Cardiorespiratory fitness is positively associated with both healthy and western dietary pattern in Iranian middle-aged.

Background : The association between dietary patterns and cardiorespiratory fitness (CRF) is not well established. Objective : We sought to investigate association between a posteriori dietary pattern and CRF in middle-aged adults. Design : Adults (n = 276), aged 20-74 years, who were residents of Tehran, Iran were recruited. Diet was assessed by using a validated 168-item semi-quantitative food frequency questionnaire. Principal component analysis was used to derive dietary patterns. Socio-economic status, anthropometric measures, body composition, and blood pressure were recorded. CRF was assessed by using a graded exercise treadmill test. Analysis of variance and linear regression models were used to discern the association between dietary patterns and CRF. Results : Higher scores of the healthy dietary pattern had no association with VO _2max (p = 0.13 ). After controlling for potential confounders, VO _2max was positively associated across tertiles of healthy dietary patterns (p < 0.001). Higher adherence to the "mixed" dietary pattern was inversely related to VO _2max (p < 0.01). After adjusting for confounders, the significant association disappeared (p = 0.14). Higher scores of the "Western" dietary pattern was not associated with VO _2max (p = 0.06). However, after controlling for potential confounders, VO _2max was positively associated with the "Western" dietary pattern (p = 0.01). A positive linear association between the "healthy" dietary pattern and CRF for the total sample (R ²  = 0.02; p < 0.01) were presented. Conclusions : Overall, our findings suggest that higher adherence to a "healthy" and "Western" dietary pattern was positively associated with CRF. However, further studies are required to examine and clarify the causal relationship between dietary patterns and CRF.