Dietary acid load and oxidative stress in relation to sleep quality and duration among Iranian adults

Few studies assessed the relation between dietary acid load and sleep quality and duration in Middle Eastern populations. Moreover, no study evaluated the potential relationship between oxidative stress biomarkers and sleep parameters. We conducted the present cross-sectional investigation to comprehensively assess this issue. Dietary acid load was assessed using a validated semi-quantitative 168-item food frequency questionnaire. Oxidative stress biomarkers were evaluated in participants' blood samples after a 12-h fast. Sleep quality and duration were assessed using the validated Pittsburgh Sleep Quality Index (PSQI). A total of 536 Iranian adults (289 men) with a mean age of 42.59 year were included. Participants in the second and third tertiles of potential renal acid load (PRAL) ([OR_{T2 vs. T1}=1.79; 95%CI: 1.03-3.15], [OR_{T3 vs. T1}=2.47; 95%CI: 1.44-4.32]) and net endogenous acid production (NEAP) ([OR_{T2 vs. T1}=2.07; 95%CI: 1.20-3.61], [OR_{T3 vs. T1}=2.58; 95%CI: 1.49-4.53]) were more likely to have short sleep duration, compared to the reference. Moreover, participants in the third tertile of PRAL (OR_{T3 vs. T1}=1.72; 95%CI: 1.02-2.90), and NEAP (OR_{T3 vs. T1}=1.77; 95%CI: 1.05-3.00) were more likely to have poor-quality sleep than those in the first tertile. Higher malondialdehyde levels (MDA > 185 nmol/mL) and lower glutathione peroxidase (GPx < 0.70 mU/mL) were associated with higher odds of poor sleep quality. All mentioned results were based on fully adjusted model. In conclusion, there was a dose-related direct association between dietary acid load and odds of disrupted sleep quality and duration, especially in overweight/obese adults. Higher oxidative stress levels (higher MDA and lower GPx) were non-linearly associated with higher odds of poor sleep quality.