Understanding dietary and staple food transitions in China from multiple scales

China is facing both non-communicable diseases (NCDs) and micronutrient deficiency, which have been largely related to transitions within Chinese diets, for example, the overconsumption of vegetable oils and animal-source products and decreasing consumption of coarse staple foods. In this study, we use three metrics—dietary diversity score (DDS), staple diversity score (SDS) and the proportion of coarse staple consumption (PoCS)- to investigate overall dietary transitions as well as trends in staple food consumption for nine provinces in China from 1997 to 2009. We also investigated how household characteristics, community urbanicity, and provincial conditions have affected household diets and the relationship between overall diet and staple diet across socio-economic gradients. Overall dietary diversity (DDS) showed consistent growth across all the provinces and subpopulations and was strongly associated with a household’s socio-economic status. However, staple indicators (SDS and PoCS) showed notable difference both geographically and socio-economically. The relationship between overall dietary indicator (DDS) and staple indicators (SDS, PoCS) across SES gradients revealed that education is a more important influence than income in ensuring dietary balance and nutritional quality. Our findings show that programs aimed at promoting dietary balance and healthy staple diets must account for differences between provinces in terms of agronomic, nutritional, social, and economic conditions. By identifying the socio-economic characteristics and locations of the most nutritionally vulnerable populations, this study also points toward the need for policies that incorporate nutritional considerations into grain production systems and provide a strategy for enhancing China’s national food security.

中国同时面临非传染性疾病（non-communicable diseases, NCDs）与微量营养素缺乏问题，此类问题在很大程度上与中国居民膳食结构转型相关，例如植物油及动物源食品摄入过量、粗粮主食消费量下降。本研究采用膳食多样性评分（dietary diversity score, DDS）、主食多样性评分（staple diversity score, SDS）以及粗粮主食消费占比（proportion of coarse staple consumption, PoCS）三项指标，针对1997至2009年中国9个省份的居民整体膳食转型情况与主食消费趋势展开调研。本研究同时探究了家庭特征、社区城市化水平以及省级层面的环境条件如何影响家庭膳食结构，以及整体膳食与主食膳食在社会经济梯度下的关联。整体膳食多样性（DDS）在所有省份及亚人群中均呈现持续增长态势，且与家庭社会经济地位显著相关。然而，主食相关指标（SDS与PoCS）在地理分布与社会经济层面均表现出显著差异。针对社会经济梯度下整体膳食指标（DDS）与主食指标（SDS、PoCS）之间的关联分析显示，在保障膳食平衡与营养品质方面，教育水平的影响程度高于收入。研究结果表明，旨在推广膳食平衡与健康主食膳食的相关政策，必须考虑不同省份在农艺、营养、社会与经济条件方面的差异。本研究通过识别营养脆弱程度最高的人群的社会经济特征与地域分布，同时指出需出台将营养考量纳入粮食生产体系的相关政策，并为提升中国国家粮食安全提供了可行策略。