Dietary intake is associated with human chronotype as assessed by both morningness-eveningness score and preferred midpoint of sleep in young Japanese women.

We analyzed the association between dietary intake and chronotype as assessed by both Morningness-Eveningness Questionnaire (MEQ) score and preferred midpoint of sleep in 112 young Japanese women. Dietary intake was assessed by a brief, self-administered diet history questionnaire. A lower MEQ score (evening-type tendency) showed a significant association with a lower energy-adjusted intake of protein, calcium, magnesium, zinc, vitamins (D, riboflavin, and B(6)), and vegetables, and with a higher intake of noodles. Furthermore, a later midpoint of sleep showed a significant association with a lower energy-adjusted intake of protein, cholesterol, potassium, calcium, magnesium, zinc, vitamins (D, riboflavin, B(6), and B(12)), soy, fish and shellfish, and eggs, and with a higher intake of noodles, bread, and confections. These data suggest that evening chronotype is associated with inadequate dietary habits such as low vitamin and mineral intakes.