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.

The potential association between fruit intake and body weight--a review.

Both national and international bodies recommend an increased intake of fruits and vegetables in order to decrease the risk of overweight and obesity. However, there is a rationale to investigate the separate role of fruits. The aim of this paper was to systematically review and analyse published human intervention, prospective observational and cross-sectional studies on fruit intake and body weight in adults. We identified three intervention, eight prospective observational and five cross-sectional studies that explored this relationship. Two of the intervention studies showed that fruit intake reduced body weight, five of the prospective observational studies showed that fruit consumption reduced the risk of developing overweight and obesity, and four of the cross-sectional studies found an inverse association between fruit intake and body weight. Important methodological differences and limitations in the studies make it difficult to compare results. However, the majority of the evidence points towards a possible inverse association between fruit intake and overweight. Future intervention and prospective observational studies examining the direct and independent role of fruit in body-weight management in free-living individuals are needed. Moreover, important determinants such as energy density, energy content, fruit and vegetable consumption, physical form of fruit and preparation methods need to be included in future studies.