Development of an Inflammatory Food Index and Association with Inflammatory Markers and Diabetes—Longitudinal Study of Adult Health (ELSA-Brasil)

Introduction: Diet plays a central role in the regulation of inflammation and is closely related to the development of chronic diseases. Dietary patterns portray eating habits more comprehensively than nutrients or foods alone, and provide better understanding and predictive power in relation to causal processes. The objective was to develop an Index of Food Inflammation (IFI) derived from Reduced Rank Regression (RRR) based on its relation with inflammatory markers in the ELSA-Brasil population, and to evaluate its association with weight gain and incidence of diabetes.

Methods: Food consumption data were obtained from a food frequency questionnaire of 9778 participants, after exclusions. The RRR methodology initially involved 42 food groups. Spearman’s correlation coefficients were used to evaluate the associations between quantitative variables, and, for the IFI, linear regression to evaluate its association with weight gain, logistic regression with large gains, and Cox regression with incident diabetes.

Results: The inflammatory dietary pattern was composed of 17 pro-inflammatory food groups, including processed or red meat, pork, sugary soft drinks, and hotdogs, and seven anti-inflammatory groups, notably fruits, nuts and wine. The IFI was associated with weight gain, risk of a large weight gain (quartile 4 vs. 1: adjusted OR=1.42; 95% CI 1.15-1.76) and risk of developing diabetes (quartile 4 vs. 1: adjusted HR=1.29; 95% CI 1.01-1.65).

Conclusion: The associations, although small, suggest that subclinical inflammation could be one of the ways by which diet causes certain chronic diseases. Ultra-processing of foods could be an important determinant in the pro-inflammatory aspect of some current dietary patterns.