Dietary inflammatory potential: a comprehensive approach to the inclusion of flavonoids

Abstract The Dietary Inflammatory Index (DII) has been widely used to estimate dietary inflammation. However, most studies do not consider the six classes of flavonoids (6F) included in the original DII. This study aimed to develop two new tools, the Complete-DIP (CDIP) and Short-DIP (SDIP), to estimate the Energy-adjusted Dietary Inflammatory Potential (DIP) in adults while exploring the benefit of including the 6F. An open-access reference population (RP) was created from the Global Dietary Database (GDD) to calculate DIP. CDIP considered 38 food parameters (FP), whereas SDIP excluded the 6F and considered 32 FP. CDIP and SDIP were estimated for 3501 participants aged 18-84 from the IAN-AF. FP intake z-scores were calculated using FPs from the RP. Centred percentiles were multiplied by the FP’s inflammatory effects (IE) to obtain FP-specific DIP, which were then summed to achieve the individual DIP. IE were retrieved from the literature. Lower DIP values indicated more anti-inflammatory diets. Linear regressions assessed the association between sociodemographic factors and diet quality (measured with the Healthy Eating Index (HEI)) with DIP. Pearson’s test evaluated the correlation between CDIP and SDIP. The mean and standard deviation for CDIP and SDIP were 0.00±2.17 and 0.02±1.74, respectively. Men had more pro-inflammatory diets than women using CDIP (β = 0.354[95%CI:0.209,0.499]), but this effect was not statistically significant when using the SDIP. Older adults had more anti-inflammatory diets than adults (CDIP: β=-0.668[95%CI:-0.850,-0.486]; SDIP: β=-0.548[95%CI:-0.529,-0.076]). Participants with lower diet quality (Q1 of HEI vs Q4) had higher DIP (CDIP: β = 2.309[95%CI:2.116,2.502]; SDIP: β = 2.185[95%CI:2.037,2.334]). A very strong correlation between the CDIP and the SDIP was observed (r = 0.94). Results suggest that CDIP and SDIP may be equally successful in estimating dietary inflammation. However, the advantage of adding the 6F to evaluate the DIP needs further research. Key messages • This study created two open-access energy-adjusted dietary inflammatory potentials (DIP), with and without flavonoids. • Results suggest that flavonoids may not be essential for accurate DIP estimations.