Development of a culinary intervention (cooking class) for salt reduction in Japanese home cooking – Strategies and assessment

Purpose 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. We 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 effect 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. Firstly, traditional home meals were modeled to create strategies contributing to a target of 2 g salt/meal. Then, educational topics were developed via these strategies, and finally, a dietitian produced menus and prepared documents for the class. The effect of the cooking class was assessed in a non-randomized 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 We assumed 4-7 g salt/meal from analyzing typical Japanese home diets and developed three strategies: 1) restricting salt content in the main dish, 2) maintaining good tastes without salty dishes, and 3) balancing nutrition with low-salt dishes. Based on these strategies, we selected a total of five 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). Conclusion We 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.