Overview
- The peer‑reviewed trial published 26 May 2026 in the British Journal of Nutrition randomly assigned 42 UK adults with low fruit and veg intake to three groups for a four‑week intervention.
- Participants who added one daily glass of 100% fruit juice or a smoothie scored 2.52 points lower on the PHQ‑9 depression scale than the control group, a modest but statistically significant change on a 27‑point measure.
- Both intervention groups increased estimated fibre intake by about 8–10 grams per day, showing the juice did not stop participants from eating more whole fruit and vegetables.
- Researchers reported no adverse changes in short‑term metabolic health markers for the juice group over four weeks, though the study was too brief to assess longer‑term risks tied to free sugars.
- Authors and commentators say the result is promising for people who struggle to meet 5‑a‑day because of cost or access, but they note the trial’s small size, short duration and industry funding from the Fruit Juice Science Centre and call for larger, longer, independent studies.