Dietary acid load in relation to depression and anxiety in adults

No previous study has examined the association of dietary acid load (DAL) with depression and anxiety in adults. The present study aimed to investigate the association between DAL and the risk of depression and anxiety in Iranian adults.

In total, 4378 non-academic healthy personnel (1909 men and 2469 women) were included in this cross-sectional study. A validated detailed food frequency questionnaire (FFQ) was used to assess dietary intakes of participants. DAL was estimated using the protein to potassium ratio (Pro:K). Depression and anxiety were screened using an Iranian validated Hospital Anxiety and Depression Scale questionnaire.

Participants with the highest DAL had a higher risk of depression compared to those in the lowest category [odds ratio (OR) = 1.57; 95% confidence interval (CI) = 1.27-1.95, P_trend  < 0.001), which remained unchanged after controlling for probable confounders, such that those in the top category of DAL had a 100% higher risk of having depression than those in the bottom category (OR = 2.00; 95% CI = 1.52-2.64). In addition, a significant positive association was seen between DAL and anxiety in a crude model (OR = 1.35; 95% CI = 1.02-1.78, P_trend  = 0.01) and even after adjustment for a wide range of confounders, such that participants in the top category of DAL had a 92% greater risk of anxiety than those in the bottom category (OR = 1.92; 95% CI = 1.35-2.74, P_trend  < 0.001).

In the present study, we found a significant direct association between DAL and the risk of depression, as well as anxiety. Further studies, in particular prospective cohorts are required to confirm these findings.