Including fruit juice and smoothies within 5-a-day fruit and vegetable intake recommendations: A randomised controlled trial investigating impact on levels of intake, mood, and markers of health

Abstract

Consuming fruit juice/smoothies could help overcome barriers to fruit and vegetable (F&V) intake. However, their contribution towards F&V intake within a healthy diet is contentious. We investigated how F&V intake is affected by UK 5-a-day advice, with and without one portion/day of fruit juice/smoothies and explored how these interventions impacted markers of health. Healthy individuals (n=42) with low F&V intake (≤2 servings/day) completed a four-week, parallel-group randomised controlled trial (ClinicalTrials.gov ID: NCT06628401). Participants were randomised to 1) control, 2) whole F&V (FV), or 3) whole F&V plus fruit juice/smoothies (FV+FJ). All groups received weekly financial support (to remove financial barriers to F&V purchase in the intervention groups). FV and FV+FJ also received a co-designed educational booklet. We investigated the intervention effects on self-reported F&V intake (primary outcome), biomarkers of intake and metabolism, mood, gut symptoms, and acceptability. Post-intervention F&V intake differed between groups (p<0.001; ηp2=0.62). It was significantly higher in FV ((estimated marginal means [SE]); 8.9 [0.64] portions/day, p<0.001) and FV+FJ (6.6 [0.64], p<0.001) versus control (2.45 [0.64]), but there was no difference between FV and FV+FJ (p=0.051). Both interventions showed good acceptability. Depression symptoms differed between groups (p=0.01; ηp2=0.21); they were significantly lower in FV+FJ than control. There were no differences in anxiety or gut symptoms, nor in intake or metabolic biomarkers. A financial and educational intervention based on UK 5-a-day recommendations, with or without fruit juice/smoothies, significantly increased short-term F&V intake and benefited mood without adversely impacting health markers in the short-term. Funder: Fruit Juice Science Centre.