Background/objectives: The prolongation of healthy life expectancy (HALE) is a core issue of health policy in many countries. The purpose of this study is to clarify the relationship between dietary diversity and HALE using international databases.

Materials/methods: HALE data by country were derived from the Global Burden of Disease (GBD) 2015 database. Average food supply (g/day/capita) and energy supply (kcal/day/capita) by country, excluding loss between production and household, were obtained from the Food and Agriculture Organization of the United Nations Statistics Division database. Each food was sorted across 12 food groups, and dietary diversity was obtained from food groups using the Quantitative Index for Dietary Diversity (QUANTIDD). The cross-sectional and longitudinal associations between QUANTIDD and HALE were examined in the countries with populations of one million or greater.

Results: Cross-sectional analysis showed that HALE was significantly associated with QUANTIDD (β = 99.9 ± 11.4, p < 0.001) in the single regression model and in the multiple regression model controlled for covariates (β = 36.4 ± 11.3, p = 0.002). Longitudinal analysis showed that HALE increased with QUANTIDD during the 15-year study period (β = 46.4 ± 5.1, p < 0.001), and this association was also significant when controlled for covariates (β = 39.7 ± 5.1, p < 0.001). Longitudinal association of QUANTIDD with the percentage difference between life expectancy and HALE controlled for covariates was significantly negative (β = - 1.3 ± 0.5, p = 0.011).

Conclusions: After controlling for socioeconomic indicators, longer healthy life is enjoyed by populations of countries with greater dietary diversity.