Exposure to psychosocial risks in work contexts has been one of the greatest challenges in occupational health policies. According to the World Health Organization (WHO), psychosocial factors such as the interactions between the environment and working conditions, organizational conditions, job roles and content, effort levels, and individual and family characteristics of workers play a significant role in workers’ mental health [1]. However, the nature of psychosocial factors is complex, involving issues related to health risks through social and psychological mechanisms of the general and work environment [2].

Work has been considered one of the sources of stress [3], with the main workplace stressors being the division of tasks in the work environment, precarious work organization conditions, low worker appreciation, and the lack of synchrony between the job description and what is performed in daily work practice. Stress is a state that causes wear and tear on the human body and/or a decrease in work capacity. On its own, stress cannot trigger an organic disease or cause significant dysfunction in an individual’s life, unless other conditions are present, such as organic vulnerability or an inadequate way of assessing and coping with the stressful situation; it can pose a health risk [4]. Furthermore, attitudes and behaviors towards food can be shaped by stress in a bidirectional manner, decreasing or increasing food consumption [3].

Souza et al. [5] emphasize that eating habits can be altered when individuals are subjected to psychosocial stress, contributing to unfavorable health outcomes such as obesity, biochemical and metabolic changes, and cardiovascular diseases.

Given the growing importance of studying the association between eating habits and health outcomes, several indices have been developed based on conceptual criteria of healthy eating and nutritional recommendations. These indices aim to provide a summary measure of the main characteristics of eating (diet variety, adequate intake of nutrients and food groups) [6]. These indices or scores facilitate the assessment of diet quality in populations or groups of individuals, since their components are generally quantified and, when added together, offer an overall measure of quality, such as Diet Variety Scores (DVS), which quantify the number of different foods consumed, which can be expressed over a period, a week, a month or a year or even a day, and the Diet Diversity Score (DDS), which expresses the consumption of food groups considered healthy [7]. In addition to these, the following indices have also been used: Nutrient Adequacy Ratio (NAR), which compares the individual daily intake of a nutrient with the Recommended Dietary Allowance (RDA), and the Mean Adequacy Ratio (MAR), which verifies the adequacy of nutrients for the nutrients selected for a given individual [8,9].

Psychosocial stress, which is associated with both increased and decreased food consumption, affects eating in a bidirectional manner. Around 40% of individuals reduce their food intake and lose weight during or after stress, while another 40% increase their food intake during stress [3].

Although some studies have been carried out on stress at work and its impact on dietary intake [10,11], no publications were found that correlate psychosocial stress with diet diversity and variety. Therefore, this study aimed to analyze the association between work-related stress and dietary variety and diversity scores among baseline participants of the ELSA-Brasil study.

Table 1 shows that dietary variety inadequacy occurred in 38.6% of participants with low psychological job demand, 42.9% of those with low job control, and 40.0% of those who reported high social support at work. Inadequate DVS was concentrated in men (39.7%), in the age group of 65 to 72 years old (42.9%), in those with incomplete primary education (69.3%), and in single individuals (40.3%). Furthermore, we observed that those who reported smoking habits (45.5%) and those classified as obese (42.3%) had higher proportions of inadequate variety. It is also observed that, among participants with inadequate diet diversity, those with the highest proportions were those with low psychological job demand (31.2%), low job control (31.5%), and low social support at work (31.1%). It is worth noting that inadequate diet diversity among women was 34.3%, 34.6% in the age group of 65 to 72 years old, 41.7% in those with incomplete elementary education, 34.0% in separated/widowed individuals, and 35.8% in those who reported being smokers.

The Mean Adequacy Ratio (MAR) was 93.0%, with higher scores in DVS and DDS associated with higher MAR percentages (Table 2).

Table 3 shows that participants with high job control have higher odds of inadequate diet variety compared to those with low job control, with statistical significance (OR 1.21, 95% CI: 1.11-1.32).

The results suggest a higher likelihood of inadequacy in the diet variety score among those with high job control. For the diet diversity score, the association with psychological demand and social support at work appears protective, although it lacks statistical significance.

The results of a meta-analysis showed that the relationship between stress and overall food consumption was of small magnitude, but these findings were aligned with previous narrative reviews, which suggested that food consumption could vary in response to stress among different individuals. Although the effect sizes were modest, they were significant, as they evidenced that stress impacts the consumption of healthy and unhealthy foods in a differentiated way [22]. On the other hand, when investigating the relationship between psychosocial stress at work and food compulsion, the results indicated a direct association, with BMI acting as a modifying factor [23].

Our results indicated that high psychological demand is positively associated with dietary variety, although this association lost statistical significance after adjustments. In a study involving 324 public servants from a public university in Ceará, using the DCSQ questionnaire and two dietary recalls, the results showed, in relation to dietary patterns with high psychological demand in the adjusted model, the patterns named mixed dietary pattern (tubers, poultry, eggs, pasta, smoothies, and cheeses) and prudent dietary pattern (grains, olive oil and oilseeds, skimmed dairy products and white cheeses, fruits) without statistical significance when compared to low psychological demand. The “vegetable, seafood, and infusions” dietary pattern (vegetables, leafy greens, coffee, tea, fish, and seafood) (PR=1.57; 95% CI 1.01–2.43) and the “energy-dense” dietary pattern (industrialized beverages, fast food, processed meats, ultra-processed foods, sugars and sweets, sweetened fruit juices and pulps) (PR=1.57; 95% CI 1.01–2.43) showed that high psychological demand was associated with a 57% higher prevalence ratio compared to low psychological demand. Conversely, the “common Brazilian” dietary pattern (bread, cakes and cookies, rice and risottos, beans and legumes, fats, meat) (PR=0.57; 95% CI 0.33–0.97) was found to be protective for individuals classified as having high psychological demand when compared to those with low psychological demand [24].

When evaluating control at work and the association with variety and diversity scores, individuals with high control showed a higher chance of risk for variety scores, and for diversity, the results indicated a borderline protective effect. In the adjusted model of public servants from a university in Ceará, the mixed and energy-dense patterns did not show statistical significance when comparing low control at work to high control. Regarding the prudent pattern (PR=0.43; 95% CI 0.27-0.70) and plant-based/vegetables pattern (PR=0.50; 95% CI 0.31-0.80) patterns, the results showed that low control at work has an inverse relationship when compared to high control at work [24].

Regarding social support, some studies corroborate our findings, i.e., social support at work as a protective factor, although we found a borderline association for diet inadequacy [24,25]. In the study by Monteiro Sampaio et al. [24] with public servants, those with low social support compared to those with high social support showed a higher risk for the common Brazilian dietary pattern, however, it was not statistically associated (PR=1.59; 95% CI 0.85-2.07). The prudent dietary pattern (PR=0.62; 95% CI 0.40-0.97) showed a protective relationship between those with low social support at work when compared to those with high social support. Furthermore, another study observed positive associations between diet and social support, such as the study that evaluated the association between dietary patterns and social support at work with Brazilian bank employees, aged 20 to 64 years, the authors showed that the “traditional and protein” pattern (beans, rice, meats and derivatives, eggs, French fries, breads and butter) showed risk for those with low social support when compared to those with high social support (PR=1.50; 95% CI 1.04-2.15) [26].

Ferranti et al. [27] also found in a study with workers from Emory University (Georgia/USA) that social support is associated with better diet quality for the diet quality indices evaluated: Alternate Healthy Eating Index (AHEI), Dietary Approaches to Stopping Hypertension (DASH) diet, and Mediterranean diet score. These results indicate that individuals with greater social support at work, maintaining a more active interaction among themselves, allow for greater adherence to a diet more related to local culture and healthier.

In the China Health and Nutrition Survey (CHNS) study, conducted with 7434 participants, the association between diet diversity score and perceived psychosocial stress, measured by the Perceived Stress Scale (PSS), was examined. The scale, validated for the Chinese population, has 14 items, with scores ranging from zero to 56, and a score >25 may have a certain degree of negative impact on a person’s physical and mental health. The result showed that those who had greater dietary diversity (scores ≥9, OR: 0.480, 95% CI: 0.300-0.770) in their daily diet were less likely to have a higher level of psychological stress, compared to participants with lower daily dietary diversity (scores = 3) (OR: 0.809, 95% CI: 0.521-1.258) [28].

The results found from the association of dietary diversity and psychosocial stress at work, observed in the ELSA-Brasil worker sample, show a protective relationship, similar to those found in the study with Chinese individuals. The proximity between the results, despite cultural and dietary differences, can be explained by the fact that the DDS is a tool that assesses the diversity of food groups consumed daily, considering the food culture of each individual. This tool uses a specific list of foods, which are organized into groups according to their nutritional similarities. This approach is based on healthy eating recommendations, which can indicate the consumption of a diversified diet.

In the PROMESTRE study, conducted with 502 teachers from 20 public schools in Londrina (Paraná, Brazil), in 2012 (1st wave) and 2015 (2nd wave), verifying the association between psychosocial stress at work, using the combination of low control at work, distinguishing four basic types of work experiences, generated by the interaction of “high” and “low” levels of psychological demand and control: “high job strain” (characterized as high demand and low control), “active work” (high demand and high control), “passive work” (low demand and low control), and “low job strain” (combining low demand and high control), verifying the weekly frequency of fruit and other vegetable consumption, the substitution of meals for snacks, and the removal of visible fat from red meat and the removal of skin from chicken meat, showed that teachers who reported high psychological demand and low control were more likely to reduce fruit consumption (coefficient = 0.064, 95% CI: 0.018, 0.109) and less likely to increase (coefficient = -0.066, 95% CI: 0.115, -0.016) the frequency of fruit consumption compared to teachers who reported low stress. Furthermore, teachers with passive work, i.e., low psychological demand and low control, were more likely to increase the frequency of skin removal from chicken meat (coefficient = 0.061, 95% CI: 0.014-0.108) compared to respondents with high stress at work [25].

The strength of these results is based on the ELSA-Brasil data, a large-scale multicenter cohort study with 15,105 participants, which applied rigorous measures to ensure data quality and used diet variety and diversity scores in relation to psychosocial stress. However, limitations are also found in the results, since it is a cross-sectional study, and temporality cannot be established, and reverse causality seems likely with diet, temporal evidence on the nature of the association is less clear, and associations may possibly be bidirectional and explainable by common causes. Furthermore, the variation among proposals regarding the number of food groups to be formed makes it difficult to reach a consensus on which and how many items and food groups should be grouped for the formation of scores. Additionally, the application of the diet variety score does not take into account the quantity of foods consumed within the groups, nor the variation within the group itself, i.e., the individual may always consume the same food within a food group that encompasses several other foods. Thus, there is no way to know whether the individual varied only the food groups or also the foods belonging to the same group.

Finally, the result of the work stress assessment is related to the sample of this study, composed of public servants, in which the levels of the DCSQ dimensions are also more similar, which can lead to an underestimation of the association measures.

In conclusion, the results show a positive association between control at work and diet variety. Although the observed odds ratios were not statistically significant, their borderline values suggest that psychological demand and social support at work may act as protective factors against inadequate diet diversity. It is worth noting that 80% of the population studied followed the recommendations for a varied and diversified diet, according to the indices used. These findings reinforce the importance of considering psychosocial aspects related to work when promoting a healthy diet, going beyond the simple focus on nutritional recommendations.