A new dietary inflammatory index predicts interval changes in serum high-sensitivity C-reactive protein

Abstract

Inflammation is associated with a number of chronic conditions, such as cancer and cardiovascular disease. Reducing inflammation may help prevent or treat these conditions. Diet has consistently been shown to modulate inflammation. To facilitate research into the inflammatory effect of diet on health in humans, we sought to develop and validate an Inflammatory Index designed to assess the inflammatory potential of individuals' diets. An Inflammatory Index was developed based on the results of an extensive literature search. Using data from a longitudinal observational study that carefully measured diet and the inflammatory marker, serum high-sensitivity (hs) C-reactive protein (CRP), in approximately 600 adults for 1 y, we conducted analyses to test the effect of Inflammatory Index score on hs-CRP as a continuous and dichotomous (<or=3 mg/L, >3 mg/L) indicator of inflammatory response, while controlling for important potential confounders. Results based on continuous measures of hs-CRP suggested that an increasing Inflammatory Index score (representing movement toward an antiinflammatory diet) was associated with a decrease in hs-CRP. Analyses using hs-CRP as a dichotomous variable showed that an antiinflammatory diet was associated with a decrease in the odds of an elevated hs-CRP (P = 0.049). The results are consistent with the ability of the Inflammatory Index to predict hs-CRP and provide additional evidence that diet plays a role in the regulation of inflammation, even after careful control of a wide variety of potential confounders.

FIGURE 1

Example of how weighting was carried out for each food and constituent in the development of the Inflammatory Index. Saturated fat had a total of 15 articles, which resulted in 88 weighted. In step 1, articles were multiplied by assigned weights (Table 1). The total antiinflammatory and proinflammatory weight was divided by the total weight for saturated fat. In step 2, the proinflammatory fraction was subtracted from the antiinflammatory fraction.