RESUMEN
OBJECTIVES: Serum diamine oxidase (DAO) level is employed as a useful marker of intestinal mucosal integrity. As reported previously, the range of serum DAO levels in women is wider than that in men. We hypothesized that the menstrual cycle may affect DAO levels. DESIGN AND METHODS: Thirty-six women of Japanese descent were recruited. All participants, aged 20-29 years, were healthy. Food surveys utilized in this study were based on questionnaires validated by dietitians. Complete blood counts, biochemical parameters, female hormones, and serum DAO levels during the follicular and luteal phases were measured in each subject. RESULTS: Biochemical parameters, except for DAO levels, were comparable between the two phases. However, serum DAO levels during the luteal phase were significantly higher than those during the follicular phase. CONCLUSIONS: Serum DAO levels were influenced by the menstrual cycle. Furthermore, our findings suggest that serum DAO levels should be interpreted cautiously in premenopausal women.