Association of macronutrient intake, physical activity, anxiety, and depression with sleep quality among Iranian male adolescents

Abstract

Background

Adolescence is a unique stage of life accompanied by physiological and psychological modifications, along with stress, confusion, and depression.

Materials and methods

The present descriptive-analytical cross-sectional research was done on 267 male adolescents who studied at high schools in Zanjan, Iran. Demographic characteristics questionnaires, a 48-item food frequency questionnaire, a short version of the International Physical Activity Questionnaire (IPAQ), the Depression Anxiety Stress Scale (DASS-21), and the Pittsburgh Sleep Quality Index (PSQI) were used to collect data.

Results

The mean ± standard deviation (SD) of age, weight, height, and sitting time was 15.94 ± 0.91 years, 68.53 ± 15.28 kg, 1.75 ± 0.06 m, and 449.25 ± 322.06 min, respectively. The study results showed that students with poor sleep quality showed a higher rate of depression than those with good sleep quality in the high and low physical activity groups (p < 0.05). The stress, depression, and anxiety scores significantly correlated with sleep quality in the physical activity groups (p < 0.05). The structural equation model analysis results showed that mental health directly affected sleep quality; this association was significant in the low physical activity group.

Conclusion

We found that sleep quality was independently related to mental health in young Iranian men. However, dietary intake was not a significant predictor of mental health or sleep quality. More studies are required to evaluate the association between dietary intake and sleep quality in adults.

Introduction

Adolescence can be defined as a period of rapid growth that begins with puberty. Transition from childhood to adulthood and changes in social, physical, and psychological aspects can cause stress, confusion, and depression [1]. Common traits during adolescence include irritability, depression, anxiety, and aggression. About 20% of the world’s population are adolescents [2]. According to previous studies, approximately 29% of Iranian boys have severe depression [3]. During puberty, the feeling of excitement increases and contributes to hypersensitivity and intense excitement [4]. Depression is a psychological disturbance associated with at least two weeks of low mood [5]. These include symptoms of low self-esteem, fatigue, slowing movements, and disturbed sleep [6, 7]. Emotional disorders, such as anxiety and depression, are involved in adolescence period stress. Stress, which results in mental health problems among adolescents, is caused by excessive pressure or any other force imposed on individuals [8, 9].

Anxiety is one of the most prevalent psychiatric diseases in the general population [10]. Anxiety is interpreted as an emotional response to sudden feelings of fear and intimidation. Some of the anxiety symptoms can be attributed to excessive fear and anxiety, and a tendency to be overly cautious and alert [11]. In global health, anxiety and stress are essential in adolescence. Every teenager experiences stress as a negative emotion that reacts to an enormous force. Stress and anxiety can cause sleep problems in anxious teens. However, common issues, including anxiety, sleep disorders, and depression, have been observed in adolescents due to the unique characteristics of this period of life. Sleep is essential for physical and mental development and plays a crucial role in supporting adolescent health. Some evidence suggests that health issues, such as overweight, obesity, and non-communicable diseases (e.g., diabetes), are associated with sleep disorders [12]. Recent research has indicated that the association between sleep disturbance, anxiety, and depression is bidirectional [13].

As reported by some studies, sleep disorders can enhance the risk of obesity and overweight in adolescents [14, 15]. Despite the decline in malnutrition, overweight and obesity have risen among teenagers in developing countries [16]. The rate of obesity and overweight among Iranian adolescents (12–18 years) has been reported as 6.5% [17]. Moreover, some cardiometabolic disorders in teenagers and children are caused by anxiety, depression, and sleep disturbance as emotional disorders [18]. During adolescence, most eating behaviors evolve and play a role in predicting future health status [19].

Adolescence is a unique stage of life accompanied by physiological and psychological modifications. Children’s refusal to eat nutritious foods, such as fruits or vegetables, can lead to food imbalances and growth failure [20]. Moreover, there is evidence that fruits and vegetables have protective effects against depression and anxiety [20, 21]. A healthy diet that includes low-fat dairy products, non-refined grains, and meat is correlated with lower depression [22]. In addition, the consumption of macronutrients and calories can affect sleep quality [15]. We hypothesize that people with low sleep quality, low physical activity, and insufficient dietary intake have more depression, anxiety, and stress.

Due to the high prevalence of obesity and overweight among Iranian adolescents, the current study was conducted to determine the relationship of the diet of Iranian adolescents with anxiety, depression, and sleep quality. Dietary intake as a modifiable risk factor may have a role in preventing and treating depression and anxiety in adolescence.

Materials and methods

The present descriptive-analytical cross-sectional research was done during 2019–2020. The research population included 265 male adolescents aged 15–18 years in the high schools of Zanjan City, Iran, who were selected by the randomized multistage cluster sampling technique. Selection of schools and classes (9th to 10th grades) was performed through cluster sampling from a complete list of schools. Furthermore, the students were selected using systematic sampling from the students studying in the considered classes who met the inclusion criteria (students whose parents had signed the consent form, agreed to participate, and aged 15–18 years).

Based on the study design, students who took psychiatric medications or had a history of serious or mental diseases, physical disabilities, apparent physical injuries, divorce, death, remarriage of parents, running away from home, or doing professional sports were excluded. In addition, failure to answer over 20% of the questions of the questionnaire was regarded as an exclusion criterion. Five questionnaires utilized in this study included demographic characteristics questionnaires, a 48-item food frequency questionnaire, the Depression Anxiety Stress Scale (DASS-21), the Pittsburgh Sleep Quality Index (PSQI), and a short version of the International Physical Activity Questionnaire (IPAQ). The researcher attended the considered classes and distributed the questionnaires. The students completed the questionnaires at intervals between classes and returned them to the researcher.

Ethical considerations

The Research Committee of Zanjan University of Medical Sciences approved the study. Before data gathering, written informed consent was obtained from the parents and students.

Dietary assessment

A 48-item food-frequency questionnaire was used for dietary assessment. The subjects reported their daily, weekly, or monthly frequency of consuming different food items over the preceding year in an open-ended format. They selected the “never/seldom” response if they had never eaten a given food item. The declared frequency of each food item was converted into daily consumption. Never and seldom were regarded as “zero” [23, 24].

Anthropometric evaluation

Height and weight measurements were taken following standard procedures, without shoes and wearing lightweight clothing, to the nearest 0.1 unit (cm for height and kg for weight). Body mass index (BMI) was computed from the weight and height [BMI = Wt (kg)⁄Ht(m²)] [25]. Waist circumference (WC) was recorded directly on the skin, at the midpoint between the lower edge of the ribs and the top of the hip bone, at the end of a normal breath out, to the nearest 0.1 cm [26]. The measurement of hip circumference (HC) was done at the fullest part of the hips, level with the greater trochanter, and recorded to the nearest 0.1 cm.

Depression questionnaire

Symptoms of depression in our population were assessed using DASS. This questionnaire was conceptualized as a 42-item assessment including of three subscales with 14 items. The items assess experienced symptoms in the previous week and are scored on a Likert scale ranging from 0 (“does not apply to me at all”) to 4 (“most of the time applies to me”) [27]. The DASS-21 has three 7-item self-report scales obtained from the DASS full version [28].

Sleep quality evaluation

To evaluate sleep quality, we employed the validated PSQI. This tool quickly gathers self-reported data on sleep habits. Comprising 18 items, the PSQI gauges sleep quality and disruptions over the past few months. It provides insights into the participant’s self-perceived sleep quality, time taken to fall asleep, sleep efficiency, sleep duration, daytime dysfunctions, sleep disturbance, and use of sleep medication. These seven components contribute to a cumulative score ranging from 0 to 21, with the score for each part ranging from 0 to 3 [29].

Results

A total of 265 students were enrolled. The summary statistics of the variables are reported in Table 1. The mean ± standard deviation (SD) for age, weight, height, and sitting time was 15.94 ± 0.91 years, 68.53 ± 15.28 kg, 1.75 ± 0.06 m, and 449.25 ± 322.06 min, respectively. The average weight (g) of macronutrients and calorie intakes are also reported in Table 1.

Table 1 Summary statistics of the study variables

The mean and SD of depression, anxiety, and stress variables in the two groups of poor and good sleep quality are reported in Table 2.

Table 2 Comparison of the mean of depression, anxiety, and stress variables in good and poor sleep quality by different groups of physical activity

Students with poor sleep quality had higher depression rates compared to those with good sleep quality in the low and high physical activity groups (p < 0.05). No significant difference was detected between the depression of the two sleep quality groups in the moderate physical activity cohort. Moreover, the anxiety and stress levels of students with poor sleep quality were higher in the moderate physical activity group (p < 0.05) compared to the high physical activity group. The two sleep quality groups had no significant differences in terms of Table 1 variables.

The internal reliability of all scales was good. Cronbach’s alpha was 0.77 for the PSQI and 0.83 for DASS-21.

Before establishing multivariate regression models, correlations between the studied variables were assessed. The depression, anxiety, and stress scores were significantly correlated with sleep quality in the physical activity groups (p < 0.05; Table 3). Sleep quality and depression correlation coefficient were 0.4,0.372 and 0.454 in Low, moderate, and high physical activity groups, respectively. Correlation coefficient of sleep quality and anxiety were 0.265,0.424 and 0.242 in Low, moderate, and high physical activity groups, respectively.

Table 3 Correlations between study variables in physical activity groups

The structural equation model was made to describe possible relationships between sleep quality and the studied variables. The model and the detailed path coefficients are presented in Fig. 1.

The indices were two goodness of fit of the model were two good: $\:\raisebox{1ex}{${\varvec{\chi\:}}^{2}$}\!\left/\:\!\raisebox{-1ex}{$df$}\right.=1.167$, CFI, GFI, and RMSEA were 0.905, 0.992, and 0.025, respectively.

The model showed that mental health had a direct effect on sleep quality. This association was significant just in the low physical activity group. Mental health standardized regression coefficients were 1.055,0.730, and 0.937 for low, moderate, and high physical activity group respectively. The fat variable standardized regression coefficient was 0.316 in low, 3.278 in moderate, and 1.340 in high physical activity group.

Fig. 1

Final SEM model describing the Standardized direct effects between variables (Significance levels: * p < 0.001)

(Significance levels: * p < 0.001)

Discussion

Our study showed that sleep quality affects stress and anxiety, especially in the moderate physical activity group. Furthermore, a positive correlation was detected between the students’ sleep quality and their depression, stress, and anxiety in the physical activity groups. A structural equation model evaluated the association between sleep quality and macronutrients in the physical activity groups. The analysis showed that mental health was associated with sleep quality in the low physical activity group. This study hypothesizes that mental health mediates the longitudinal relationship between dietary intake and sleep quality.

It has been confirmed that the consumption of nutrients is associated with sleep quality and mental health. Based on our knowledge, the present study is the first to assess dietary intake’s direct and indirect effects on adolescents’ mental health and sleep quality using structural equation modeling in Iran. Consistent with the literature, our analysis supports the mediation effects of mental health on the association between dietary intake and sleep quality [30]. Contrary to our research, the association between mental health symptoms and sleep quality in female adolescents was shown in another study. In this study, the relationship between macronutrient intake and mental health in male students has been established but is not significant.

Sleep quality was not significantly associated with macronutrient intake in the present study. Previous investigations have demonstrated that sleep quality is not related to increased energy intake [31]. However, some studies found that shorter sleep duration was associated with higher energy intake among adolescents [32]. We also found an indirect negative effect of carbohydrate consumption on sleep quality. A previous study reported that energy intake from carbohydrates was not significantly associated with sleep quality [31]. In another research, adolescents having shorter sleep duration consumed more carbohydrates [32].

Seven aspects of sleep quality were assessed in this research. No significant association was detected between dietary intake and sleep quality. The relationship between diet and sleep quality is important because of the role of macronutrients in the secretion of hormones. Some studies have shown that insomnia is associated with weight gain [33, 34]. These observations may be due to appetite-mediating hormones, such as leptin and ghrelin. However, other studies do not support this view [35]. On the other hand, two important neurotransmitters regulating the sleep/wake cycle are serotonin and melatonin [36, 37]. Tryptophan is the precursor amino acid of melatonin and serotonin [38]. Foods that contain carbohydrates play a role in relaxation through serotonin, and protein makes sleep easier. Therefore, protein intake plays a role in improving sleep quality [38].

This is a cross-sectional study, and we suggest that it be conducted as a multicenter interventional study to investigate the effect of macronutrients and physical activity on sleep quality, anxiety, and depression.

Limitation

One of our limitations was the cross-sectional design of the study. In this study design, the causal relationship between sleep quality and dietary intake cannot be defined. The restriction in sample size is another limitation of this study. In addition, we cannot determine the interaction of consuming some nutrients with the intake of other nutrients. All participants in this study were young Iranian men. Therefore, the findings should not be generalized to females. Finally, we did not know about the stress experienced, socioeconomic factors, or the use of medications, such as adjuvants, which can affect eating behaviors and sleep quality.

Conclusion

This study revealed that sleep quality was independently related to mental health in young Iranian men. However, dietary intake was not a significant predictor of mental health or sleep quality. More studies are needed to evaluate the relationship between dietary intake and sleep quality in adults.