Mixed
Increasing the daily quantity and frequency of fruit and vegetable consumption leads to a dose-response improvement in mental well-being (GHQ-12) and subjective life satisfaction, independent of time-invariant confounders.
To boost your mental well-being, aim to increase both how many portions of fruits and vegetables you eat on days you consume them, and how many days per week you eat them. You do not need to reach a specific 'magic number' like five portions; the study shows a linear, dose-response benefit where even small increases in quantity and frequency correlate with higher mental well-being scores over time.
Fixed effects regressions show that mental well-being (GHQ-12) responds in a dose-response fashion to increases in both the quantity and the frequency of fruit and vegetables consumed. This relationship is robust to the use of subjective well-being (life satisfaction) instead of mental well-being.
Why this rating
High-quality longitudinal panel data (UKHLS, n>50,000) with fixed-effects controls for time-invariant unobserved heterogeneity, though it remains observational and not a randomized controlled trial.
Source
Lettuce be happy: A longitudinal UK study on the relationship between fruit and vegetable consumption and well-being
Neel Ocean et al. · Social Science & Medicine · 2019
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