association of dietary acid-base load with psychological disorders, sleep and circadian rhythm among obese and overweight women: a cross-sectional study

Background: Epidemiological studies have reported that dietary acid load is associated with psychological disorders through different pathways. We aimed to examine the association of dietary acid-base load with psychological disorders, sleep and circadian rhythm. Methods: This study was performed on 404 female subjects aged 18 years and above. We evaluated potential renal acid load (PRAL) and net endogenous acid production (NEAP) score by a validated food frequency questionnaire (FFQ) for Iran which contained 147 items. To assess psychological disorders, an Iranian validated version of the depression, anxiety and stress scale (DASS-21) was used. The Pittsburgh Sleep Quality Index (PSQI) and morning-evening questionnaire (MEQ) were applied to evaluate sleep quality and circadian rhythm status, respectively. Results: After adjustment for a wide range of confounding variables, a significant positive association was observed between dietary acid-base load and severe depression (ORPRAL=1.10, 95% CI=1.01-1.19, p=0.02 and ORNEAP=2.46, 95% CI=1.41-14.61, p=0.02). Women in the high dietary acid base load category had higher anxiety (ORPRAL=1.12, 95% CI=1.02-1.23, p=0.01 and ORNEAP=1.80,95% CI=1.12-10.72, p=0.01). There was a strong positive relationship between dietary acid-base load and sleep disturbance (p<0.05). Additionally, circadian rhythm assessment showed that those with greater commitment to PRAL had 23% higher risk of being completely evening type, while the odds of being completely morning type were decreased by 15% and 12% across higher adherence to PRAL and NEAP. Conclusion: Women with higher dietary acid-base load score had greater odds for depression, anxiety, psychological distress, sleep disturbance and evening-type circadian rhythm compared to lower ones.