Smartphone survey data reveal the timecourse of changes in mood outcomes following vitamin C or kiwifruit intervention in adults with low vitamin C
Foods high in vitamin C have been shown to elevate mood; however, it’s unclear how long these effects will last. Conner et al. (2023) used longitudinal smartphone survey data from a three-armed placebo-controlled trial to assess changes in mood after taking a placebo (1 tablet/d), vitamin C (250 mg tablet/d), or kiwifruit (2 fruits/d). For Vitality, secondary data from the KiwiC clinical trial was analyzed. Adults with low plasma vitamin C levels (<40 ÎĽmol/l, n = 155, 63% female, ages 18–35) had a 14-day lead-in, 28-day intervention, and 14-day washout. Using smartphone questionnaires, participants assessed their mood (POMS total mood disturbance), Vitality (SF-36), flourishing (flourishing scale), physical activity, sleep amount, and sleep quality every other day. After taking kiwifruit or vitamin C supplements for two weeks, plasma vitamin C, tested every two weeks, reaches saturation. Analysis of the results showed that, compared to placebo, supplementing with kiwifruit significantly increased energy and mood in 4 days, peaked between 14 and 16 days, and boosted blossoming starting on day 14. Up until day 12, vitamin C only slightly elevated mood. These effects were more pronounced than those observed with supplementary vitamin C pills. However, they were less pronounced when confounders were taken into account. Sensitivity tests of individuals with low baseline vitamin C levels showed improved flourishing (kiwifruit only) and better mood (vitamin C and kiwifruit). The authors comment that their work emphasizes the usefulness of employing smartphone surveys to show the temporal changes in mood-related outcomes following nutritional supplementation, being the first study to utilize intensive surveys on smartphones to model the day-to-day timecourse of mood-related states following vitamin C intervention. [NPID: Nutrition, daily diary, mental health, flourishing, well-being, Vitality, diet]
Year: 2023
