A Japanese diet with low glycaemic index and glycaemic load is associated with both favourable and unfavourable aspects of dietary intake patterns in three generations of women

Effects of individualized dietary advice compared with conventional dietary advice for adults with type 2 diabetes: A randomized controlled trial

BACKGROUND AND AIMS

To investigate the superiority of individualized dietary advice based on dietary assessment for patients with type 2 diabetes.

METHODS AND RESULTS

A total of 136 Japanese adults with type 2 diabetes were randomized into either individualized or conventional dietary advice groups after dietary assessment using a self-administered brief-type diet history questionnaire. Both participants received three 30-min face-to-face dietary advice sessions by dietitians at 1, 3, and 5 months from study entry. The individualized group received dietary advice based on individual dietary intakes. The conventional group received dietary advice using generalized pamphlets. The primary outcome was the change in HbA1c over 6 months, and secondary outcomes were changes in weight, serum triglyceride, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and dietary intakes. In total, 126 participants were included in the analysis. After adjustment for age, sex, and baseline measurements, HbA1c significantly decreased larger in the individualized group [-1.1%, (95% CI: -1.3 to -0.8)] than the conventional group [-0.7% (95% CI: -1.0 to -0.4)] (P = 0.0495). The individualized group significantly decreased weight, serum triglyceride, and LDL-C, and significantly increased HDL-C, without a significant difference to the conventional group. In dietary changes, the individualized group decreased intakes of energy, confectioneries, meats, oil and fats, and sugar-sweetened beverages. The conventional group decreased alcohol intake and increased total fat and saturated fatty acid intakes.

CONCLUSIONS

Individualized dietary advice among patients with type 2 diabetes was superior to conventional dietary advice in lowering HbA1c.

TRIAL REGISTRATION

UMIN000037268 (https://www.umin.ac.jp/ctr/index.htm) in July 4, 2019.

Web-Based Personalized Nutrition System for Delivering Dietary Feedback Based on Behavior Change Techniques: Development and Pilot Study among Dietitians

Given the complex and varied nature of individual characteristics influencing dietary behaviors, personalized dietary advice may be more effective than generalized “one-size-fits-all” advice. In this paper, we describe a web-based personalized nutrition system for improving the quality of overall diet in the general adult population. The development process included identification of appropriate behavior change techniques, modification of dietary assessment method (Meal-based Diet History Questionnaire; MDHQ), selection of dietary components, and a personalized dietary feedback tool. A pilot study was conducted online among 255 dietitians. Each completed the MDHQ, received his/her own dietary feedback report, and evaluated the relevance of the report based on 12 questions using a 5-point Likert scale from “totally disagree” (score 1) to “totally agree” (score 5). The mean value of overall acceptability score of dietary feedback report was 4.2. The acceptability score was, on average, higher in plausible energy reporters (compared with implausible energy reporters), participants who printed out the report (compared with those who did not), and those spending ≥20 min to read the report (compared with those spending <20 min). This is the first attempt to develop a web-based personalized nutrition system in Japan, where dietitians were broadly supportive of the dietary feedback report.

Dietary glycemic index, glycemic load, and endometrial cancer risk: The Japan Public Health Center-based Prospective Study

Evidence supporting the association of glycemic index (GI) and glycemic load (GL) with the risk of endometrial cancer is controversial and reports from Asia were limited. Therefore, we aimed to investigate the association in Japanese women. We evaluated 52 460 women in the Japan Public Health Center-based Prospective Study aged 45-74 years who responded to the 5-year follow-up survey. GI and GL were calculated from a validated food frequency questionnaire, and the participants were divided into three groups by GI and GL. The hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated with the Cox proportional hazard model adjusted for potential confounding factors. As a result, within 15.5 years of follow-up, 166 new cases of endometrial cancer were identified. Compared with the lowest GI and GL tertile groups, the HR of the risk of endometrial cancer in the highest GI tertile group was 0.80 (95% CI, 0.53-1.20; Ptrend  = .33), and that of the highest GL tertile group was 0.79 (95% CI, 0.52-1.19; Ptrend  = .82). The results were unchanged after stratification by body mass index, coffee consumption, and history of diabetes. In conclusion, we did not find any significant association between GI and GL with the risk of endometrial cancer. Further research is required to clarify the association.

Dietary glycemic index, glycemic load and mortality: Japan Public Health Center-based prospective study

PURPOSE

Long-term associations of dietary glycemic index (GI) and glycemic load (GL) with mortality outcomes remain unclear.

METHODS

The present analysis included 72,783 participants of the Japan Public Health Center-based Prospective Study. Participants who responded to the 5-year follow-up questionnaire in 1995-1999 were followed-up until December 2015. We estimated the risk of total and cause-specific mortality associated with GI and GL using Cox proportional hazards regression models.

RESULTS

During 1,244,553 person years of follow-up, 7535 men and 4913 women died. GI was positively associated with all-cause mortality. As compared with the lowest quartile, the multivariable HR for those who had the highest quartile of GI was 1.14 (95% CI 1.08-1.20). The HRs for death comparing the highest with the lowest quartile were 1.28 (95% CI 1.14-1.42) for circulatory system diseases, 1.33 (95% CI 1.14-1.55) for heart disease, 1.32 (95% CI 1.11-1.57) for cerebrovascular disease, and 1.45 (95% CI 1.18-1.78) for respiratory diseases. GI was not associated with mortality risks of cancer and digestive diseases. GL showed a null association with all-cause mortality (highest vs lowest quartile; HR 1.04; 95% CI 0.96-1.12). However, among those who had the highest quartile of GL, the HRs for death from circulatory system diseases was 1.24 (95% CI 1.05-1.46), cerebrovascular disease was 1.34 (95% CI 1.03-1.74), and respiratory diseases was 1.35 (95% CI 1.00-1.82), as compared with the lowest quartile.

CONCLUSION

In this large prospective cohort study, dietary GI and GL were associated with mortality risks.

Establishment of a Meal Coding System for the Characterization of Meal-Based Dietary Patterns in Japan

Background: Most studies on dietary patterns to date have focused on the daily intake of individual foods, rather than the combination of foods simultaneously consumed during specific eating occasions (breakfast, lunch, dinner, and snacks).Objective: We aimed to establish a meal coding system for characterizing meal-based dietary patterns in Japan.Methods: Dietary data used were from the 2012 National Health and Nutrition Survey, Japan, in which 1-d weighed dietary records were collected from 26,361 adults aged ≥20 y. The food diary was based on a typical Japanese eating pattern, which comprised breakfast, lunch, dinner, and snacks; these eating occasions were prescribed in the diary. A total of 94,439 eating occasions (25,187 breakfasts, 25,888 lunches, 26,248 dinners, and 17,116 snacks) were identified. For all meal types, common food group combinations were identified to produce a range of generic meals. These generic meals were then used in principal components analysis to establish meal patterns.Results: In total, 94 generic meals (24 breakfasts, 27 lunches, 26 dinners, and 17 snacks) were identified. The most frequently identified food group combination for all 3 main meals was "rice and vegetables" (9 generic meals for breakfast, 12 for lunch, and 16 for dinner), whereas "confectioneries and nonalcoholic and noncaloric beverages" was the most prevalent combination for snacks (3 generic meals). In total, 19 meal patterns were established by using principal components analysis, which accounted for 24.1% of total variance. Patterns ranged considerably with regard to meal-type inclusion and the selection of staple foods (rice, bread, and noodles) and beverages, as well as with regard to meal constituents.Conclusions: With the use of a meal coding system, we identified a wide range of meal-based dietary patterns in Japanese adults. This meal coding system may be useful in capturing and investigating the complex nature of Japanese meals and food combination patterns.

Changes in dietary glycemic index and glycemic load in Australian adults from 1995 to 2012

Background: Australians have used the glycemic index (GI) since 1995; however, there are no data on changes in carbohydrate quality over time.Objectives: The aim was to compare average dietary GI and glycemic load (GL), and contributing carbohydrate foods, in the 2 most recent national dietary surveys.Design: Dietary data from adult participants of national nutrition surveys conducted in 1995 (the 1995 Australian National Nutrition Survey; n = 8703) and 2012 (the 2011-2012 National Nutrition and Physical Activity Survey; n = 6278), collected by a single 24-h recall, were analyzed. The differences in mean dietary GI and GL between surveys were compared by using 1-factor ANOVA. The main sources of dietary GL in the 2 surveys were also assessed. Multiple linear regression was performed to examine the contributions of the food groups to interindividual variations in dietary GI and GL.Results: Overall, dietary GI and GL decreased by 5% and 12%, respectively, from 1995 to 2012 (GI on glucose standard: 56.5 ± 6.2 compared with 53.9 ± 6.8, respectively; GL: 153.3 ± 62.1 compared with 135.4 ± 58.5, respectively; both P < 0.001). Breads were the main contributor to GL at both time points. Potatoes and sweetened beverages contributed less, whereas cereal-based dishes contributed more in 2012 than in 1995. The top 20 GL-contributing food groups explained less interindividual variation in dietary GI (R²: 0.376 compared with 0.290) and GL (R²: 0.825 compared with 0.770) in 2012 than in 1995.Conclusion: Although the average dietary GI and GL declined between 1995 and 2012, trends in specific carbohydrate foods suggest that Australians are avoiding potatoes and sugary beverages in favor of a greater variety of carbohydrate foods, particularly cereal products.