The purpose of this study was to investigate if there are differences in nutritional knowledge, beliefs regarding sodium intake, self-efficacy, eating behaviors, and eating environment according to the stages of adequate sodium intake behavior in young adults. The online survey was conducted among adults aged 18 to 30 years old at nine universities in Seoul from August 2021 to March 2022. The questionnaire included items to measure general characteristics, stages of change in adequate sodium intake, nutritional knowledge (12 items), beliefs regarding sodium intake (14 items), self-efficacy (13 items), eating behavior (25 items), and eating environment (8 items). Data were collected from undergraduate or graduate students, and data from 351 respondents were used in data analysis, excluding the data with insufficient responses and data beyond the target age category. Statistical analysis was done using SPSS Statistics 24.0 program. This study was approved by the IRB of Seoul women's university (IRB-2021A-26). Subjects were divided into two groups according to the stages of change in adequate sodium intake. The precontemplation, contemplation, and preparation stages were grouped into the preaction stage, and the action stage and maintenance stage were classified as the action stage. Subjects were 23.6 years old on average, and the body weight was significantly lower in the action stage (59.4kg) than the preaction stage (62.7kg, p<0.05). The interest in health and nutrition, perception on one's dietary life were higher in the preaction stage (p<0.01) and the preference for salty food was lower (p<0.001) in the action stage than in the preaction stage. The percentage of those with the unbalanced meal was lower in the action stage than in the preaction stage (p<0.01).
The total score of nutritional knowledge was higher in the action stage (9.5 points) than in the preaction stage (8.9 points, p<0.05). Subjects in the action stage had higher nutritional knowledge related to the sodium intake subscale than those in the preaction stage(p<0.05). The percentage of correct answers for vitamin A rich food (p<0.01), foods high in sodium (p<0.05), and the role of potassium in the body (p<0.05) was higher in the action stage than in the preaction stage. The action stage, compared to the preaction stage, scored higher on the beliefs of the results of adequate sodium intake (p<0.001). More specifically, the preaction stage agreed more strongly on the disadvantages of eating adequate sodium than the action stage (28.9 points vs 26.4 points, p<0.001).
The total score of self-efficacy was higher in the action stage (46.7 points) than in the preaction stage (41.9 points, p<0.05). Self-efficacy for healthy eating behaviors (p<0.001) and self-efficacy for controlling sodium intake (p<0.01) subscale were higher in the action stage than in the preaction stage. The eating behavior was more desirable in the action stage (67 points) than in the preaction stage (59.6 points, p<0.001). The score of eating behavior subscales was higher in the action stage than in the preaction stage (general eating behaviors, behaviors regarding sodium check, p<0.001). Behaviors regarding sodium intake subscale were lower in the action stage than in the preaction stage (p<0.001). This means that eating behaviors were more desirable in the action stage than in the preaction stage, and the eating behaviors of increasing sodium intake were lower. The social environment was less important in the action stage than in the preaction stage. (p<0.01). In the action stage, the physical environment is well-formed compared to the preaction stage (p<0.05). When examined by each eating environment item, the preaction stage was more influenced by friends or experts than the action stage, and the eating environment at home was not well-formed.
As a result of this study, the stages of behavior change showed significantly associated with nutrition knowledge, beliefs regarding sodium intake, self-efficacy, eating behaviors, and eating environment. Nutrition education might be planned for the adequate sodium intake in the preaction stage. First, it is necessary to develop a program that can lower the barriers to practice desirable eating behaviors by improving the disadvantages of eating adequate sodium (not delicious, eating less of my favorite foods). In addition, it is necessary to increase self-efficacy by setting goals to reduce sodium intake step by step (e.g. reducing the intake of Kimchi at restaurants, checking the sodium content of processed foods, etc.). Second, it is necessary to develop nutrition education that can recognize the importance of adequate sodium intake by raising the level of nutrition knowledge. In the case of the action stage, it is necessary to develop the program that can continuously maintain behaviors through low-salt club formation, low-salt restaurant visits, low-salt recipe sharing, and self-monitoring (e.g., diet diary).