Association between dietary inflammatory index and psychological profile in adults

Background & aims: Limited data are available on the association of inflammatory potential of the diet and odds of psychological disorders. We investigated the association between adherence to a pro-inflammatory diet, as measured by Dietary Inflammatory Index (DII), and odds of psychological disorders.

Methods: In this cross-sectional study, dietary intakes of 3363 Iranian adult participants were collected using a validated Dish-based 106-item Semi-quantitative Food Frequency Questionnaire (DS-FFQ). DII score was calculated based on participants' dietary intakes obtained from DS-FFQ. The Iranian validated version of Hospital Anxiety and Depression Scale (HADS) and General Health Questionnaire (GHQ) was used to assess psychological disorders. For depression and anxiety, scores of 8 or more on either subscale were considered as psychological disorders and scores of 0-7 were defined as "normal". In terms of psychological distress, the score of 4 or more was defined as psychological distress.

Results: Overall, 28% (n = 943) of study participants had depression, 13.3% (n = 448) were affected by anxiety and 22.6% (n = 760) by psychological distress. After controlling for potential confounders, individuals in the highest quintile of DII score had higher scores of depression (6.56 ± 0.16 vs. 5.48 ± 0.16; P < 0.001), anxiety (3.85 ± 0.17 vs. 3.09 ± 0.17; P = 0.006), and psychological distress (2.42 ± 0.13 vs. 1.77 ± 0.13; P = 0.001), compared with those in the lowest quintile. Participants in the top quintile of DII score had greater odds of depression (OR: 1.84, 95% CI: 1.30-2.60), anxiety (OR: 1.69, 95% CI: 1.07-2.67), and psychological distress (OR: 1.72, 95% CI: 1.20-2.46) than those in the bottom quintile.

Conclusions: We found that adherence to a pro-inflammatory diet was positively associated with psychological disorders.