Differences in Dietary Intake of Women with Standard Weight but Varying Body Fat Percentages in Japan

“Hidden obese people” have a high body fat percentage (BFP) despite having a normal BMI (18.5 30%) (n = 160) and standard physique (18.5 <BMI ? 25.0 and BFP <30%) (n = 376) were compared using Student’s t-test or Welch’s t-test. The participants with hidden obesity physique have lower intake of energy (p = 0.044) and fat (p = 0.036) and a higher intake of carbohydrates (p = 0.023), cereals (p = 0.009) and sugary beverages (p = 0.020). This study suggests that a reduction in carbohydrate-dense foods is effective in preventing hidden obesity

Validity of a food frequency questionnaire to estimate long-chain polyunsaturated fatty acid intake among Japanese women in early and late pregnancy

Background: The relative validity of food frequency questionnaires for estimating long-chain polyunsaturated fatty acid (LC-PUFA) intake among pregnant Japanese women is currently unclear. The aim of this study was to verify the external validity of a food frequency questionnaire, originally developed for non-pregnant adults, to assess the dietary intake of LC-PUFA using dietary records and serum phospholipid levels among Japanese women in early and late pregnancy. Methods: A validation study involving 188 participants in early pregnancy and 169 participants in late pregnancy was conducted. Intake LC-PUFA was estimated using a food frequency questionnaire and evaluated using a 3-day dietary record and serum phospholipid concentrations in both early and late pregnancy. Results: The food frequency questionnaire provided estimates of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) intake with higher precision than dietary records in both early and late pregnancy. Significant correlations were observed for LC-PUFA intake estimated using dietary records in both early and late pregnancy, particularly for EPA and DHA (correlation coefficients ranged from 0.34 to 0.40, p < 0.0001). Similarly, high correlations for EPA and DHA in serum phospholipid composition were also observed in both early and late pregnancy (correlation coefficients ranged 0.27 to 0.34, p < 0.0001). Conclusions: Our findings suggest that the food frequency questionnaire, which was originally designed for non-pregnant adults and was evaluated in this study against dietary records and biological markers, has good validity for assessing LC-PUFA intake, especially EPA and DHA intake, among Japanese women in early and late pregnancy

Seasonal misclassification error and magnitude of true between-person variation in dietary nutrient intake: a random coefficients analysis and implications for the Japan Public Health Center (JPHC) Cohort Study

OBJECTIVE: We examine (1) the extent to which seasonal diet assessments correctly classify individuals with respect to their usual nutrient intake, and (2) whether the magnitude of true variation in intake between individuals is seasonal. These effects could lead, respectively, to bias in estimates of relative risk for associations between usual nutrient exposure and disease, and to an increase in required sample size. SUBJECTS AND SETTING: One hundred and twenty-seven families in four regions of the Japan Public Health Center (JPHC) Cohort Study. DESIGN: On average, 48 weighed daily food records were collected per family over six seasons of 1994 and 1995. RESULTS: A random slopes regression model was used to predict the correlation between seasonal and annual average intakes, and to estimate true between-person variation in intakes by season. Mean vitamin C intake was greatest in summer and autumn, and seasonal variation was attributable to the consumption of fruit and vegetables. Predicted correlations between seasonal and annual average vitamin C intake ranged from 0.62 to 0.87, with greatest correlations in summer and autumn. True between-person variation in vitamin C intake was also strongly seasonal, ranging from 45 to 78% of total variance, and was again greatest in summer and autumn. These effects were less seasonal among energy and 13 other nutrients. CONCLUSIONS: It may be possible substantially to reduce both seasonal misclassification of individuals with respect to their usual vitamin C intake, and required sample size, by asking subjects to report high-season intake of fruit and vegetables in the JPHC Study