Let them eat fruit! The effect of fruit and vegetable consumption on psychological well-being in young adults: A randomized controlled trial

Abstract

This study tested the psychological benefits of a 14-day preregistered clinical intervention to increase fruit and vegetable (FV) consumption in 171 low-FV-consuming young adults (67% female, aged 18–25). Participants were randomly assigned into a diet-as-usual control condition, an ecological momentary intervention (EMI) condition involving text message reminders to increase their FV consumption plus a voucher to purchase FV, or a fruit and vegetable intervention (FVI) condition in which participants were given two additional daily servings of fresh FV to consume on top of their normal diet. Self-report outcome measures were depressive symptoms and anxiety measured pre- and post-intervention, and daily negative and positive mood, vitality, flourishing, and flourishing behaviors (curiosity, creativity, motivation) assessed nightly using a smartphone survey. Vitamin C and carotenoids were measured from blood samples pre- and post-intervention, and psychological expectancies about the benefits of FV were measured post-intervention to test as mediators of psychological change. Only participants in the FVI condition showed improvements to their psychological well-being with increases in vitality, flourishing, and motivation across the 14-days relative to the other groups. No changes were found for depressive symptoms, anxiety, or mood. Intervention benefits were not mediated by vitamin C, carotenoids, or psychological expectancies. We conclude that providing young adults with high-quality FV, rather than reminding them to eat more FV (with a voucher to purchase FV), resulted in significant short-term improvements to their psychological well-being. These results provide initial proof-of-concept that giving young adults fresh fruit and vegetables to eat can have psychological benefits even over a brief period of time.Trial registration: Australian New Zealand Clinical Trials Registry ACTRN12615000183583

Bidirectional relationship of stress and affect with physical activity and healthy eating

“…Earlier studies explored the reverse relationship mainly for affect changes after the consumption of certain food types, mainly carbohydrates, meaning that people feel better after consumption and reduce their stress level (Christensen & Pettijohn, 2001;Evers, Stok, & de Ridder, 2010;Spring, Chiodo, & Bowen, 1987;Sproesser, Schupp, & Renner, 2014;Taut, Renner, & Baban, 2012). Likewise, fruits and vegetables consumption seems to lead to higher subsequent positive affect (Conner, Brookie, Carr, Mainvil, & Vissers, 2017;Conner, Brookie, Richardson, & Polak, 2015;White, Horwath, & Conner, 2013).…”

“…As an additional goal, we considered the role of positive and negative affect, as stress and affect have frequently been intermingled and seem to have combined effects. Studies indicate that affect seems to have an influence on an individual's activity level (e.g., Cameron, Bertenshaw, & Sheeran, 2017;Herman et al, 2002;Schwerdtfeger, Eberhardt, Chmitorz, & Schaller, 2010;Wallbott, 1998) and eating behaviour (for an overview, see Cardi, Leppanen, & Treasure, 2015;Macht, 2008) and that salutogenic behaviours have a positive effect on affect (e.g., Conner et al, 2017;Dunton et al, 2014;Lathia, Sandstrom, Mascolo, & Rentfrow, 2017;White et al, 2013;Wichers et al, 2012).…”

Life satisfaction and diet in transition: evidence from the Russian Longitudinal Monitoring Survey

“…Conner et al. () in a clinical trial using young adults of Australia and New Zealand also find evidence that fruit and vegetables can have psychological benefits over short periods of time.…”

“…There is growing literature that explores the psychological effects of macro, and especially micronutrients consumed through the everyday diet (e.g., Blanchflower et al., ; Conner et al., ; Mujcic and Oswald, ; Rooney et al., ). In our study, the focus is somewhat different but, nevertheless, we recognize that the biochemical effect of food on psychological health and life satisfaction could be an important channel.…”

Advances in the Value Addition to Foods-recent Trends

“…that are capable of alleviating modern life-style related disorders and diseases. As a natural source of these phytochemicals, especially the consumption of whole foods has been suggested to be of health benefit 4 . Micronutrients like vitamins and minerals have many biological functions.…”