Traditional japanese diet score and the sustainable development goals by a global comparative ecological study

Reducing the environmental impact of the food supply is important for achieving Sustainable Development Goals (SDGs) worldwide. Previously, we developed the Traditional Japanese Diet Score (TJDS) and reported in a global ecological study that the Japanese diet is associated with reducing obesity and extending healthy life expectancy etc. We then examined the relationship between the TJDS and environmental indicators.

The average food (g/day/capita) and energy supplies (kcal/day/capita) by country were obtained from the Food and Agriculture Organization of the United Nations Statistics Division database. The TJDS was calculated from eight food groups (beneficial food components in the Japanese diet: rice, fish, soybeans, vegetables, and eggs; food components that are relatively unused in the traditional Japanese diet: wheat, milk, and red meat) by country using tertiles, and calculated the total score from - 8 to 8, with higher scores meaning greater adherence to the TJDS. We used Land Use (m²), Greenhouse gas (GHG) emissions 2007/2013 (kg CO₂eq), Acidifying emissions (g SO₂eq), Eutrophying emissions (g PO₄^3- eq), Freshwater (L), and water use (L) per food weight by Poore et al. as the environmental indicators and multiplied these indicators by each country's average food supply. We evaluated the cross-sectional and longitudinal associations between the TJDS and environmental indicators from 2010 to 2020. This study included 151 countries with populations ≥ 1 million.

Land use (β ± standard error; -0.623 ± 0.161, p < 0.001), GHG 2007 (-0.149 ± 0.057, p < 0.05), GHG 2013 (-0.183 ± 0.066, p < 0.01), Acidifying (-1.111 ± 0.369, p < 0.01), and Water use (-405.903 ± 101.416, p < 0.001) were negatively associated with TJDS, and Freshwater (45.116 ± 7.866, p < 0.001) was positively associated with TJDS after controlling for energy supply and latitude in 2010. In the longitudinal analysis, Land Use (β ± standard error; -0.116 ± 0.027, p < 0.001), GHG 2007 (-0.040 ± 0.010, p < 0.001), GHG 2013 (-0.048 ± 0.011, p < 0.001), Acidifying (-0.280 ± 0.064, p < 0.001), Eutrophying (-0.132 ± 0.062, p < 0.05), and Water use (-118.246 ± 22.826, p < 0.001) were negatively associated with TJDS after controlling for confounders.

This ecological study suggests that the traditional Japanese dietary pattern might improve SDGs except Fresh water.