Association of the dietary phytochemical index with circadian rhythm and mental health in overweight and obese women: A cross-sectional study

Clin Nutr ESPEN. 2022 Apr:48:393-400. doi: 10.1016/j.clnesp.2022.01.012. Epub 2022 Jan 19.


Background: Previous studies showed that some dietary indexes are the most important reasons to increase the incidence and spread of mental health disorders and circadian rhythm. We aimed to assess the association between the phytochemical index with circadian rhythm and mental health disorders in obese and overweight women.

Methods: Participants were selected from different health centers by a multistage cluster random sampling method. Dietary intake was assessed by a semi-quantitative food frequency questionnaire (FFQ) with 147 items. Dietary phytochemical index (DPI) was estimated using the following formula: (daily energy derived from phytochemical-rich foods (kcal)/total daily energy intake (kcal)) × 100. Symptoms of mental health disorders were assessed using a validated depression, anxiety, stress scales (DASS) questionnaire with 21-items. The Circadian rhythm was assessed by the morningness-eveningness questionnaire (MEQ).

Results: The mean age and BMI of our participants were 35.19 and 30.48, kg/m2 respectively. After controlling for potential confounders, women in the highest tertile of phytochemical index (PI) had a lower prevalence of depression (P = 0.023) and would be rarely morning type (OR = 1.044, 95% CI 1-1.090) compared with those in the lowest tertile of the PI. In contrast, there was no association between PI and anxiety (OR = 1.001, 95% CI 0.945-1.060) and stress (OR = 0.992, 95% CI 0.940-1.046).

Conclusion: We found that high adherence to PI can decrease depression and increase MEQ score. Moreover, there was a relationship between adherence to PI and circadian rhythm. However, there was no association between a high level of PI and other mental problems.

Keywords: Circadian rhythm; Mental health; Morningness-eveningness questionnaire; Phytochemical index.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Circadian Rhythm
  • Cross-Sectional Studies
  • Female
  • Humans
  • Mental Health*
  • Obesity / complications
  • Obesity / epidemiology
  • Overweight*
  • Phytochemicals


  • Phytochemicals