Associations of protein-enriched dietary diversity, anti-inflammatory dietary diversity, and low muscle mass among older Chinese adults: a nationwide cross-sectional analysis

Low muscle mass (LMM) is a common health problem among older adults and has been closely linked to functional decline and adverse health outcomes. Dietary diversity has been identified as an important determinant of muscle health. Nevertheless, no systematic research has clarified the parallel associations of protein-rich dietary diversity and anti-inflammatory dietary diversity with LMM. This study utilized cross-sectional data from 12,986 individuals aged ≥ 65 from the 2018 China Longitudinal Healthy Longevity Survey (CLHLS). Drawing on previous studies, dietary diversity was assessed based on the consumption frequency of nine food groups collected through face-to-face interviews, from which the dietary diversity index (DDI), the protein-enriched dietary diversity index (PEDDI), and the anti-inflammatory dietary diversity index (AIDDI) were constructed. We employed a validated anthropometric prediction equation to estimate appendicular skeletal muscle mass (ASM) in Chinese older adults and subsequently evaluate low muscle mass (LMM). Multivariable logistic regression models were applied to evaluate the associations, with statistical adjustment for a range of potential confounders. In the fully adjusted model, we found that higher dietary diversity indices (DDI, PEDDI, and AIDDI) were inversely associated with the prevalence of LMM. Specifically, each 1-unit increase in DDI, PEDDI, and AIDDI scores was associated with 8% (OR = 0.92, 95% CI: 0.89–0.95), 6% (OR = 0.94, 95% CI: 0.91–0.98), and 13% (OR = 0.87, 95% CI: 0.82–0.91) lower odds of LMM, respectively. Subgroup analyses were conducted to evaluate potential interaction effects, revealing stronger inverse associations observed in women (P < 0.001). Our findings suggest that greater dietary diversity, particularly protein-rich and anti-inflammatory foods, is associated with a lower prevalence of LMM among older adults in this cross-sectional study. This underscores the potential importance of dietary diversity as a modifiable factor for promoting healthy aging.