[Development and validation of the nutrient-rich food index for China]

Objective: To select the nutrient-rich food(NRF) index applicable to the food characteristics of Chinese residents through population-based dietary quality validation.

Methods: Sixteen NRF indices were constructed based on the Chinese Food Composition Table and the Chinese Food Labelling Nutrient Reference Values, using 100 g as the base amount of food for calculation. The NRF indices were validated by the China Prime Diet Quality Score(CPDQS), a dietary quality assessment index, using food intake data collected from 14 068 adult residents in 15 provinces in 2018 under the China Health and Nutrition Survey. The CPDQS was used as the dependent variable and the dietary NRF index score was used as the independent variable. The multiple linear regression models were performed after adjusting the covariates and the NRF index with the largest coefficient of determination R~2 was used as the most appropriate index.

Results: Regression analysis showed that the R~2 of NRF8.2 index was the largest, which was 0.16. Dried legumes, fungi and algae, nuts, vegetables, eggs and aquatic products scored higher on the NRF8.2 index. The high scoring subgroups had higher average daily intakes of cereals and potatoes, vegetables, fruits, soybeans and nuts, dairy, eggs and aquatic products, as well as lower consumption of livestock and poultry meat, beverages, salt and cooking oil, compared to the low scoring subgroup on the Dietary NRF8.2 Index. In terms of nutrient intake, the medium and high NRF8.2 subgroups had relatively high intakes of energy, protein, vitamins and minerals and relatively low intakes of fat and sodium.

Conclusion: The NRF8.2 index explains the maximum variation in CPDQS and is a relatively suitable NRF index for the Chinese population.