In a small randomized trial in the United Kingdom, adults who added a serving of 100% fruit juice or a smoothie to a healthier diet reported lower depression scores after four weeks.
People who drink a glass of 100% fruit juice or a smoothie each day as part of the UK’s 5-a-day healthy eating guidance see improvements in their mental wellbeing. Image credit: Joseph Mucira.
“While most people know eating 5-a-day can be good for your health, many people struggle to,” said lead author Dr. Courtney Neal, who completed the study while at Newcastle University and is now at the University of Liverpool.
“Our trial showed that when people with low fruit and vegetable intake were provided with targeted financial and educational support to address common barriers to eating 5-a-day, they were able to make meaningful changes to their diet.”
“We found that simple, cost-effective solutions, like drinking a small glass of 100% fruit juice or a smoothie daily, could help people reach their 5-a-day, with potential benefits for mental wellbeing.”
In their study, Dr. Neal and colleagues focused on people who drink a glass of 100% fruit juice or a smoothie each day as part of the 5-a-day healthy eating guidance.
Adults with low intakes of fruit and vegetables were given support to increase their daily fruit and vegetable intake, with or without a glass of fruit juice or a smoothie, in order to meet the 5-a-day guideline.
The 42 participants were split into three groups: a control group maintaining their usual diet, a group increasing whole fruit and vegetable consumption only, and a group doing the same while also drinking a daily glass of juice or smoothie
After four weeks, both groups successfully boosted their fruit and vegetable intake, but the group that added fruit juice reported a reduction in depression scores.
Specifically, their scores on a standard depression questionnaire were 2.52 points lower on a 27-point scale compared to the control group — a modest but statistically significant difference. No adverse effects on metabolic health markers were observed.
“Given the ongoing cost of living pressures in the UK, the price of fresh produce is often a barrier for people trying to eat more fruit and vegetables,” said senior author Dr. Oliver Shannon, lecturer in nutrition and aging at Newcastle University.
“Our study shows that drinking a daily glass of fruit juice or a smoothie could be part of the solution and help people reach 5-a-day fruit and vegetable targets.”
“The finding that fruit juice drinkers had reduced depression scores is promising and worthy of further exploration, particularly in individuals experiencing poor mental wellbeing.”
“It backs up studies which report improved brain blood flow and cognitive function after people drink citrus juices.”
“Simple dietary changes — like increasing fruit intake, including through a daily glass of juice — could play a role in supporting mental wellbeing.”
The study was published May 22 in the British Journal of Nutrition.
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Courtney Neal et al. 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. British Journal of Nutrition, published online May 22, 2026; doi: 10.1017/S0007114526107569
