Higher dietary diversity and better healthy aging: A 4-year study of community-dwelling middle-aged and older adults from the Taiwan Longitudinal Study of Aging

Objectives: To investigate the relationship between dietary diversity and healthy aging (in terms of mobility performance, physical functions, cognitive functions, and depressive symptoms) among community-dwelling middle-aged and older adults by using a nationally representative population-based cohort study.Methods: Data from 3213 study participants in the Taiwan Longitudinal Study on Aging (TLSA) were retrieved for analysis, and all participants were divided into five groups according to the quintile of dietary variety scores (DVSs). In the 4-year follow-up study, multivariate logistic regression models were applied to investigate the associations between DVS subgroups and declines in mobility performance, physical function (activities of daily living (ADLs) and instrumental activities of daily living (IADLs)), cognitive function and depressive symptoms.Results: In this study, the DVS quintile identified people who were significantly vulnerable in diet quality. Among those in the lowest DVS quintile, the proportions consuming seafood, eggs, and beans/legumes per week were 0.3 %, 7.8 % and 12.6 %, respectively, while among those in the highest DVS quintile, the proportions were 40.2 %, 83.1 %, and 82.7 %, respectively. "Inverse" dose-response associations were observed between the DVS and the risks of decline in mobility performance, physical function (ADLs and IADLs), cognitive function, and depressive symptoms. These risks decreased with the higher DVS quintile group as compared to the lowest DVS quintile group. Even after adjustments for demographics, health behaviors (e.g., physical activity) and comorbidities, participants in the highest DVS quintile group were still associated with the lowest risk of decline in ADLs (adjusted odds ratio (aOR) 0.59 [95 % confidence interval (CI) 0.37-0.94], p < 0.05) and IADLs (aOR 0.53 [0.39-0.73], p < 0.01). However, no such association was observed in the risk of worsened mobility performance, cognitive function and depressive symptoms.Conclusions: In conclusion, higher dietary diversity has protective effects in declines in multidimensional outcomes associated with healthy aging, particularly physical functions (ADL and IADL), among communitydwelling middle-aged and older adults. Intervention studies are needed to confirm the causal relationships between dietary diversity and healthy aging.