Table 6.

Assessment of dietary intake and serum vitamin D levels and prevalence of depressive symptoms.

Authors	Year of Publication	Type of Study	The Group	Assessment of Depression and Dietary Intake	Results and Conclusions
Vitamin D
Pooyan et al. [58]	2018	Cross-sectional study	n = 265 adults	Depression Anxiety Stress Scales 21 (DASS-21) and Semi-quantitative Food Frequency Questionnaire (FFQ)	In healthy adults without chronic disease, a high-protein/low-fat diet may interact with the genotype of vitamin D-binding protein VDBP to reduce the risk of depression.
Jahrami et al. [118]	2020	Clinical-control study	n = 192 participants: 96 patients with depression and 96 age- and sex-matched controls	Beck Depression Inventory-II (BDI-II) and Food Frequency Questionnaire (FFQ) (covering 102 foods distributed on 38 items/groups)	Depressed patients have significantly lower serum vitamin D levels. Depressed patients appeared to have statistically significantly less vitamin D from sunlight sources, even though dietary vitamin D intake was the same in both groups. Approximately 80% of depressed patients and 70% of controls have been shown not to take adequate daily doses of vitamin D.