Psychological stress and (poly)phenol intake in free-living healthy adults: an ecological momentary assessment study

Stress can impact physical and psychological health, partially driven by a deterioration in dietary choices during periods of stress. Crucially, the nutritional composition of food choices made in the context of stress may protect from or exacerbate its impact on health. Dietary (poly)phenols can be cardioprotective during stress but whether individuals tend to consume (poly)phenol-rich foods during stressful periods is unknown. This study aimed to investigate within- and between-person associations between daily stress and (poly)phenol intake in a free-living environment. Daily levels of perceived stress and psychological wellbeing (anxiety, depression, positivity, energy, fatigue), (poly)phenol intake (including flavonoids and phenolic acids sub-groups), (poly)phenol-rich food intake (fruit and vegetables, tea and coffee, red wine), and diet composition (fat, saturated fat, sugar, fibre) were measured using ecological momentary assessment (EMA) in 67 young healthy participants over 7 days. Multilevel linear mixed models examined within- and between-person associations between daily perceived stress, psychological wellbeing and (poly)phenol intake, (poly)phenol-rich food intake and dietary composition. Higher stress at the within-person level and symptoms of depression at the between-person level were associated with more consumption of tea and coffee. This was paralleled by a tendency to increase polyphenol (p = 0.070) and phenolic acid (p = 0.064) intake during stress. Furthermore, the association between stress and tea and coffee consumption was stronger in participants with higher habitual stress. A lower perception of feeling positive at the within-person level was associated with higher saturated fat and sugar consumption, and higher fatigue at the between-person level was associated with increased fat intake. Our findings suggest that when perceived stress is higher, individuals show preference for consumption of (poly)phenol-rich beverages such as tea and coffee. Future research should investigate whether tea and/or coffee are a viable strategy to deliver (poly)phenols during stressful periods with the ultimate goal of protecting cardiovascular health.