Association between plant-based dietary indices, the dietary inflammatory index and inflammatory potential in female college students in Saudi Arabia: a cross-sectional study.

ABSTRACT Background Saudi Arabian diets are transitioning to more “Western” dietary patterns which have been associated with higher levels of inflammation. Emerging evidence suggests plant-based diets are related to lower levels of inflammation, however, the definition of plant-based diets varies. Objective The purpose of this study was to identify the extent to which an overall plant-based diet index (PDI), healthy-PDI (hPDI), and unhealthy-PDI (uPDI) versus energy-adjusted dietary inflammatory index (E-DII) correlate with high-sensitivity C-reactive protein (hs-CRP). Design This was a cross-sectional study carried out at King Saud University. Data on dietary intake, anthropometrics, and hs-CRP were collected. Participants/setting Female students aged 19–35 (n=401) were recruited from King Saud University, Riyadh, Saudi Arabia between February and May 2019. Main outcome measures The main outcome was hs-CRP. Statistical analyses performed Pearson correlation and multivariate linear regression analyses were used to examine the associations between hs-CRP, each PDI, and E-DII. Results E-DII and uPDI scores had a moderate and a small positive correlation with hs-CRP levels (r=0.46 and 0.22, respectively), while PDI and hPDI scores had a small and a moderate inverse correlation with hs-CRP levels (r=-0.13 and -0.31, respectively). A 1-SD higher E-DII score was directly associated with a 1.05 mg/l higher hs-CRP (95% confidence interval (CI): 0.72, 1.38, p Conclusions While all indices had a small or moderate correlation with hs-CRP, only E-DII score was positively associated with hs-CRP. Future research can examine PDI-based interventions for lowering inflammation.