A scoping review of dietary assessment questionnaires potentially suitable for assessing habitual dietary intake in the National Health and Nutrition Survey, Japan.

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.

Are popular books about diet and health written based on scientific evidence? A comparison of citations between the USA and Japan.

OBJECTIVES: To describe and compare the references cited in popular books about diet and health between the USA and Japan. DESIGN: Books were selected based on their best-seller rankings in the diet and health category of online bookstores. We identified references throughout all pages of the books and examined the number of references, reference format (identifiable or not) and presence of specific types of references, such as systematic reviews of human research. We compared the characteristics of references between the two countries and examined related factors to citation. SETTING: Cross-sectional study. PARTICIPANTS: Books (n 100 in each country). RESULTS: Among 100 books from each country, sixty-five US and sixty-six Japanese books had references. Forty-five US books cited more than 100 references, against only five Japanese books. The number of books that cited systematic reviews of human research differed between the USA (n 49) and Japan (n 9). Additionally, the number of books that provided identifiable information for all references was significantly higher in the USA (n 63) than in Japan (n 42). Books whose first authors have licences of medical doctors were more likely to cite references than those without in both countries. CONCLUSIONS: Two-thirds of books about diet and health cited references in both the USA and Japan, but Japanese books cited fewer references and were less likely to cite systematic reviews and provide identifiable references than US books. Further research into the scientific reliability of information in books about diet and health is warranted.

Development of a Diet Quality Score for Japanese and Comparison With Existing Diet Quality Scores Regarding Inadequacy of Nutrient Intake.

BACKGROUND: Few studies have explored optimal diet quality scores in Japan. OBJECTIVES: We developed a Diet Quality Score for Japanese (DQSJ) and examined the associations of DQSJ and existing diet quality scores with inadequacy of nutrient intake in Japanese adults. METHODS: Candidate components of the DQSJ were extracted from well-established diet quality scores: Healthy Eating Index-2015 (HEI-2015), Alternate Healthy Eating Index-2010 (AHEI-2010), Alternate Mediterranean Diet score (AMED), and Dietary Approaches to Stop Hypertension (DASH). From candidates, we selected the components of the DQSJ, considering potential health effects of the components (from the Global Burden of Disease Study) and dietary intake in Japan. The DQSJ included 10 components: fruits, vegetables, whole grain, dairy, nuts, legumes, fish, red and processed meat, sugar-sweetened beverages, and sodium. We calculated the DQSJ, HEI-2015, AHEI-2010, AMED, DASH, and Japanese Food Guide Spinning Top score (JFGST) based on 4-d dietary records of 392 Japanese aged 20-69 y. Inadequate intakes of 21 nutrients were assessed using the DRIs for Japanese. Logistic regression was used to examine the prevalence of inadequate nutrient intake according to quartiles of the scores. RESULTS: All examined scores except the JFGST were moderately to strongly correlated with each other (Spearman correlation coefficients: 0.52-0.84). They were inversely associated with the prevalence of inadequate intake of most nutrients (n = 16 for DQSJ and HEI-2015, n = 13 for AHEI-2010 and DASH, n = 17 for AMED, compared with n = 4 for JFGST). AMED was also positively associated with the prevalence of inadequate sodium intake, whereas no such associations were observed for the other scores. CONCLUSIONS: Similar to HEI-2015, AHEI-2010, and DASH, the DQSJ was generally associated with the low prevalence of inadequate intake of most nutrients in Japanese adults. Further evaluations against biomarkers and health outcomes are warranted.