A meal quality score based on Japanese healthy meal guidelines and its association with nutrient intakes in adult men and women

Background and objectives: To promote health and prevent lifestyle-related diseases, the Ministry of Health, Labour, and Welfare of Japan has proposed standards for a healthy meal. This study aimed to develop a meal-based diet quality score based on adherence to the standards and examine associations of the score with nutrient intakes in adult Japanese men and women. Methods: This cross-sectional study involved a secondary analysis of data from the 2017 Saitama Prefecture Nutrition Survey. We analyzed data obtained from a questionnaire and 2-day dietary records of 548 men and women aged 30–65 years with nutrient intakes within 0.5–99.5 percentile. The score for each meal (breakfast, lunch, and dinner), excluding eating out and alcoholic beverages, was calculated for six components based on the standard: grain dishes (amount of carbohydrate from grains), vegetable dishes (amount of vegetable, potato, mushroom, and seaweed intake), fish and meat dishes (amount of protein from seafood, meat, eggs, and soybeans), milk and dairy products, fruits, and salt equivalent. The scores for the first three components were adjusted based on the following sub-components: whole grain, green and yellow vegetable, red meat, and fish and soybean intakes. Each component was scored on a 10-point scale and 10 points were allotted if it met the criteria; otherwise, points were deducted and summed up to total scores (range 0–60 points) to examine associations with energy-adjusted nutrient intakes (per 650 kcal) for each meal using linear regression analysis controlled for age and sex. Results: The median total scores were 26.1 (21.2, 32.1) points for breakfast (n=540), 24.8 (19.8, 28.6) for lunch (n=360), and 27.8 (23.6, 31.8) for dinner (n=507). Some nutrients, such as dietary fiber and vitamin A, were positively associated with the total score across all meals, but fewer were associated with dinner than with breakfast and lunch. However, the total score was positively associated with better macronutrient balance and lower salt intake at dinner. Conclusions: The meal quality score developed in this study is efficacious for evaluating the quality of breakfast and lunch. However, further modification of the score is needed to evaluate the quality of dinner.