Table 2.

Relationship between dietary macronutrients and water intake and the risk of depressive symptoms.

Authors	Year of Publication	Type of Study	The Group	Assessment of Depression and Dietary Intake	Results and Conclusions
Proteins
Li et al. [47]	2020	National cross-sectional survey	n = 17,845 adults	Patient Health Questionnaire-9 (PHQ-9) and two 24 h dietary recall interviews	Total protein intake and protein intake from milk and dairy products may reduce the risk of depressive symptoms in American adults, but not for protein intake from red meat, poultry, fish, cereals, and legumes.
Sheikhi et al. [48]	2023	Cross-sectional study	n = 489 Iranian women	Depression, Anxiety, and Stress Scales (DASS) questionnaire and Semi-quantitative Food Frequency Questionnaire	Women were more likely to show symptoms of depression in the highest tertile of animal protein intake. A diet high in animal protein may predispose to mental illness.
Amino acids
Suga et al. [49]	2018	Cross-sectional study	n = 7923 adults	Center for Epidemiologic Studies Depression Scale (CES-D) and validated, self-administered diet history questionnaire	Women with depression consumed more energy and less tryptophan than women without depression. Tryptophan intake was inversely associated with depressive symptoms in young adult women.
Koochakpoor et al. [50]	2021	Cross-sectional study	n = 3175 adults	Hospital Anxiety and Depression Scale (HADS) and Food Frequency Questionnaire (FFQ)	Subjects in the study with the highest total branched-chain amino acid (BCAA) tercile intake had a lower risk of depression. There was also a significant inverse relationship observed between isoleucine intake and the likelihood of depression.
Reuter et al. [51]	2021	Cross-sectional study	n = 482 adults	Beck Depression Inventory-II (BDI-II) and participants were asked for their general consumption of TRP-rich foods	A diet rich in tryptophan has been shown to have a positive effect on mood. High amounts of tryptophan in the diet appear to protect against depression and have a positive effect on social interactions.
Fats
Wilson et al. [52]	2021	Cross-sectional study	n = 887 adults	Beck Depression Inventory-II (BDI-II) and Dietary Instrument for Nutrition Education questionnaire (DINE)	No relationship was observed between the amount of fat ingested in the diet and mental health.
Currenti et al. [53]	2023	Cross-sectional study	n = 1572 adults	Center for the Epidemiological Studies of Depression Short Form (CES-D and two Food Frequency Questionnaires (FFQs; a long and a short version)	No association was found between total fat intake and depressive symptoms.
Carbohydrates
Sanchez-Villegas et al. [54]	2018	Prospective cohort study	n = 15,546 adults	Follow-up questionnaire and diagnosis of depression using a clinical interview for DSM-IV and Semi-quantitative FFQ	Greater exposure to added sugars and low-quality carbohydrates correlate with a higher risk of depression.
Ebrahimpour-Koujan et al. [55]	2019	Cross-sectional study	n = 3362 adults	Hospital Anxiety and Depression Scale and General Health Questionnaire-12 and Semi-quantitative Food Frequency Questionnaire	Depression was not associated with adherence to a low-carbohydrate diet.
Makhani et al. [56]	2021	Cross-sectional study	n = 9728 adults	Patient Health Questionnaire-9 (PHQ-9) and two 24 h dietary recall interviews	The higher the ratio of carbohydrate-to-fibre intake in the diet, the higher the risk of depressive symptoms, which can be moderate to severe in severity.
Amirinejad et al. [57]	2022	Cross-sectional study	n = 7384 adults	Depression Anxiety Stress Scales and Validated Food Frequency Questionnaire	No significant association was observed between the dietary glycaemic index (DGI) and glycaemic load (DGL) and the likelihood of depression.
Total macronutrients
Pooyan et al. [58]	2018	Cross-sectional study	n = 265 adults	Depression Anxiety Stress Scales 21 (DASS-21) and Semi-quantitative Food Frequency Questionnaire and blood samples were taken, and biochemical measurements were taken	A significant interaction was found between the high-protein and low-fat diets and the low-fat diet and the rs7041 polymorphism in groups with moderate and severe depression. In healthy adults without chronic diseases, a high-protein, low-fat diet may interact with the VDBP genotype to reduce the risk of depression.
Oh et al. [59]	2020	Cross-sectional study	n = 76,635 (60,935 from the United States and 15,700 from South Korea)	Patient Health Questionnaire-9 (PHQ-9) and 24 h dietary recall interview	In both the United States and South Korea, people with low protein intake had a significantly higher risk of depression than those with normal protein intake. When the proportion of kilocalories consumed from protein increased by 10%, the prevalence of depression was significantly reduced. There was no significant association between fat intake and depression in either country. An association was observed between carbohydrate intake and the incidence of depression in the United States, but not in South Korea.
Eissenstat et al. [60]	2020	Cross-sectional study	n = 4747 adults	Patient Health Questionnaire-9 (PHQ-9) and two 24 h dietary recall interviews	For respondents of Hispanic origin, total protein intake and fats were negatively associated with depressive symptoms. In Caucasians, the intake of dietary fibre was negatively associated with symptoms of depression.
Lee et al. [61]	2021	Cross-sectional study	n = 6336 adults (3102 Korean adults and 3234 Americans)	Patient Health Questionnaire-9 (PHQ-9) and 24 h dietary recall interview	A low intake of protein and dietary fibre as a result of food insecurity can increase the risk of depression. Adequate diet and food security can play an important role in the prevention of depression.
Water
Haghighatdoost et al. [62]	2018	Cross-sectional study	n = 3327 adults	Hospital Anxiety and Depression Scale and water consumption was assessed by asking about the number of glasses of water that were consumed daily (<2, 2–5, and ≥5 glasses of water/day)	A significant inverse relationship was shown between water consumption and depression. Drinking <2 glasses of water per day was associated with a 73% increased risk of depression in men and 54% in women.