Maternal intake of yoghurt and other selected fermented foods and sleep duration among preschool children in Japan: a cross-sectional study

Purpose Fermented foods have attracted attention as part of habitual dietary patterns. However, it remains unclear whether maternal intake of selected fermented foods is associated with sleep duration in pre-school children. The purpose of this study was to examine the association between maternal intake of selected fermented foods from pre-pregnancy to the present and sufficient sleep duration among four- and five-year-old children in Japan. Design/methodology/approach An online survey was conducted among 629 mothers of four-year-old children and 603 mothers of five-year-old children. Maternal intake of miso soup, natto, yoghurt and cheese was assessed. Logistic regression analysis was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for sufficient sleep duration (≥10 h/night), adjusting for maternal educational level, smoking and employment status. Findings Among four-year-old children, maternal yoghurt intake = 5 times/week was associated with sufficient sleep duration [adjusted OR 1.58 (1.03–2.41), p = 0.037] with a significant trend across categories of yoghurt intake frequency (adjusted p for trend = 0.037). No significant associations with sufficient sleep duration were observed for intake of miso soup, natto or cheese. Among five-year-old children, maternal intake of selected fermented foods was not significantly associated with sufficient sleep duration. Originality/value Herein, the authors examined maternal intake of selected fermented foods commonly consumed in Japan in relation to sleep duration among pre-school children. Maternal yoghurt intake was associated with sufficient sleep duration among four-year-old children but not among five-year-old children. These findings suggest that the association between maternal yoghurt intake and children’s sleep may differ by age.