Consumption of meals prepared away from home is associated with inadequacy of dietary fiber, vitamin C and mineral intake among Japanese adults: analysis from the 2015 National Health and Nutrition Survey

Background Consumption of home-prepared meals may lead to better nutritional intake. Few studies have examined the association between the frequency of consuming meals prepared away from home and the inadequacy of nutritional intake based on nutritional standards and food group intake. We therefore aimed to investigate this issue among Japanese adults. Methods This study was a secondary analysis of the 2015 National Health and Nutrition Survey in Japan, involving 921 men and 1300 women aged 18-64 years, conducted as a cross-sectional survey. The frequency of consuming meals prepared away from home was defined using two questions inquiring about the frequency of eating out and take-away meals. Data on dietary intake were collected using a one-day semi-weighed household dietary record. Participants were stratified into three groups based on the frequency of consuming meals prepared away from home (High, Moderate, Low). The inadequacy of each nutrient intake was assessed by comparing estimated average requirement (EAR) level for 14 nutrients and the range of the dietary goal (DG) for seven nutrients according to the 2015 version of the Dietary Reference Intakes for Japanese. Group differences in nutrients adequacy were assessed using the covariate and logistic regression analysis. Food intake was also compared across the groups by classifying each food item into 17 groups based on Standard Tables of Food Composition. Results The proportion of participants who consumed home-prepared meals almost every day were 34.9% among men and 46.8% among women, and the proportion of those consuming a higher frequency of meals prepared away from home were 14.7 and 6.3%, respectively. A higher frequency of consuming meals prepared away from home was associated with inadequacy of dietary fiber, vitamin C and minerals (iron, magnesium and potassium) intake, and with lower intake of vegetables and higher intake of fat and oils. Conclusions High frequency of consuming meals prepared away from home was associated with insufficient intake of dietary fiber, vitamin C and multiple minerals among Japanese adults. These nutrients may be the potential target of interventions aimed at improving nutrient intake in individuals who predominantly eat food prepared away from home.