Extra-virgin olive oil improves depression symptoms without affecting salivary cortisol and brain-derived neurotrophic factor in patients with major depression: a double-blind randomized controlled trial
Abstract
BACKGROUND
Many patients with depression are reluctant to take psychiatric medications. Hence, complementary therapies such as nutritional considerations could be advantageous. The antidepressant potential of olive oil has been proved in observational studies.
OBJECTIVE
The effect of extra-virgin olive oil (EVOO) on depression symptoms and cortisol and brain-derived neurotrophic factor (BDNF) levels in patients with depression was examined.
DESIGN AND PARTICIPANTS
This was a double-blind randomized controlled trial conducted on 73 patients suffering from major depressive disorder in Shiraz, Iran, in 2016.
INTERVENTION
The patients were randomly assigned to intervention (EVOO) and control (sunflower oil) groups and consumed 25 ml/day of the corresponding oil for 52 days.
MAIN OUTCOME MEASURES
Depression symptoms were assessed by Beck Depression Inventory-II (BDI-II) and 7-item Hamilton Depression Rating Scale (HAMD-7). Salivary cortisol levels were determined immediately after awakening (T0) and 30 minutes later (T30). Cortisol awakening response (CAR) and the area under the curve with respect to ground (AUCG) and increase (AUCI) were computed. Serum BDNF concentrations were also measured.
STATISTICAL ANALYSES PERFORMED
Statistical analysis was conducted based on intention-to-treat (ITT) and per-protocol (PP) approaches. Within-group changes were examined with repeated measures (for BDI-II and HAMD-7) and with paired t-test (for other variables). Between-group comparisons…
How strong is the evidence?
Evidence Hub reads this as a randomized trial, done in people. Its evidence level is 2 of 5 (High · randomized trial). Randomized trials of a reasonable size are the strongest single-study design. Reported size: 73 participants or records.
Read the paper
Related studies
- Cortisol, obesity and the metabolic syndrome: A cross-sectional study of obese subjects and review of the literature
- Relationships between lead biomarkers and diurnal salivary cortisol indices in pregnant women from Mexico City: a cross-sectional study
- Pubertal Recalibration of Cortisol Reactivity Following Early Life Stress: A Cross-Sectional Analysis
- High-end normal adrenocorticotropic hormone and cortisol levels are associated with specific cardiovascular risk factors in pediatric obesity: a cross-sectional study
- Effects of remote virtual work environment during COVID-19 pandemic on technostress among Menoufia University Staff, Egypt: a cross-sectional study
- Low serum albumin, aspartate aminotransferase, and body mass are risk factors for frailty in elderly people with diabetes–a cross-sectional study
Go deeper in Evidence Hub
Evidence Hub adds a study data sheet (design, sample size, evidence level, key numbers), an AI summary and a chat grounded in the paper's text.