Journal of Sleep Medicine & Disorders

Cite this article: Lotfi M, Al-Hosseini MK, Jafarirad S (2015) The Relationship of Sleep Quality with Eating Behavior and Food Intake among Male University Students. J Sleep Med Disord 2(5): 1034.

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*Corresponding authorSima Jafarirad, Assistant Professor, Nutrition and Metabolic Disease Research Center, Ahvaz Jundishapur University of Medical Sciences, Ahvaz, Iran, Tel: 98-613-373-8317, Fax: 98-613-373-8330; Email:

Submitted: 07 October 2015

Accepted: 12 November 2015

Published: 13 November 2015

ISSN: 2379-0822

Copyright© 2015 Jafarirad et al.

OPEN ACCESS

Keywords•Sleep•Fruits•Dairy products•Eating behavior

Research Article

The Relationship of Sleep Quality with Eating Behavior and Food Intake among Male University StudentsMostafa Lotfi1, Mojtaba Khadem Al-Hosseini1 and Sima Jafarirad1,2*1Department of Nutrition, Ahvaz Jundishapur University of Medical Sciences, Iran2Nutrition and Metabolic Disease Research Center, Ahvaz Jundishapur University of Medical Sciences, Iran

Abstract

Objectives: Poor sleep quality can cause mental and physical fatigue. University students need quality sleep to focus on their lessons and physical activity. Therefore, the aim of this study was to investigate the prevalence of poor sleep quality and its relationship with some nutritional factors such as food intake and eating behavior among male students.

Methods: One hundred and eighty three male students at Ahvaz Jundishapur University of Medical Sciences participated in the study. Pittsburgh Sleep Quality Index and Dutch eating behavior questionnaires were completed. Intakes of different food groups (according to food pyramid) were evaluated by a brief instrument as well.

Results: Students with poor sleep quality consumed less fruits, doogh (traditional beverage) and total dairy products intake. It was observed that there is a significant relationship between poor sleep quality and emotional, restrained and external eating behaviors.

Conclusion: Healthy and balanced food intakes may help to reduce sleep problems, also eating behaviors might be included as relative factors with sleep quality.

ABBREVIATIONSBMI: Body Mass Index; PSQI: Pittsburgh Sleep Quality Index;

MET: Metabolic Equivalent; Trp: Tryptophan

INTRODUCTIONSleep is an important resting state and essential part of life

that could have effect on many aspects of life. Many factors have influence on the amount of sleep and adults need about 7-8 hours of sleep/day for best function [1]. There is an association between the quantity of sleep and chronic diseases such as, coronary heart disease [2], dyslipidemia [3], type 2 diabetes mellitus, hypertension, and obesity [4], some studies have shown a reverse relationship between body mass indexes (BMI) and sleep quantity [5]. Lifestyle factors such as physical activity and consumption of certain foods (e.g. coffee or alcohol drinks) have effect on the quality and quantity of sleep [6]. There are some studies on the effect of sleep quantity on diet and meal pattern, which gave some evidence that less quantity of sleep is related

to consumption of more energetic foods [7]. Fleig & Randler [8] reported a significant positive relationship between later bed time with fast foods and intake of caffeinated beverages; they also reported a negative relationship between later bed time and dairy intake. A research on Japanese female students showed the relationship between later sleep times with lower intake of protein and carbohydrate and higher intake of fat [9].

Healthy behaviors such as healthy diet choices have positive association with sleep quality [10-12]. Eating behavior is an important factor influencing weight [13] and refers to the selection of foods, both qualitative and quantitative aspects of it [14]. Inadequate quantity and quality of sleep may influence eating behavior [15], food choices and body weight. In a study in which eating behaviors were measured in healthy American women using the Dutch Eating Behavior Questionnaire, higher scores of emotional and external eating behaviors in those with poor sleep quality were observed [16]. Few studies were conducted on the relationship of eating habits and sleep quality in

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Asia; almost all of them have examined the association between sleep duration and obesity. Only one study that was performed on young Japanese women showed that those with a later midpoint of sleep preferred to begin meals later, eat for a longer time, skip meals more frequently, and watch TV at meals [9].

A study on medical students in both sexes, reported the prevalence of poor sleep quality to be 39.8%, despite no difference in sleep quality between the two sexes at BMI ≥25, male students had poor sleep quality compared to female students at BMI<25 [17]. According to another study, 40.6% of students had poor sleep quality and there was no significant relationship between sleep quality and BMI [18]. Both of these studies did not assess food intake or eating behavior and their relationship with sleep quality.

There are little literatures on the relationship between eating behaviors and sleep quality, also no research have been performed in this regard on healthy males, so the aim of the present study was to determine a relationship between sleep quality and eating behavior, food intake and some lifestyle factors such as physical activity on healthy male students.

MATERIALS AND METHODSThis study was conducted on male university students

residing at dormitories of Ahvaz Jundishapur University of Medical Sciences; they were assured of the confidentiality of their information, after which they completed a consent form. Inclusion criteria were as follows: an age range between 18 to 30, absence of chronic diseases and having no history of stressful life events (such as the death of a family member or a loved one, divorce, and so on) within the last three months. Using drug and medications such as antidepressants were considered as exclusion criteria. Accordingly, 17 subjects were excluded from the 200 students who had participated in the study, so data were obtained from the 183 remaining subjects. All subjects completed a general questionnaire on age, discipline and degrees in education, ethnicity, marital status and medical history in case of any disease condition. Sleep quality was determined using Pittsburgh Sleep Quality Index (PSQI) questionnaire. This questionnaire is an effective instrument used to measure the quality and patterns of sleep in these areas: sleep duration, sleep latency, habitual sleep efficiency, use of sleep medication, day time dysfunction and sleep disturbances over the last month. A total sum of five or greater indicates a “poor” sleeper. The Dutch eating behavior questionnaire was used to determine the score of three scales of eating behaviors: emotional eating (which included two subscales: emotional eating diffuse emotions and emotional eating clearly labeled emotions), restrained eating and external eating. International physical activity questionnaire was used to evaluate the level of physical activity; metabolic equivalent (MET) was determined and accordingly subjects were divided into three classes: inactive, medium activity and high activity. Food brief instrument according to food pyramid was used to determine food intake in each food group during the last three months. This questionnaire included these food items: bread, rice and pasta (bread and grain group), kinds of meat, legumes and egg (the meat and its alternatives group), milk, yogurt, doogh (traditional Iranian beverage, made by yogurt and mints), ice cream and cheese (milk and dairy products group),

fruits, vegetables and oils groups. Weight and height were measured with an accuracy of 0.1 kg and 0.1 cm respectively. BMI was calculated using the following formula: weight (in kilogram) divided by height squared (in meter).

All data were analyzed using SPSS version 17.0. Independent samples t-test was used to compare the mean score of different eating behaviors, food intakes and anthropometric measurements in two groups of students: those who had poor sleep quality (poor sleeper) and those with appropriate sleep quality (good sleeper). Chi- squared test was used to determine difference of categorical variables between these two groups of students.

Methods of the study have been summarized in a flowchart (Figure 1).

RESULTSThe result showed that 89 subjects (48.6%) had poor sleep

quality (poor sleepers) and 94 subjects (51.4%) had appropriate sleep quality (good sleepers). The mean age and anthropometric measurements (such as weight, height and BMI) had no difference

Figure 1 Summary of the study design.

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between the two groups of sleepers: poor and good (Table 1), but a significant relationship was observed between the score of sleep and age (Figure 2). There was no significant difference between two groups of sleepers on ethnicity, level of education and level of physical activity (Table 1). Emotional, restrained and external eating behaviors did not show any significant differences in the two groups of sleepers but emotional eating clearly labeled emotions score in the poor sleepers was more than the good sleepers, a trend close to significance (P= 0.065, Table 2). Pearson correlation test showed significant positive relationship between the score of sleep and the score of external eating, emotional eating, and the subscale of emotional eating (emotional eating clearly labeled emotions) (Figure 3).

Food intake was studied in two groups of students; poor and good sleepers. The poor sleeper students had less intake of doogh and total of dairy products. Milk intake was less in poor sleepers a trend close to significance. Poor sleepers consumed less fruits compared to good sleepers (Table 3). Pearson correlation test revealed negative relationships between the score of sleep and the intake of milk, doogh, total of dairy products and fruits (Figure 4).

DISCUSSIONThis study was conducted on male students; the results show

that poor sleepers had less consumption of some food groups. This study did not find any relationship between anthropometric measurements and sleep quality, although some studies have reported poor sleep quality in obese people [4,5]. The results of this study may be interpreted by the fact that most of the students had normal weight; however in a study performed on university medical students, there was no significant relationship between sleep quality and BMI [18].

According to the result of the study, poor sleepers had fewer intakes of doogh, total dairy products and fruits. Dietary pattern could affect many aspects of life, sleep as an important part of life may be influenced by the quality and quantity of diet. Some studies have confirmed the effect of diet on sleep. In a study that was performed on healthy elderly subjects, there was a significant improvement in sleep efficiency after consumption of fermented milk [19]. Also, in another study on elderly subjects, melatonin-rich night time milk caused better sleep [20]. Although in this study, poor sleepers consumed less milk but statistical analysis reported this difference as a trend close to significance;

Table 1: The frequency between different ethnicities, level of education and level of activity of poor and good sleepers.

P-value# Good sleepersNumber (Percent)

Poor sleepersNumber (Percent)

0.578

18 (52.9) 16 (47.1) Lor

Ethnicity

19 (61.3) 12 (38.7) Bakhtiyari8 (57.1) 6 (42.9) Turk9 (47.4) 10 (52.6) Kurd23 (42.6) 31 (57.4) Persian10 (47.6) 11 (52.4) Arab7 (70) 3 (30) others

0.92959 (51.8) 55 (48.2) Bachelor of science

Level of education 4 (57.1) 3 (42.9) Master of science31 (50) 31 (50) Medical doctoral

0.65942 (55.3) 34 (44.7) inactive

Level of activity34 (47.9) 37 (52.1) Medium activity18 (50) 18 (50) High activity

# Chi Squared test

Figure 2 Significant positive relationship between age and sleep score (r= 0.206, P= 0.005, P-value constant <0.001).

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Table 2: The mean ± standard deviation (SD) of age, anthropometric measurements and the score of different eating behaviors in poor and good sleeper students.

P- value#Good sleepers Poor sleepersMean ± SD Mean±SD

0.142 21.7 ± 1.9 22.1 ± 1.95 Age (years)

0.793 70.3 ± 13 69.8 ± 12.2 Weight (kilogram)

0.745 1.74 ± 0.08 1.75 ± 0.07 Height (meter)

0.761 22.9 ± 3.2 22.7 ± 3.6 BMI (kilogram /meter2)

0.945 2.36 ± 0.59 2.38 ± 0.62 emotional eating diffuse emotions (score)

0.065 2.29 ± 0.47 2.43 ± 0.51 emotional eating clearly labeled emotions (score)

0.127 2.31 ± 0.42 2.41 ± 0.43 emotional eating (score)

0.123 2.45 ± 0.44 2.56 ± 0.53 restrained eating (score)

0.224 2.52 ± 0.42 2.61 ± 0.51 external eating (score)# Independent Samples t-test

Figure 3 Significant positive relationship between the score of different eating behaviors and the score of sleep. a) Significant positive relationship between the score of emotional eating clearly labeled emotions and the score of sleep (r= 0.225, P= 0.002, P-value constant <0.001); b) Significant positive relationship between the score of emotional eating and the score of sleep (r= 0.179, P= 0.015, P-value constant <0.001); c) Significant positive relationship between the score of restrained eating and the score of sleep (r= 0.254, P= 0.001, P-value constant <0.001); d) Significant positive relationship between the score of external eating and the score of sleep (r= 0.217, P= 0.003, P-value constant <0.001).

accordingly, the results confirmed the less intake of doogh-that is made by yogurt- in poor sleepers compared with good sleepers. Doogh is a fermented dairy product and it seems that the results are the same as that of Yamamura et al [19] where Lactobacillus helveticus fermented milk was used. Also poor sleepers had fewer intakes of fruits; the negative relationship between fruit intake and sleep quality revealed that more poor sleep quality was related to less intake of fruits. Stamatakis

and Brownson [21] showed that less than seven hours of sleep a day in adults was associated with fewer intakes of fruits and vegetables and more intakes of energetic foods without useful nutrients. Some studies have shown that intake of some kind of fruits like kiwi and cherry could improve sleep [22, 23]. Since milk and dairy products are rich sources of the amino acid Tryptophan (Trp) and fruits are good sources of carbohydrates [24], the possible mechanism that could interpret the role of

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Figure 4 Significant negative relationship between daily serving intakes of different foods and the score of sleep. a) Significant negative relationship between daily serving intakes of milk and the score of sleep (r = -0.153, P= 0.039, P-value constant <0.001); b) Significant negative relationship between daily serving intakes of doogh and the score of sleep (r= -0.181, P= 0.014, P-value constant <0.001); c) Significant negative relationship between daily serving intakes of total dairy products and the score of sleep (r= -0. 202, P= 0.006, P-value constant <0.001); d) Significant negative relationship between daily serving intakes of fruits and the score of sleep (r= -0. 207, P= 0.005, P-value constant <0.001).

Table 3: The mean ± standard deviation (SD) of food intakes from different food groups in poor and good sleeper students.

P- value#Good sleeper Poor sleeperMean ± SD Mean ± SD

0.443 3.3 ± 2.4 3 ± 2.2 bread

0.088 4.7 ± 2.4 5.4 ± 2.6 rice

0.296 1.1 ± 3.1 0.7 ± 0.8 pasta

0.764 9.7 ± 5.1 9.9 ± 4.1 total of grain group

0.062 0.6 ± 0.8 0.4 ± 0.6 milk

0.211 0.8 ± 0.6 0.7 ± 0.6 yogurt

0.034* 0.7 ± 0.6 0.5 ± 0.4 doogh

0.553 0.7 ± 0.8 0.6 ± 0.7 ice cream

0.582 0.6 ± 0.6 0.6 ± 0.7 cheese

0.049* 3.4 ± 2.2 2.8 ± 2 total of dairy

0.781 2.6 ± 1.6 2.7 ± 1.9 meat

0.88 0.7 ± 0.6 0.7 ± 0.5 legume

0.46 0.9 ± 0.8 0.8 ± 0.8 egg

0.933 4.2 ± 2.1 4.2 ± 2.6 total of meats and its alternatives

0.002* 1.4 ± 1.1 0.9 ± 0.7 fruits

0.061 0.6 ± 0.8 0.4 ± 0.5 vegetables# Independent Samples t-test; *Significant level < 0.05

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dietary components on sleep is their assistance in synthesis of serotonin and melatonin, two sleep-promoting neurochemicals [25]. In the brain, Trp could be metabolized into serotonin and melatonin; moreover, some nutrients like carbohydrates can assist tryptophan in crossing the blood brain barrier so this can increase the brain’s tryptophan levels thereby increasing the levels of serotonin and melatonin [7].

The findings of this study showed no significant difference of eating behaviors between the two groups of poor and good sleepers; only emotional eating was in a trend close to significance; however the result confirmed a positive relationship between the score of different eating behaviors and the score of sleep. It means that with increasing score of each eating behavior, the score of poor sleep quality (according to Pittsburgh sleep quality index) was enhanced. In a study conducted in people at risk of Type 2 diabetes and obesity, eating behavior was determined using three factors eating questionnaire. The results of this study showed association of lower sleep quality with increased hunger rating and uncontrolled emotional eating [15]. In another study on healthy women in United States, the scores of emotional and external eating were significantly higher in poor sleepers and they also found a negative relationship between short sleep duration and intake of foods in subjects with a greater tendency toward emotional eating behavior [16]. Emotional eating could be explained as a response to some conditions like depression, anxiety or fear [26]. It seems that people with high tendency to emotional eating, suffer from poor sleep quality; because of the association between sleep and emotional stress like anger, anxiety, dysphoria, worry and so on [27].

Age and university exams can be accounted as confounder variables; however age had no statistical difference between poor and good sleepers. The limitation of the study was working on university students who were resident in dormitories. To minimize this effect, this study was conducted in October, and their sleep habits and dietary intakes were studied during the past one and three months, respectively. This duration included summer holidays, when students were staying in their homes. Moreover this study did not use any objective measurement of sleep like actigraphy. The strength of the study was using the Pittsburgh sleep quality index and Dutch eating behavior questionnaires to determine the sleep quality and eating behavior, respectively. More documents have shown that these questionnaires are more valid and reliable compared to other questionnaires [26, 28-31]. Finally, it is suggested that further studies should be performed on some common emotional stresses and their relationship with sleep quality and eating behaviors.

CONCLUSIONThe results of this study indicated that intake of some food

groups such as dairy products and fruits were associated with the quality of sleep, moreover a normal eating behavior had a positive relationship with the quality of sleep.

ACKNOWLEDGMENTSThe authors would like to thank the education deputy of the

School of Paramedicine, Ahvaz Jundishapur University of medical Sciences, for supporting this study as a project course. The

authors deeply appreciate the students who participated in the study and Dr. Ario Zare for his useful comments.

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Lotfi M, Al-Hosseini MK, Jafarirad S (2015) The Relationship of Sleep Quality with Eating Behavior and Food Intake among Male University Students. J Sleep Med Disord 2(5): 1034.

Cite this article

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