中出 麻紀子

Background/Objectives: In a demographic increasingly at risk of obesity and hypertension, whether dietary behaviours associated with hypertension prevention, such as restricting salt intake and consuming potassium-rich fruits and vegetables, contribute to obesity prevention is unclear. Therefore, we aimed to investigate the structural associations of dietary salt restriction practices with body mass index (BMI) and the mediating role of the dietary sodium/potassium (Na/K) ratio in middle-aged and older Japanese adults. Methods: This cross-sectional survey included 418 participants aged 40-69 years, residing in Hyogo, Japan. Simultaneous multi-population analysis according to sex was performed using a hypothetical model to explore associations of dietary salt restriction practices with BMI, mediated by the dietary Na/K ratio, as well as the role of BMI-related eating behaviours. Results: Dietary salt restriction was associated with a low dietary Na/K ratio (standardised estimate: -0.21, p = 0.001 for men; -0.19, p = 0.002 for women) in both sexes. Dietary salt restriction was associated with lower values of BMI in men (0.21, p = 0.004), mediated by the Na/K ratio; a direct but relatively weak association with lower values of BMI was observed in women (-0.16, p = 0.018). In men, eating out frequently was associated with higher values of BMI (0.20, p = 0.005). Conclusions: Dietary salt restriction practices in middle-aged and older adults may contribute to obesity prevention, and dietary Na/K ratio may play a mediating role in men but not in women; additionally, eating out was associated with higher values of BMI in men.

Few young Japanese adults regularly consume a well-balanced diet composed of staples, main courses, and sides. We hypothesised that adopting the recommended planetary health diet with regular breakfast consumption would promote well-balanced diets among young Japanese male undergraduates. This study aimed to examine the structural association between the planetary health diet with regular breakfast consumption and a well-balanced diet intake. This cross-sectional study included 142 male engineering undergraduates who completed a 2022 online questionnaire via Google Forms at a public university in Hyogo Prefecture. The planetary health diet comprises the consumption of the recommended eight items. A covariance structure analysis was performed in a hypothetical model with factors (regular breakfast consumption and eight items) potentially associated with the intake of a well-balanced diet at least twice daily. After excluding chicken dishes and nuts from the eight recommended items of the planetary health diet, goodness-of-fit became acceptable. Frequent consumption of the remaining six recommended items (fish, eggs, soybeans/soybean products, dairy foods, vegetables, and fruits) was significantly positively correlated with regular breakfast consumption and a significant positive path to a well-balanced diet. Among male university students, regular breakfast consumption and the planetary health diet may lead to a well-balanced diet.

Abstract This scoping review aimed to identify questionnaire-based dietary assessment methods for use in the National Health and Nutrition Survey (NHNS) in Japan. The search was conducted in three databases (PubMed, Web of Science, and Ichushi) to identify questionnaire such as food frequency questionnaire and dietary history questionnaire validated against dietary recalls or food records for the intakes of both food groups and nutrients among Japanese adults. Study quality was assessed based on previously developed criteria. We extracted the questionnaire characteristics and the design and results of the validation studies. We identified 11 questionnaires, with the number of food items ranging from 40 to 196, from 32 articles of good quality. In the validation studies, participants were aged 30–76 years and 90% of the articles used ≥3 d dietary records as reference. The number of nutrients and food groups with a group-level intake difference within 20% against the reference method ranged from 1 to 30 and 1 to 11, respectively. The range of mean correlation coefficients between questionnaire and reference methods were 0.35–0.57 for nutrients and 0.28–0.52 for food groups. When selecting a survey instrument in the NHNS from the 11 existing questionnaires identified in this study, it is important to select one with high group-level comparison and correlation coefficient values on the intended assessment items after scrutinizing the design and results of the validation study. This review may serve as a reference for future studies that explore dietary assessment tools used for assessing dietary intake in specific representative populations.

This study comprehensively examined the associations between shokuiku (food and nutrition education) during school years, current well-balanced diets, and current eating and lifestyle behaviours of Japanese female university students. A hypothetical model was developed using factors potentially associated with well-balanced diets. A simultaneous multipopulational analysis was performed according to the living arrangements of 148 female Japanese students (48.6% living alone) from a registered dietitian course. The analysis showed acceptable goodness of fit and a significant positive path from shokuiku during school years (living alone: standardised estimate 0.29, p = 0.004; with family: 0.32, p = 0.006) and a negative path from eating out frequency (-0.19, p = 0.039; -0.24, p = 0.017) towards a well-balanced diet. A significant negative path was identified from late bedtimes (-0.45, p < 0.001) and home meal replacement use frequency (-0.24, p = 0.010) in those living alone and from late-night snacking frequency (-0.27, p = 0.007) in those living with family. Well-balanced diets in female university students may be positively associated with shokuiku during school years and limited by a late bedtime, eating out, and home meal replacement use in those living alone, and by late-night snacking and eating out in those living with family.

Development of an accurate and efficient dietary method is required for national nutrition surveys. Some countries conduct dietary surveys and combine 24-h dietary records or 24-h dietary recalls with dietary questionnaires. This scoping review aimed to summarize studies that used results from national surveys that combined detailed dietary surveys (dietary records or 24-h dietary recall) and dietary questionnaires and identify the purpose of combining the two methods. The PubMed database and manual searches were used for the literature review. We extracted 58 articles from 16 national nutrition surveys from 14 countries. Most studies used 24-h dietary recall for detailed dietary surveys and the food frequency questionnaire (FFQ) or food propensity questionnaire (FPQ) for questionnaire surveys. Among 37 studies from eight countries, the purpose of combining the two dietary survey methods was to estimate energy and nutrient intakes from detailed dietary surveys and habitual food intake from questionnaires. These findings are useful as a reference when introducing new dietary survey methods in future national nutrition surveys.

In Japan, the amount of vegetable intake in young adults, especially at breakfast, is low. We aimed to examine the factors associated with vegetable intake at breakfast among young adults. In 2016, a self-administered questionnaire survey was conducted at a Japanese university. The questionnaire measured the frequency of ≥70 g vegetable intake at breakfast, lifestyle, eating habits, environmental factors, knowledge and attitudes (including the variable "Perceived behavior control (PBC)", from the Theory of Planned Behavior). The data of 1,455 male students who usually ate breakfast were analyzed. They were divided into two groups based on the median of the frequency of vegetable intake and the above factors were compared using a chi-squared test by living condition. The significant factors were subsequently entered into a logistic regression analysis as independent variables. Eating breakfast with family or friends and PBC were positively associated with vegetable intake in students living with their family. Often doing one's own cooking, having knowledge about a well-balanced diet, and PBC were positively associated with vegetable intake in students living alone. Along with PBC, different factors pertaining to an individual's living condition may need to be considered to increase vegetable intake at breakfast.

Purpose. To examine behavioral factors related to successful weight maintenance. Methods. Subjects were 90 middle-aged participants who attended a weight loss program and were followed for one year. The subjects were classified into either successful weight maintainers (maintained a weight loss of 5% or more from their initial weight for one year) (SWM) or unsuccessful weight maintainers (USWM), and weight control practice, stress, obstacles, support, and self-efficacy during the program and follow-up period were compared. Results. SWM had mean loss of 12% from their initial weight during the program. They showed a greater improvement in their regularity of eating, walked more, and felt less stress regarding their increased physical activity than the USWM. During the follow-up period, significantly more SWM participants had self-efficacy (for measuring weight, practicing dietary objective, and assessing the practice and keeping records), actually kept records and measured weight more than the USWM participants. In contrast, more USWM participants felt stress about measuring weight. Conclusion. In addition to a substantial initial weight loss due to an increased amount of physical activity, having a higher self-efficacy and consistently keeping records of one's activities, as well as regularly weighing themselves, may be important for successful weight maintenance.