s=0.22, P<0.01).Conclusions:This study shows that a 24 h dietary recall can be used as a valid estimate of the intake of fruits in agreement with an objective biomarker of fruit intake in free fruit at workplace interventions.