Salt intake per dish in the Japanese diet: a clue to help establish dietary goals at home

Typical Guidelines for Well-Balanced Diet and Science Communication in Japan and Worldwide

Numerous studies have investigated healthy diets and nutrients. Governments and scientists have communicated their findings to the public in an easy-to-understand manner, which has played a critical role in achieving citizens' well-being. Some countries have published dietary reference intakes (DRIs), whereas some academic organizations have provided scientific evidence on dietary methods, such as traditional diets. Recently, more user-friendly methods have been introduced; the Health Star Rating system and Optimized Nutri-Dense Meals are examples from Australia and Japan, respectively. Both organizations adopt a novel approach that incorporates nudges. This review summarizes the science communication regarding food policies, guidelines, and novel methods in Japan and other countries. In the food policies section, we discuss the advantages and disadvantages of the DRIs and food-based guidelines published by the government. Dietary methods widely known, such as The Mediterranean diet, Nordic diet, Japanese traditional diet, and the EAT-Lancet guidelines, were also reviewed. Finally, we discussed future methods of science communications, such as nudge.

Development of a Culinary Intervention (Cooking Class) for Salt Reduction in Japanese Home Cooking: Strategies and Assessment

Introduction

Culinary interventions (cooking classes) are a potential educational tool for salt reduction in the home diet, but their content has never been reported in detail. This study aimed to develop a cooking class for salt reduction, describe its rationale and structure so that other parties could replicate it, and preliminarily assess its impact on salt intake.

Methods

A multidisciplinary research team developed a cooking class package to reduce salt content in the Japanese home diet. The package comprised its developmental policy, teaching methodology, a menu and recipes, and an implementation manual and aimed to allow third parties to replicate and modify the content. The team took the following step-by-step developmental approach. First, traditional home meals were modeled to create strategies contributing to a target of 2 g salt/meal. Then, educational topics were developed through these strategies, and finally, a dietitian produced menus and prepared documents for the class. The impact of the cooking class was assessed in a nonrandomized study of community residents. The outcome was differences in urinary salt excretion before and after the intervention. General linear models were used to account for the possible confounders.

Results

The authors assumed 4-7 g salt/meal from analyzing typical Japanese home diets and developed 3 strategies: (1) restricting salt content in the main dish, (2) maintaining good tastes without salty dishes, and (3) balancing nutrition with low-salt dishes. On the basis of these strategies, the authors selected a total of 5 educational topics that participants could learn and apply at home: 1a, a simple and reliable technique to limit salt in a serving; 2a, excluding salty dishes; 2b, staple foods with notable flavor and aroma; 3a, flavoring without salt in side dishes; and 3b, ingredients that should be used intentionally. The team dietitian translated these educational topics into a menu and recipes for hands-on training and prepared a manual for conducting the class. The class developed using this approach was successfully overseen by a dietitian outside the research team. In the validation study, the intervention group (n=52) showed a greater decrease in urinary salt excretion than the control group (n=46), with an adjusted difference of -1.38 g (p=0.001).

Conclusions

The authors developed a cooking class package for salt reduction so that third parties could replicate and modify the class. The significant salt reduction noted in this study warrants further studies to apply this cooking class to other populations.

Impact of pre-meal immersion on multi-scale structural changes and starch digestibility of cooked dried noodles

Pre-meal immersion is a common process for both the consumption of dried noodles and development of takeaway noodles, but its impact on the structure and digestibility of dried noodles is still unclear. In this study, dried noodles cooked for the optimal time were immersed at 80 °C for different time durations. Multi-scale structural changes, including texture, molecular structure, microstructure, and in vitro starch digestibility were studied using a combination of kinetic (first-order exponential decay function, the Peleg model, and LOS plots), physicochemical, and microscopic analysis. The relationship between multi-scale structural changes and starch digestibility was derived. As the immersion progressed, the hardness first rapidly decayed and then reached equilibrium. The decay rate in the initial stage depended on the gluten content. In most cases, the immersion process caused depolymerization of gluten proteins and further gelatinization of starch granules, which was observed from an increase in the free -SH content and decrease in the short-range ordered structure, although there were fluctuations over immersion time. Structural changes resulted in the corresponding changes in substance migration. However, a high gluten content (∼15% w/w) imparted a denser microstructure to the noodles, weakening the deterioration effects compared with a low gluten content (∼10% w/w). In vitro digestion experiments proved that samples with higher gluten content had higher starch digestion rates and lower starch digestion extent during immersion. Correlation analysis revealed that there was a negative correlation between k1 and the tightness of the gel. This study helps to reveal the structural mechanisms of starch digestibility in cooked noodles during immersion.

Association between home meal preparers and salt intake in haemodialysis patients: a cross-sectional study

OBJECTIVES

This study aimed to examine the association between home meal preparer and salt intake among haemodialysis patients, including daily dietary status. We hypothesised that salt intake is higher among individuals who rely on meal preparation from others than those who prepare meals by themselves.

DESIGN

Cross-sectional study.

SETTING

Two medical facilities in Fukushima Prefecture, Japan.

PARTICIPANTS

237 haemodialysis outpatients who visited one of the medical facilities between February 2020 and August 2021 and were diagnosed with anuria, defined as urination of <100 mL/day, were the potential participants of the present study. Finally, 181 participants (131 male and 50 female) were included in the analysis.

OUTCOME MEASURE

Salt intake amount was calculated from the results of predialysis and postdialysis blood draws, using Watson's formula based on predialysis weight, predialysis serum sodium level, postdialysis weight and serum sodium level at the end of dialysis.

RESULTS

Salt intake was significantly higher in participants who relied on meal preparation from others ('relying on others') than those who prepared meals by themselves ('self-prepared') (B=1.359; 95% CI: 0.495 to 2.222). No statistical difference was found between individuals who ate out or ate takeout ('outsourcing') and those who prepared their own meals ('self-prepared'). These results were robust after adjustment for confounding factors.

CONCLUSIONS

The present study revealed an association between self-preparation of meals at home and reduced salt intake among dialysis patients. Our findings suggest that whoever is the home meal preparer is possibly a social determinant of salt intake. To improve the prognosis of haemodialysis patients, actively reaching out to the family and assessing their social environment, such as identifying the home meal preparer and, if the patient relies on others for meal preparation, conducting nutritional/dietary guidance for that person, are effective in enhancing salt reduction.

Choice of creep or maintenance fluid type and their impact on total daily ICU sodium burden in critically ill patients: A systematic review and meta-analysis

PURPOSE

Maintenance and hidden/creep fluids are a major source of fluid and sodium intake in intensive care unit (ICU) patients. Recent research indicates that low versus high sodium content maintenance fluids could decrease fluid and sodium burden. We conducted a systematic review (SR) with meta-analysis to summarize the impact of maintenance fluid choice on total daily sodium in ICU patients.

MATERIALS AND METHODS

Systematic literature search in Pubmed, Embase, the Cochrane Library and the.

CLINICAL TRIALS REGISTRY

Only controlled clinical trials were included.

EXCLUSION CRITERIA

trials on resuscitation fluids, performed in the emergency department only and in pediatric patients. Primary objective was the reduction in mean total sodium intake with low versus high sodium content maintenance/creep fluids.

RESULTS

Five studies (1105 patients) were included. Heterogeneity was high.Risk of bias was moderate. Mean daily sodium reduction was 117 mmol (95%Confidence Interval [CI] -174; -59; p < 0.001) with low versus high sodium content maintenance/creep fluids. Incidence of hyperchloremia was lower (OR 0.26; 95%CI 0.1; 0.64) with low sodium. There were no differences in the incidences of hyper-/hyponatremia and fluid balances.

CONCLUSION

Using low sodium content maintenance/creep fluids substantially reduces daily sodium burden in adult ICU patients. Significant knowledge/research gaps exist regarding relevance and safety.

TRIAL REGISTRATION

PROSPERO 2022 CRD42022300577 (February 2022).

Effects of Using a Perforated Spoon on Salt Reduction When Consuming Ramen Noodles: A Randomized Crossover Study of Japanese Male University Students

Salt reduction is a public health priority for the Japanese population. We focused on the effect of salt reduction by changing eating utensils to reduce salt consumption. As a test meal, we used ramen, which is commonly eaten by Japanese individuals and has a high salt content. In this randomized crossover study, we hypothesized that eating ramen with a perforated spoon would reduce the quantity of ramen soup and salt consumed compared to using a regular spoon without holes. Soup intake, after-meal fullness, and deliciousness were compared between eating with chopsticks and a regular spoon, and with chopsticks and a perforated spoon. In total, 36 male university students (mean age, 20.7 [standard deviation, 1.8] years) were included in the analyses. The median salt intake (25th and 75th percentiles) was significantly lower with perforated spoons (1.8 [1.5, 4.3] g) than with regular spoons (2.4 [1.8, 4.8] g; p = 0.019). There were no significant differences in after-meal fullness or deliciousness for both spoon conditions (p > 0.05). For young men, the soup intake when eating ramen with a perforated spoon was lower than that with a regular spoon; this suggests a reduction in salt intake.