Association of proinflammatory diet with low-grade inflammation: results from the Moli-sani study

Objectives: The association between diet and inflammation is well documented. Yet, no evidence exists on the relationship between the inflammatory potential of the diet and low-grade inflammation (LGI) as measured by a composite score of plasma and cellular biomarkers. The aim of this study was to assess the association between the Dietary Inflammatory Index (DII^®) and LGI in a large population-based cohort.

Methods: Cross-sectional analyses were conducted on data from 20 823 adults (age ≥35 y; 48% male) without acute inflammation, who were recruited within the general population of the Moli-sani study from 2005 to 2010. LGI was measured by using a composite score (INFLA-score) including platelet and leukocyte counts, the granulocyte to lymphocyte ratio, and C-reactive protein. DII scores were computed based on dietary intake assessed by the EPIC food frequency questionnaire. Multivariable linear regression models were fit to produce adjusted regression coefficients and 95% confidence intervals (CIs).

Results: Higher DII scores were associated with increased LGI (β = 0.131; 95% CI, 0.089-0.174 for the highest versus lowest quintile of DII) after adjusting for age, sex, lifestyle, prevalence of chronic diseases, and health conditions. A higher DII score also was positively associated with each single biomarker of inflammation included in the INFLA-score, unhealthy behaviors (smoking, sedentary lifestyle), and insulin.

Conclusions: Higher DII scores, indicating greater inflammatory potential of the diet, were directly associated with LGI, as measured by a composite score of plasma and cellular biomarkers of inflammation. These findings are consistent with the contributing role of diet-mediated inflammation in increasing risk for inflammation-related chronic diseases.