Associations Between Mediterranean Diet, Processed Food Consumption, and Symptoms of Anxiety and Depression: Cross-Sectional Study Among Israeli Adults

Abstract

Introduction: Mental health disorders, particularly anxiety and depression, contribute significantly to the global disease burden. Growing evidence suggests that dietary patterns play a crucial role in mental health outcomes. Objectives: This cross-sectional study examines the associations between adherence to a Mediterranean diet, processed food consumption, and symptoms of anxiety and depression among Israeli adults. Additionally, it investigates whether sleep quality mediates these relationships. Methods: A total of 303 participants completed an online survey assessing demographic variables, health-related behaviors, dietary patterns, sleep quality and duration, and mental health indicators. Results: Pearson correlations revealed significant associations between dietary patterns and mental health symptoms. Higher Mediterranean diet adherence was associated with lower anxiety and depression scores, whereas greater processed food consumption was linked to increased psychological distress. Hierarchical regression analyses showed that dietary patterns significantly predicted anxiety and depression symptoms, even after controlling for demographic and health-related factors. However, sleep quality did not mediate these relationships, suggesting independent effects of diet and sleep on mental health. Conclusions: These findings highlight the potential of dietary modifications as a complementary approach to mental health management, though generalizability is limited by our predominantly female, Jewish Israeli sample studied during a period of conflict. Integrating nutritional assessments into mental health care could enhance treatment strategies. Future research should explore longitudinal and interventional approaches to establish causal relationships between diet quality and mental health outcomes. This study highlights the clinical and public health relevance of dietary assessment in mental health evaluations and supports the development of integrated, nutrition-informed interventions to enhance psychological well-being.

1. Introduction

Depression and anxiety affect millions globally, with major depressive disorder (MDD) having a global prevalence of 332 million cases in 2021, with an age-standardized prevalence rate of 4006.8 per 100,000 population [1], and anxiety disorders affecting approximately 359 million people worldwide, with an age-standardized prevalence rate of 4421.9 per 100,000 population [2]. These disorders are more prevalent in women and rank among the top 25 causes of global disease burden, highlighting their significance as major public health challenges [3]. The COVID-19 pandemic further exacerbated this issue, leading to a substantial rise in mental health disorders. Major depressive disorders increased by 27.6%, and anxiety disorders by 25.6%, contributing an additional 53.2 million and 76.2 million cases globally, respectively [4]. This global increase in mood disorders emphasizes the importance of exploring modifiable lifestyle factors, such as diet, in mental health prevention and treatment.

Depression is characterized by persistent sadness, anhedonia, and impaired functioning, while anxiety manifests as excessive worry and physiological arousal, including tachycardia and respiratory changes [5]. These conditions have multifactorial etiologies involving genetic, neurobiological, environmental, and psychological components [6] and can be addressed through psychotherapeutic approaches, pharmacological interventions, and lifestyle modifications, including dietary changes [7].

Dietary modulation is gaining recognition as an effective adjunct to mental health treatments. Its advantages lie in being a low-cost, low-risk, and widely accessible intervention that may appeal to individuals who prefer non-invasive or preventive approaches [8], with growing evidence supporting the complex relationship between nutritional patterns and depression and anxiety [7]. Research consistently demonstrates that Mediterranean-style dietary patterns, characterized by abundant plant foods, lean proteins, healthy fats, and minimal ultra-processed foods, are associated with reduced depression risk and improved symptoms in clinical and non-clinical populations [9]. Conversely, Western dietary patterns high in processed foods, refined carbohydrates, and foods with high dietary inflammatory potential correlate with increased depression and anxiety symptoms [10,11].

The Mediterranean diet is widely recognized for its mental health benefits and its therapeutic role in managing chronic diseases such as obesity, diabetes, and cardiovascular conditions. Rich in anti-inflammatory and antioxidant components, this dietary pattern has been associated with improved cardiometabolic markers, reduced systemic inflammation, and better glycemic control. During the COVID-19 pandemic, when food-related stress and unhealthy eating behaviors were particularly prevalent, adherence to the Mediterranean diet emerged as a protective factor for physical and psychological well-being. Recent studies have highlighted its relevance in reducing COVID-19-related health risks, supporting immune function, and improving outcomes in patients with comorbid conditions [12,13,14]. These findings highlight the Mediterranean diet’s role in enhancing mental health and supporting effective treatment outcomes, both generally and specifically during global crises.

Multiple biological mechanisms explain the link between diet and mental health, including systemic inflammation, oxidative stress, and bidirectional communication via the gut–brain axis, where dietary components influence gut microbiota composition and function, affecting neurotransmitter production and neural signaling [15,16]. A Western diet rich in processed foods increases chronic inflammation in the body and leads to the release of inflammatory substances (cytokines) that cross the blood–brain barrier and contribute to depression and anxiety symptoms [17]. Conversely, diets rich in anti-inflammatory compounds, antioxidants, and essential nutrients can promote optimal neurotransmitter function, reduce systemic inflammation, and support beneficial gut microbiota, potentially improving mood regulation and the stress response [18,19]. Several biomarker studies support this mechanism, demonstrating that higher Mediterranean diet adherence is associated with lower levels of inflammatory markers such as C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-α) [18]. Western diets are also typically deficient in protective nutrients, including antioxidants, vitamins (such as B complex vitamins), and various minerals (such as zinc, iron, and magnesium) [20,21,22,23], dietary fiber, and omega-3 fatty acids, which collectively help regulate inflammation, maintain intestinal barrier integrity, support a healthy gut microbiome, and combat oxidative stress in both the gut and neural tissues [16,24]. These nutritional deficiencies compromise the optimal functioning of neuronal pathways, affecting neurotransmitter synthesis, including serotonin, which is heavily implicated in mood regulation and depression, and impairing immune regulation, all of which are critical for mental health.

Importantly, heightened inflammation is not only linked to mood disorders but also appears to influence treatment outcomes. Patients with depression and anxiety often exhibit elevated levels of inflammatory cytokines, and those with higher inflammation show reduced responsiveness to conventional psychopharmacological treatments, suggesting that inflammation may be a key factor in treatment resistance [25].

Emerging evidence from interventional studies strengthens the link between diet and mental health by demonstrating a causal relationship between dietary modifications and reductions in depressive symptoms. Randomized controlled trials indicate that adherence to Mediterranean diet interventions leads to clinically meaningful improvements in depression scores, with moderate to large effect sizes, even among individuals diagnosed with depression. A notable example of such a study is the SMILES trial, where the control group received structured social support, an intervention known for its mental health benefits [26]. Importantly, these benefits are most pronounced when dietary changes are implemented with structured, professional support, highlighting the potential of nutritional psychiatry as an adjunct to conventional treatments [7]. Beyond individual trials, large-scale meta-analyses provide compelling support for the role of diet in mental health. For instance, high consumption of ultra-processed foods has been associated with a significantly increased risk of developing mental disorders (53%), depression (44%), and anxiety (48%) [27]. Conversely, transitioning to a Mediterranean diet has been linked to significant reductions in depressive symptoms, reinforcing its potential as a preventive and therapeutic strategy [28]. These findings highlight the importance of integrating dietary interventions into mental health care, particularly given the substantial comorbidity between mood disorders and metabolic health issues.

Given the accumulating evidence linking dietary patterns with mental health outcomes, further research is needed to understand these associations across diverse populations and cultural contexts. The primary objective of this study was to investigate the relationship between adherence to a Mediterranean diet and symptoms of anxiety and depression among Israeli adults. The secondary objective was to examine the association between processed food consumption and symptoms of anxiety and depression and to explore whether sleep quality moderates these relationships. While this study was conducted within the Israeli population—one experiencing heightened mental health challenges, as evidenced by a 20% increase in anti-anxiety medication use following the Iron Swords War in October 2023 [29]—its findings have broader relevance for understanding how dietary patterns influence mental health. By examining these associations, this research contributes to the growing global body of evidence on modifiable lifestyle factors that shape mental health across diverse cultural and societal contexts.

2. Methods

2.1. Procedure

The current study was a cross-sectional, descriptive study employing survey methodology to examine the relationships between dietary patterns and health-related behaviors, including sleep quality and duration, physical activity, and mental health outcomes. Approval for the study was obtained from the Ashkelon Academic College Ethics Committee (approval #54-2024). The survey questionnaire was conducted via Qualtrics (Qualtrics, Provo, UT, USA) and distributed electronically through multiple digital channels, including messaging platforms (WhatsApp, Menlo Park, CA, USA), social media networks (Instagram, Menlo Park, CA, USA and Facebook, Menlo Park, CA, USA), and email distribution lists. This multi-platform recruitment strategy was employed to maximize reach and diversity within our target population. Participants accessed the survey via a secure link that directed them to the questionnaire platform. The study took place between 29 December 2024 and 1 March 2025. The survey introduction page outlined the study’s objectives and assured participant anonymity. Completion of the questionnaire served as documentation of participants’ voluntary informed consent. Participants retained the right to withdraw at any point during the survey process, and question responses were not mandatory.

A total of 303 responses were recorded, of which n = 253 completed the full questionnaire. Participants with missing data (n = 50) were compared to those with complete data across all demographic and outcome variables using independent samples t-tests for continuous variables and chi-square tests for categorical variables. No significant differences were found between groups, suggesting data were missing at random.

The study was reported in accordance with the STROBE guidelines for cross-sectional research [30] (see Appendix A).

2.2. Tools

Questionnaires were submitted electronically and consisted of four parts: demographic and health-related data, including age, gender, relationship status (in a relationship—Yes/No), socioeconomic status (above average, average, or below average), education, and religion, and health-related information, including weight and height, to calculate body mass index, or BMI (Kg/m²), physical activity frequency, and sleep duration and quality. Diet-related questions included adherence to the Mediterranean diet and processed food consumption; and mental-health-related questions included depressive symptoms and anxiety symptoms.

Physical activity was assessed using a single-item measure evaluating participants’ physical activity levels during the previous week. This measure demonstrates high reliability with a correlation of 0.86 and concurrent validity (compared to the Global Physical Activity Questionnaire [GPAQ]) with a correlation of r = 0.53 [31]. Participants were asked: “During the past 7 days, on how many days did you perform physical activity for at least 30 min per day?”

Sleep quality and duration were evaluated using the Pittsburgh Sleep Quality Index (PSQI), which assesses sleep patterns over the preceding month. This study specifically utilized the sleep quality and duration components, following the methodology of Buysse et al. [32], who reported an internal consistency (Cronbach’s alpha) of 0.83 [32]. The combined score for quality and duration of sleep ranged from 0 to 6, with 0 representing optimal sleep (very good subjective quality and >7 h duration) and 6 indicating the poorest sleep (very bad subjective quality and <5 h duration). A previously translated and validated Hebrew version of the PSQI demonstrated an internal consistency of Cronbach’s alpha of 0.72 [33].

Diet quality was assessed using the Israeli Mediterranean diet screener (IMEDAS) [34], a tool designed to evaluate adherence to the Mediterranean dietary pattern. The index comprises 17 questions measuring Mediterranean diet adherence through consumption frequency of characteristic foods (olive oil, vegetables, fruits, whole grains, legumes, and fish) and non-characteristic foods (red meat, sweet pastries, and salty snacks). Each question awards one point for meeting specific criteria, either consuming sufficient amounts of characteristic Mediterranean foods or limiting consumption of non-characteristic foods like processed items, and zero points for non-adherence. Scores range from 0–17, with higher values indicating greater Mediterranean diet adherence. A score of 9 or above represents good adherence. For this study, the alcohol consumption question was omitted.

The processed food scale was developed using four components from the IMEDAS questionnaire (sweet pastries, salty pastries, salty snacks, and processed meats). Rather than employing the traditional binary coding system (0 or 1), a quantitative approach based on serving sizes consumed was implemented. The serving sizes across all four components were summed to calculate total processed food consumption, providing a continuous measure where higher totals indicated greater consumption. This approach allowed for a more nuanced assessment of processed food intake, accounting for the quantity consumed. Sweetened beverages were excluded from this scale due to extreme outliers in individual consumption patterns (with some participants reporting more than 70 weekly servings per person) that significantly skewed the distribution.

Anxiety symptoms were assessed using the GAD-7 questionnaire: The GAD-7 is a validated screening and assessment tool for measuring the severity of anxiety symptoms. The questionnaire was developed by Spitzer et al. [35] and had been translated and validated in Hebrew [35]. The questionnaire consisted of 7 items describing common symptoms of generalized anxiety disorder, where respondents were asked to rate the frequency of symptom occurrence in the past two weeks on a 4-point Likert scale (0 = “not at all” to 3 = “nearly every day”). The score range is from 0 to 21, with higher scores indicating higher levels of anxiety [35]. The internal reliability of the questionnaire was found to be high, with Cronbach’s alpha of 0.90.

Depressive symptoms were measured using the Patient Health Questionnaire-9 (PHQ-9): The PHQ-9 is a validated screening and assessment tool for measuring the severity of depressive symptoms. The questionnaire was developed by Kroenke et al. [36] and had been translated and validated in Hebrew [36]. The questionnaire consisted of 9 items based on the criteria for diagnosing major depression according to the DSM, where respondents were asked to rate the frequency of symptom occurrence in the past two weeks on a 4-point Likert scale (0 = “not at all” to 3 = “nearly every day”). The score range is from 0 to 27, with higher scores indicating higher levels of depression [36]. The internal reliability of the questionnaire was found to be high, with Cronbach’s alpha of 0.89

2.3. Statistical Analysis

All analyses were conducted using SPSS version 27 (IBM, Armonk, NY, USA), with statistical significance set at p < 0.05. Missing data were handled using listwise deletion after confirming no significant differences between participants with complete versus incomplete data across all study variables. First, descriptive statistics of participant characteristics were conducted, including socio-demographic information, lifestyle and health-related information (BMI, physical activity frequency, and sleep quality and duration), mental health indicators (anxiety and depression symptoms), and dietary pattern indicators (Mediterranean diet adherence and consumption of processed foods), and were assessed for all participants (n = 303). Second, Pearson correlations were performed to explore relationships between dietary patterns, mental health symptoms, and health-related behaviors. Third, we conducted independent samples t-tests to examine potential differences in eating patterns between high and low anxiety/depression, as determined by the cut points of GAD-7 ≥ 8 for anxiety [37] and PHQ-9 ≥ 10 for depression [38]. Fourth, to examine the relationships between dietary patterns, health-related behaviors, and depression and anxiety symptoms, separate hierarchical regression analyses were conducted for depression (PHQ-9) and anxiety (GAD-7) symptoms as outcome variables. Variables were entered into four sequential blocks: (1) demographic factors (age, gender, socioeconomic status, and relationship status); (2) health-related behaviors (BMI and physical activity); (3) dietary patterns (Mediterranean diet adherence and processed food consumption); and (4) sleep quality. Sleep quality was entered in the final block due to its known strong association with mental health outcomes and to examine its independent contribution beyond dietary patterns. For each block, R², changes in R², 95% confidence intervals (CI), significance, and standardized coefficients were analyzed to determine each predictor’s significance and relative contribution. Potential confounding variables were included as covariates based on established relationships with both dietary patterns and depression in prior research. We included age and gender as demographic factors that influence dietary choices and depression risk [39]. Socioeconomic status was included due to its well-documented impact on both food access and mental health outcomes [40]. BMI was included as it established bidirectional relationships with both dietary intake and depression [41,42]. Physical activity was incorporated as a covariate due to its independent effects on both nutritional choices and mood regulation through neurobiological pathways [43,44,45]. Relationship status was included based on prior evidence suggesting that being in a relationship affects both eating behaviors through shared meal patterns and food environments [46] and provides social support that influences depression risk [47,48]. Fifth, mediation analyses were conducted using the PROCESS macro for SPSS [49] to examine whether sleep quality and duration mediated the relationship between Mediterranean diet adherence and mental health outcomes (depression and anxiety symptoms). Simple mediation models were specified with 5000 bootstrap samples to estimate direct and indirect effects with 95% confidence intervals. Mediterranean diet scores were entered as the independent variable (X), mental health measures (depression/anxiety) as the dependent variables (Y), and sleep parameters as the potential mediators (M).

3. Results

3.1. Sample Characteristics

Sample demographics, participants’ health-related factors, mental health, and dietary pattern indicators are shown in

Table 1. Demographics, health-related factors, mental health, and dietary pattern indicators, with % and number (n = 303).

Variables	Mean/N	SD or %N
Demographics
Age (n = 303)	32.6	11.1
Gender (n = 303)
Female	n = 233	76.9%
Male	n = 70	231%
Socioeconomic status (n = 301)
Below average	n = 40	13.3%
Average	n = 174	57.8%
Above average	n = 87	28.9%
Relationship status (n = 103)
In a relationship	n = 172	56.8%
Not in a relationship	n = 131	43.2%
Religion
Jewish	n = 298	98.3%
Muslim	n = 5	1.7%
Health-Related Factors
BMI (n = 299)	25.5	6.2
Physical activity frequency (n = 298)
None (0 days/week)	n = 114	38.3%
Low (1–2 days/week)	n = 91	30.5%
Moderate (3–4 days/week)	n = 64	21.5%
High (5–7 days/week)	n = 29	9.7%
Sleep duration and quality * (n = 282)	2.72	1.33
Mental Health Indicators
Depression: DHQ-9 * (n = 286)	11.5	6.8
Anxiety: GAD-7 * (n = 290)	10.1	5.5
Dietary Pattern Indicators
Mediterranean diet * (n = 253)	6.2	2.2
Processed food consumption ** (n = 253)	7.7	5.1

* Score. ** Servings. SD = Standard Deviation.

. The study sample (N = 303) consisted predominantly of Jewish (98.3%) females (76.9%) with an age range of 20–74 and a mean age of 32.6 years (SD = 11.1). Most participants reported average or above-average socioeconomic status (86.7%), and over half were in a relationship (56.8%). Health indicators revealed that participants had a mean BMI of 25.5 (SD = 6.2), with the majority (61.7%) engaging in physical activity at least once weekly, though over a third (38.3%) reported no regular physical activity. Mental health measures indicated moderate levels of depression (DHQ-9 M = 11.5, SD = 6.8) and anxiety (GAD-7 M = 10.1, SD = 5.5). The dietary assessment showed moderate-to-low adherence to the Mediterranean diet (IMEDAS M = 6.2, SD = 2.2) alongside substantial processed food consumption (M = 7.7, SD = 5.1).

3.2. Relationships Between the Study Variables

Pearson correlations were conducted to explore relationships among dietary patterns (adherence to the Mediterranean diet and consumption of processed food), mental health symptoms (anxiety and depression), health-related behaviors (physical activity frequency and sleep quality and duration), and age. As shown in

Table 2. Relationships between the study variables.

	Mediterranean Diet	Processed Food	Sleep Disturbance	Age
Processed Food	−0.438 ***
Physical Activity	0.272 ***		−0.136 *
Anxiety	−0.202 **	0.141 *	0.148 *	−0.219 ***
Depression	−0.176 **	0.150 *	0.227 ***	−0.237 ***

* p < 0.05, ** p < 0.01, *** p < 0.001.

, Mediterranean diet adherence showed significant negative correlations with both anxiety (r = −0.202, p = 0.001) and depression (r = −0.176, p = 0.005) and was negatively associated with processed food consumption (r = −0.438, p < 0.001). Conversely, processed food consumption demonstrated significant positive correlations with anxiety (r = 0.141, p = 0.026) and depression (r = 0.150, p = 0.018). Sleep disturbance was significantly associated with both anxiety (r = 0.148, p = 0.014) and depression (r = 0.227, p < 0.001), with a stronger relationship observed for depression. Physical activity frequency was positively correlated with Mediterranean diet adherence (r = 0.272, p < 0.001) and negatively associated with sleep disturbance (r = −0.136, p = 0.022). Age demonstrated significant negative correlations with anxiety (r = −0.219, p < 0.001) and depression (r = −0.237, p < 0.001), suggesting that younger individuals reported higher levels of anxiety and depression symptoms.

Independent samples t-tests were conducted to compare demographic factors, health behaviors, and sleep quality and duration between participants with high versus low anxiety (using the established GAD-7 cut-off score of ≥8) [36]. Results shown in

Table 3. Differences between low and high anxiety and depression scores.

Variable	PHQ-9 Depression Scale Low n = 124, High n = 162				t (df)	p Value
	Low		High
	M	SD	M	SD
Age	34.9	11.8	30.9	10.2	2.996 (238.884)	0.003
Physical activity (days/week)	2.0	2.0	1.6	1.8	1.663 (284)	0.097
BMI	25	5.1	25.9	6.7	−1.241 (279.783)	0.216
Mediterranean diet scale	6.5	2.3	5.9	2.1	2.250 (227.783)	0.025
Processed food consumption					−1.440 (248)	0.151
Sleep scale	2.4	1.2	2.9	1.4	−3.592 (268)	<0.001
	GAD-7 Anxiety Scale Low n = 100, High n = 190
Age	35.5	12.4	31.1	9.9	3.075 (164.777)	0.002
Physical activity (days/week)	1.9	1.9	1.7	1.9	0.544 (288)	0.587
BMI	25.3	5.3	25.5	6.4	−0.226 (284)	0.821
Mediterranean diet scale	6.7	2.3	5.9	2.1	2.690 (251)	0.008
Processed food consumption	6.8	4.9	8.1	5.1	−1.828 (248)	0.069
Sleep scale	2.5	1.3	2.8	1.3	−1.755 (272)	0.080

SD = Standard Deviation. df = Degrees of freedom.

revealed that participants with high anxiety were significantly younger and reported lower Mediterranean diet adherence compared to the low-anxiety group (p = 0.002 and p = 0.008, respectively). Additionally, the high-anxiety group showed trends toward higher processed food consumption and poorer sleep quality and duration, though these differences were marginally non-significant (p = 0.069 and p = 0.080, respectively). No significant differences were observed for physical activity or BMI between groups.

Similarly, when comparing participants with high versus low depression (using the established PHQ-9 cut-off score of ≥10) [38], those with higher depression symptoms were significantly younger (p = 0.003) and reported lower Mediterranean diet adherence (p = 0.025) than participants with low depression symptoms. Unlike the anxiety comparison, the difference in sleep quality and duration between depression groups reached statistical significance (p < 0.001), with the high-depression group reporting substantially poorer sleep. While the high-depression group also consumed more processed foods than the low-depression group, this difference did not reach statistical significance (p = 0.151). Similar to the anxiety analysis results, no significant differences in physical activity or BMI were observed between the low and high depression groups.

3.3. Regression Models

In the hierarchical regression analyses (

Table 4. Hierarchical regression analyses predicting anxiety symptoms.

	Combined Diet			Mediterranean Diet Only			Processed Food Only
	R2 (ΔR2)	β	95% CI	R2 (ΔR2)	β	95% CI	R2 (ΔR2)	β	95% CI
Model 1 a	0.163 ***			0.163 ***			0.163 ***
Model 2 b	0.170 (0.007)			0.169 (0.006)			0.170 (0.007)
Model 3 c	0.194 * (0.025 *)			0.190 * (0.021 *)			0.189 * (0.019 *)
Mediterranean diet		−0.093	(−0.611, 0.132)		−0.153 *	(−0.696, −0.071)		-----	-----
Processed food		0.101	(−0.041, 0.254)					0.142 *	(0.020, 0.282)
Model 4 d	0.209 * (0.014 *)			0.204 * (0.014 *)			0.204 * (0.016 *)
Mediterranean diet		−0.084	(−0.585, 0.154)		−0.146 *	(−0.675, −0.053)		-----	-----
Processed food		0.105	(−0.036, 0.257)		----	----		0.142 *	(0.021, 0.281)
Sleep		0.126 *	(0.009, 1.028)		0.123 *	(0.002, 1.014)		0.130 *	(0.029, 1.045)

^a Model 1: Demographics (age, gender, relationship status, and socioeconomic status). ^b Model 2: Model 1 + health-related behaviors (BMI and physical activity). ^c Model 3: Model 2 + dietary patterns. ^d Model 4: Model 3 + sleep quality. * p < 0.05, *** p < 0.001. Note: standardized beta coefficients (β) and 95% confidence intervals (CI) for dietary patterns and sleep quality are from Models 3 and 4. Combined diet models include both the Mediterranean diet and processed food variables simultaneously.

for anxiety,

Table 5. Hierarchical regression analyses predicting depression symptoms.

	Combined Diet			Mediterranean Diet Only			Processed Food Only
	R2 (ΔR2)	β	95% CI	R2 (ΔR2)	β	95% CI	R2 (ΔR2)	β	95% CI
Model 1 a	0.199 ***			0.199 ***			0.199 ***
Model 2 b	0.214 (0.015)			0.212 (0.013)			0.214 (0.015)
Model 3 c	0.235 * (0.022 *)			0.226 * (0.014 *)			0.234 * (0.020 *)
Mediterranean diet		−0.051	(−0.600, 0.282)		−0.126 *	(−0.756, −0.011)		----	----
Processed food		0.123	(−0.016, 0.335)		----	----		0.146 *	(0.034, 0.344)
Model 4 d	0.281 *** (0.045 ***)			0.271 *** (0.045 ***)			0.280 *** (0.046 ***)
Mediterranean diet		−0.035	(−0.538, 0.321)		−0.112	(−0.705, 0.022)		----	----
Processed food		0.130	(−0.002, 0.339)		----	----		0.146 *	(0.038, 0.339)
Sleep		0.223 ***	(0.528, 1.712)		0.221 ***	(0.521, 1.703)		0.225 ***	(0.539, 1.719)

^a Model 1: Demographics (age, gender, relationship status, and socioeconomic status). ^b Model 2: Model 1 + health-related behaviors (BMI and physical activity). ^c Model 3: Model 2 + dietary patterns. ^d Model 4: Model 3 + sleep quality. * p < 0.05, *** p < 0.001. Note: standardized beta coefficients (β) and 95% confidence intervals (CI) for dietary patterns and sleep quality are from Models 3 and 4. Combined diet models include both the Mediterranean diet and processed food variables simultaneously.

for depression), dietary patterns (Model 3) collectively contributed significant additional variance in both anxiety symptoms (ΔR² = 0.025, p = 0.035) and depression symptoms (ΔR² = 0.022, p = 0.045) beyond demographics and health-related behaviors. However, when examined simultaneously within the models, neither Mediterranean diet adherence nor processed food consumption reached clear statistical significance individually, despite their collective significance. For depression, processed food consumption approached significance (β = 0.130, p = 0.053). The addition of sleep duration and quality (Model 4) significantly improved model fit for both anxiety (ΔR² = 0.014, p = 0.046) and depression (ΔR² = 0.045, p < 0.001), with a notably stronger effect observed for depression symptoms.

When examining dietary patterns separately in relation to anxiety symptoms, individual regression models revealed that both dietary patterns maintained significance even after controlling sleep quality. The Mediterranean diet model showed that higher adherence was significantly associated with reduced anxiety symptoms (β = −0.146, p = 0.022) after controlling demographic factors, health-related behaviors, and sleep quality. Similarly, processed food consumption was significantly associated with increased anxiety symptoms (β = 0.142, p = 0.023) independent of sleep quality. Mediterranean diet adherence explained 2.1% of the unique variance (ΔR² = 0.021, p = 0.016) in anxiety symptoms, while processed food consumption accounted for 1.9% (ΔR² = 0.019, p = 0.024). In both models, sleep quality contributed approximately 1.5% additional explained variance, demonstrating that dietary patterns and sleep quality represent distinct pathways associated with anxiety symptoms.

Similar findings emerged when examining dietary patterns separately in relation to depression symptoms. In the Mediterranean diet model, higher adherence was significantly associated with reduced depression symptoms (β = −0.126, p = 0.043), explaining 1.4% unique variance (ΔR² = 0.014, p = 0.043) after controlling for demographics and health-related behaviors. After adding sleep quality in the final block, Mediterranean diet adherence approached but no longer reached statistical significance (β = −0.112, p = 0.065). Likewise, processed food consumption was significantly associated with increased depression symptoms (β = 0.146, p = 0.017), accounting for 2.0% of the unique variance (ΔR² = 0.020, p = 0.017), and remained significant after controlling for sleep quality (β = 0.146, p = 0.014). Sleep quality demonstrated a stronger relationship with depression than with anxiety, contributing 4.5–4.6% additional explained variance (p < 0.001) in both dietary models. Formal mediation analyses, however, did not support sleep quality and duration as a significant mediator of the relationship between the Mediterranean diet and either depression (indirect effect = −0.088, 95% CI [−0.218, 0.012]) or anxiety (indirect effect = −0.045, 95% CI [−0.121, 0.006]). These findings suggest that dietary patterns and sleep quality represent distinct pathways to mental health outcomes rather than a causal sequence where diet influences mental health through sleep-related mechanisms.

4. Discussion

The present study examined the relationships between dietary patterns, health-related behaviors, and mental health outcomes among 303 adult participants in Israel. Our results demonstrated significant associations between dietary patterns and mental health symptoms. First, our results revealed that both Mediterranean diet adherence and processed food consumption demonstrated relationships with anxiety and depression symptoms when examined in separate models. Mediterranean diet adherence was inversely associated with both anxiety and depression, consistent with previous research suggesting the protective effects of this dietary pattern on mental health [50,51]. Conversely, processed food consumption showed positive associations with anxiety and depression symptoms, aligning with a growing body of evidence linking ultra-processed food intake to poorer mental health outcomes [7,10,26,27]. Highly processed foods, characterized by a high glycemic load, unhealthy fats, artificial additives, and low fiber content, are known to contribute to systemic inflammation, oxidative stress, and gut microbiota dysbiosis, all of which have been implicated in the pathophysiology of mood disorders [17]. Notably, the pro-inflammatory nature of processed foods may contribute to treatment-resistant depression, as individuals with higher baseline inflammation levels tend to exhibit poorer responses to conventional antidepressant therapies [25,52,53]. Interestingly, when both dietary patterns were included simultaneously in our models, their individual effects were attenuated, suggesting shared variance between these dietary measures. This finding emphasizes the challenge of isolating the effects of specific dietary patterns, as food consumption behaviors often cluster together. For example, individuals who adhere more to Mediterranean diet components typically consume fewer processed foods [54,55].

Our findings regarding the negative association between Mediterranean diet adherence and mental health symptoms align with established mechanisms involving antioxidants, anti-inflammatory compounds, and essential micronutrients that support neurotransmitter synthesis and reduce systemic inflammation [18,19,56,57].

The inclusion of the sleep quality and duration scale in our analyses revealed several important insights. Sleep quality demonstrated significant associations with both anxiety and depression symptoms, with a notably stronger relationship observed for depression. This aligns with the extensive literature documenting the bidirectional relationships between sleep disturbances and depressive symptoms [58,59]. Compared to previous studies, the present research offers several advantages, including the simultaneous examination of both adherence to the Mediterranean diet and consumption of ultra-processed foods within the same model, the inclusion of multiple behavioral and demographic covariates, and the focus on an understudied, community-based Israeli adult population. While sample characteristics limit generalizability, these elements contribute to our understanding of dietary patterns and mental health outcomes in specific cultural contexts

We did not find evidence that sleep quality mediates the relationship between dietary patterns and mental health outcomes. Rather, our findings suggest that dietary patterns and sleep quality represent distinct pathways to mental health. The attenuation of the Mediterranean diet effect on depression after controlling for sleep quality, coupled with the persistence of the processed food effect, possibly suggests differential mechanisms through which these dietary factors might influence mental health. However, given that sleep duration and quality were self-reported, future studies using objective sleep measures (e.g., actigraphy and polysomnography) may offer more definitive conclusions on this potential interaction.

Interestingly, while Mediterranean diet adherence was associated with improved mental health outcomes [60,61], its effect on depression symptoms was attenuated after controlling for sleep quality [62]. This suggests that sleep may partially explain the protective effects of healthy eating on mood but does not fully account for the observed relationships [62]. By contrast, processed food consumption remained a robust predictor of depressive symptoms, even after adjusting for sleep quality, indicating that the detrimental effects of poor diet on mental health may operate through pathways distinct from those of sleep disturbances [63].

Several demographic and health-related factors emerged as significant predictors of mental health outcomes. Younger age was associated with higher levels of anxiety and depression symptoms, a finding consistent with epidemiological data indicating that mental health disorders disproportionately affect younger adults [64,65]. This may reflect greater socioeconomic stressors, lifestyle instability, and increased exposure to digital stressors (e.g., social media use) in younger populations [66,67,68,69,70].

Relationship status also played a role, with individuals in a relationship reporting lower levels of anxiety and depression. This aligns with research highlighting the protective effects of social support and intimate relationships on psychological well-being [47,48]. However, the extent to which relationship status interacts with dietary habits remains unclear and warrants further investigation.

Interestingly, physical activity frequency was not a significant predictor of mental health symptoms in our models, despite substantial evidence supporting its benefits for psychological well-being [45]. One possible explanation is that the measure used in this study, a single-item self-report assessment, may not have adequately captured exercise intensity, duration, or adherence to structured physical activity routines.

These findings have important implications for both clinical practice and public health policy. Given the growing recognition of lifestyle medicine as an adjunct to conventional psychiatric treatment, healthcare providers should consider incorporating dietary assessments and interventions into mental health care. Encouraging adherence to the Mediterranean diet and reducing processed food consumption could serve as a low-risk, cost-effective strategy to improve psychological well-being, particularly for individuals with mild-to-moderate mood disorders.

At the policy level, these results support nutritional education initiatives aimed at promoting whole-food-based diets and limiting ultra-processed food availability, particularly in schools, workplaces, and healthcare settings. Given the observed mental health benefits associated with a Mediterranean-style diet, public health campaigns should emphasize the psychological advantages of balanced eating patterns alongside traditional physical health benefits (e.g., cardiovascular protection and metabolic regulation).

Recent evidence suggests that combining dietary intervention with other treatment modalities may yield additive or synergistic effects. A randomized controlled trial conducted among postmenopausal women with obesity demonstrated that a combined dietary and physical–cognitive exercise intervention significantly improved executive function, adiponectin levels, and lipid profiles [71]. Similarly, research involving obese adolescents showed that integrating exercise and dietary changes significantly enhanced cognitive and physical self-control and reduced BMI [72]. These findings support the notion that dietary modification may serve as an effective adjunct therapy to psychological and physical interventions, especially within lifestyle-focused treatment frameworks.

4.1. Study Limitations

This study has several limitations that should be acknowledged. First, its cross-sectional design prevents us from drawing causal inferences about the relationships between dietary patterns, sleep quality, and mental health outcomes. While our findings suggest associations between Mediterranean diet adherence, processed food consumption, and symptoms of anxiety and depression, we cannot determine whether dietary habits influence mental health or if individuals experiencing psychological distress are more likely to adopt poorer eating behaviors. Future longitudinal studies and randomized controlled trials are needed to establish directionality and causality. Second, self-report measures were used to assess dietary intake, sleep quality, and mental health symptoms. While validated instruments were employed, self-reported dietary data may be subject to recall bias and social desirability bias, potentially leading to underreporting or overreporting of specific food groups. Another limitation is the lack of a comprehensive dietary assessment. While we examined Mediterranean diet adherence and processed food consumption, other nutritional factors, such as specific micronutrients (e.g., omega-3 fatty acids, vitamin D, and B vitamins) and macronutrient composition, were not directly analyzed. These components may play crucial roles in diet–mental health relationships. A critical limitation concerns the generalizability of our findings. Our sample characteristics substantially limit the external validity of our results. The study population was predominantly female (76.9%) and Jewish (98.3%), with a relatively young mean age of 32.6 years. This demographic composition raises important questions about the applicability of our findings to males, non-Jewish populations, and older adults. The biological and psychological mechanisms linking diet to mental health may function differently across gender, cultural background, and age due to hormonal variations, different stress responses, and age-related metabolic changes. Additionally, selection bias may have drawn participants already interested in nutrition–mental health connections. While our findings provide valuable insights into dietary and mental health patterns, caution should be exercised when extrapolating these results to populations with different demographic and cultural characteristics.

4.2. Perspective for Clinical Practice

The findings of this study provide practical implications for clinical and preventive mental health care. Given the observed associations between dietary patterns and symptoms of anxiety and depression, mental health practitioners should consider incorporating basic nutritional screening into routine assessments. Identifying individuals with low adherence to healthy dietary patterns, particularly those consuming high levels of processed foods, may support early intervention efforts.

While nutritional counseling is not traditionally part of psychiatric care, these results emphasize the potential of collaborative, interdisciplinary models involving dietitians, psychologists, and primary care providers. Such integration may be especially beneficial for patients with mild-to-moderate symptoms who are seeking non-pharmacological or adjunctive options. Furthermore, promoting adherence to Mediterranean-style diets may be a low-risk, cost-effective tool to enhance psychological well-being and reduce reliance on medication.

In clinical practice, interventions aimed at modifying diet should be tailored to the individual’s preferences, cultural background, and readiness for change. Educational strategies, motivational interviewing, and structured dietary programs may help translate evidence into action. Additionally, raising healthcare professionals’ awareness of food–mood connections could promote holistic treatment plans addressing both mental and physical health.

5. Conclusions

This study contributes meaningful evidence to the growing body of research examining the relationships between dietary patterns and mental health outcomes. Our findings revealed significant associations between Mediterranean diet adherence, processed food consumption, and symptoms of anxiety and depression among Israeli adults, which persisted after controlling for relevant demographic and health-related confounders. The observed inverse relationship between Mediterranean diet adherence and mental health symptoms, coupled with the positive association between processed food consumption and psychological distress, aligns with the emerging literature in nutritional psychiatry suggesting diet quality as a modifiable risk factor for mental health disorders.

Our analyses indicate that dietary patterns represent important pathways to mental health outcomes, with sleep duration and quality appearing as a distinct contributing factor rather than a mediating mechanism. This emphasizes the potential value of intervention approaches primarily targeting nutritional habits, while acknowledging the independent contribution of sleep to mental well-being.

These findings may support the integration of nutritional assessment and guidance into mental health treatment protocols. Healthcare providers should consider evaluating dietary patterns as part of comprehensive mental health assessments and incorporate evidence-based nutritional recommendations into treatment plans, particularly for individuals presenting with symptoms of anxiety and depression. In addition, it may assist health policymakers in promoting policies that support nutritional guidance, such as promoting Mediterranean dietary patterns and discouraging excessive consumption of processed foods, to prevent and support mental health issues, specifically anxiety and depression. While this study was conducted in Israel during a period of conflict, our findings contribute to our understanding of diet–mental health relationships, though generalizability to populations with different demographic and cultural characteristics should be approached with caution. In a time when mental health disorders are on the rise globally, dietary interventions represent a promising, low-risk, and accessible strategy for promoting psychological well-being. This study contributes to the growing evidence supporting the relationship between dietary patterns and mental health outcomes, advocating for a holistic, lifestyle-based approach to mental health care. Future research should focus on longitudinal designs to track changes over time and establish causal relationships between dietary factors and mental health outcomes. Additional interventional studies are needed to test the effectiveness of specific dietary interventions or the elimination of processed foods in improving mental health.