Since food frequency questionnaire (FFQ) can easily grasp the habitual dietary intake and is less burdensome for both participants and researchers, it is regarded as the best method in nutritional epidemiology. It is necessary to use a FFQ that is tailored to the target population and validated, but it is difficult to exhaustively search for the FFQ that could be used in your research. You need to confirm not only if the FFQ can estimate intakes of nutrients or food groups of interest, but also if the target group where the validity is examined is comparable to your participants. In this review, we used seven databases and systematically collected FFQs that were developed for Japanese and summarized the validity of target nutrients and food groups in order to help researchers who use or modify the existing FFQ. According to the 50 selected papers, more FFQs were examined their validity for women than men. As for age groups, the number of papers that examined the validity for those in their forties and fifties was the most. For target nutrients, many FFQs estimated the intake of energy and energy-generating nutrients such as protein, carbohydrate, and fat. For food groups, more FFQ were validated for the foods that can be easily showed and answered their portion size, such as fruit and milk.

In Japan, mean birth weight has decreased and prevalence of low birth weight babies is higher than other OECD countries. We examined the relationship of maternal weight gain with dietary intake and smoking during pregnancy.

Women with singleton pregnancies without any complications who had prenatal medical check ups at a hospital in Tokyo from July 2012 to August 2013 were selected as potential participants. They were informed of appropriate weight gain according to their BMI before pregnancy and provided a leaflet regarding healthy diet at 15-20 weeks gestation. After that, midwives assessed weight gain status and gave brief dietary advice at each check-up. Seventy-six women with “insufficient” or “excess” weight gain around 28 weeks gestation were requested to record three-day food intakes and were given individualized dietary advice on their records by dieticians. Hierarchical logistic regression analysis was conducted using weight gain status from 28 weeks gestation to delivery (inadequate＝0, adequate＝1) as a dependent variable.

Regarding smoking, odds ratios could not be calculated because no couples in “adequate” group smoked. A significant promoting factor for maternal adequate weight gain was the number of days with milk and dairy products consumption (OR＝2.20 (95% CI＝1.10-4.37)) that was counted from the dietary records. In addition to their nutritional values, consumption of milk and dairy products has been pointed out as an indicator of good dietary behavior, and therefore, could be the reason for appropriate weight gain during pregnancy.

The objective of this study was to examine factors associated with calcium (Ca) intake in female high school students. Survey participants consisted of female high school students and their mothers. Survey questionnaire items comprised participants’ personal attributes, dietary intake, and awareness of osteoporosis. Valid responses (33.6%) collected from 216 mother-daughter pairs were included in the analysis. The participants’ nutrient intake and dietary intake by food group were calculated. The students were then divided into two groups based on their Ca intake: a Ca-sufficient group and a Ca-deficient group. The students’ average Ca intake was lower than the estimated average requirement (550 mg/day). Nutrient density of Ca in the Ca-deficient group was significantly lower than in the Ca-sufficient group (p＜0.01). Furthermore, multiple regression analysis (stepwise method) revealed that the students’ Ca intake was significantly associated with the intake of milk, beans, and nuts (p＜0.01). Additionally, mothers of students in the Ca-sufficient group had a significantly higher intake of milk than mothers of students in the Ca-deficient group, which was significantly associated with milk intake (p＜0.01). As regards osteoporosis awareness, a significant in ter-generational difference was observed between mothers and daughters (p＜0.01), but there was no difference between the students’ Ca-sufficient and Ca-deficient groups (p＜0.05).

Based on the aforementioned findings, it can be said that in order to increase female high school students’ Ca intake, it is necessary to educate them on the importance of maintaining bone health throughout life. Moreover, to attain and maintain behavioral changes in students, it may be necessary to examine approaches that take the actual circumstances of the students into account.